Across Colorado and the West there is a growing awareness of the high cost and in many cases the lack of availability, of water for landscaping and development. Since 2001, our team has been exploring alternatives to thirsty turf grass and exotic landscape plants by focusing on native plant species that require little or no water. Our nonprofit environmental center is celebrating the 20th anniversary of our founding, spurred by the concept of a homebuilder, McStain Neighborhoods, and McWhinney, the master developer of Centerra, an award-winning 3,000-acre master-planned community in Loveland, which readily adopted the visionary idea for preserving and managing open space within the development.
Over the past two decades, our center has worked with McWhinney and other landowners, within Centerra and beyond, to establish or restore hundreds of acres of native vegetation. The cost of maintaining native grass can be 90% less than turf grass due to the avoided costs of mowing, watering, fertilizing, and other maintenance. However, managing these areas requires specialized skills and knowledge to be successful. As the executive director of HPEC, I’ve recently published a book, SUBURBITAT, that highlights the center’s work and tells the story of Colorado’s history from its primordial past to the present-day development of the land.
The book provides detailed information on how to establish and maintain beautiful, sustainable landscapes that conserve natural resources and provide a distinct sense of place, celebrating Colorado’s unique natural diversity. The book provides detailed instructions for others who wish to create water-saving native landscapes, as well as explore the social aspects of landscaping in collaboration with nature. This includes managing expectations and establishing realistic timelines for the establishment of native open spaces and living with rather than eradicating the wildlife that is attracted to them.
The development community has the opportunity to create landscapes that are vibrant and interesting year-round, in a way that will allow people and wildlife to continue to thrive. We have observed firsthand how dramatically and rapidly our local birds and pollinators recover when we grow native plants in our gardens. There are over 40 million acres of turf grass in the U.S. More herbicides, pesticides, and fertilizers are used on this crop, per acre, than any other crop. Some 800 million gallons of gas are used every year to mow American lawns. Here in Colorado, a minimum of 18 gallons of water are needed per square foot, per year, to keep lawns green. The average use of water in Colorado for landscaping alone is about 90 gallons per person per day.
Over the next 20 years, Colorado’s population is expected to grow by roughly 30%, increasing from 5.7 million in 2019 to 7.52 million in 2040. As populations grow, particularly along the Front Range, pressures on our dwindling water resources will continue to increase. Rising temperatures cause plants to accelerate transpiration, which increases the amount of water used to maintain landscaping, putting additional strain on water supplies. There is simply no question that our water usage in landscaping is unsustainable. LEED construction, which reduces energy consumption in commercial buildings, is a great example of the way that businesses cannot only anticipate and respond to environmental issues but also can lead the process toward sustainable development in ways that are in turn rewarded in the marketplace. Sustainability is no longer an isolated movement but rather an imperative and an expectation for many environmentally conscious homebuyers. Sustainable landscaping is a natural extension of this concept.
Access to trails, nature, and open space are also frequently rated as highly desirable amenities for potential homebuyers. Far from being an inferior concession to economy and practicality, native landscapes can be beautiful and provide year-round interest while supporting wildlife in the midst of the communities that we design and build – restoring nature where we live, work, and play.
Jim Tolstrup is the executive director of the High Plains Environmental Center, located in the Centerra master-planned community in Loveland. The environmental nonprofit is focused on open space management, wetland restoration, native plant propagation, and environmental education and outreach. He can be reached at jim@suburbitat.org
(Originally published in the Elephant Journal – 2009) I felt a bit depressed and aimless before Christmas last year. I know I’m not unique in this. Many people say that helping others makes one a happier person and I’ve experienced this myself. So when the opportunity came to drive a truck full of donated toys, food, and clothing to the community of Wounded Knee on the Pine Ridge Indian Reservation in South Dakota, I jumped at the opportunity.
The name Wounded Knee is infamous in American history because of one very dark day, December 29, 1890. On this day 350 men, women, and children, members of Chief Big Foot’s band of Minneconjou Lakota (Sioux,) were mowed down by the guns of the U.S. Seventh Cavalry and buried in a mass grave. Big Foot’s people were practicing the Ghost Dance, a non-violent prayer for the restoration of the environment, the return of the buffalo, and the return of their many dead Lakota relatives. The Ghost Dancer’s dream of protecting the culture and ecology that existed on the Great Plains for over ten thousand years died there in the bloody snow at Wounded Knee and the legal right to practice their traditional religion would not be returned to the Native Americans until a special act of the U.S. Congress in 1978.
In 1986 a group of Lakota including Chief Arvol Looking Horse, a descendant of Chief Big Foot, initiated an annual commemorative ride on horseback that retraces the journey to Wounded Knee by Big Foot’s people. The Ghost Ride, as it is called, was intended to “wipe the tears” of the Lakota people and release the psychic trauma of a troubled place.
In typical Lakota style, these warriors endured great hardship on their cold journey and laughed the whole time. Once when the riders had not eaten for a long time they came to a small town with a Chinese restaurant that had an “all you can eat” buffet; after watching some of these big guys were chowing down a very anxious owner came out of the kitchen and shouted, “You go now!” The telling and re-telling of this story provided them with hours of entertainment on the long ride.
Chief Looking Horse has worked to protect sites sacred to indigenous people in North America and around the world and received the Temple of Understanding award at the United Nations on October 18, 2006, for his work in promoting world peace.
Today Wounded Knee is a small community of about 300 people in Shannon County, S. D. the second poorest county in the United States. Toward the end of his second term, President Clinton visited Pine Ridge Reservation and pledged to do something about the poverty there but like so many other promises made to the Indians, so far nothing has happened.
Our travel weather on December 23rd was sunny and strangely mild but the snow from a recent blizzard was piled deeply along the roadside. My companions traveling in a separate vehicle were Beverly, a Buddhist, who has organized these donations for Wounded Knee for many years, and Christinia a Lakota woman whose sister-in-law was recently killed in a car accident in the reservation, leaving behind 5 children. My co-pilot in the truck was David, a member of the Unity Church, three times divorced, and like myself looking for a little bit of meaning in the holiday season.
When we got to Pine Ridge we stopped at Big Bat’s store and gas station, a local landmark whose name derives from Baptiste “Bat” Pourier, a French trader of the 1800s who married a Lakota woman. At Big Bat’s two local Indian women, Loretta and Misty offered us beaded earrings which they make to sell for a little holiday cash for their families. I bought two pairs for our young friends Lauren and Mikayla with whom we spent Christmas day back in Colorado. A couple of local drunks panhandled us and harangued us about Jesus.
We arrived at Wounded Knee around 10 p.m. The night breezes remained warm. I have been to this place a half dozen times since the mid-seventies and it always feels like a place where there is some kind of gap, where seen and unseen worlds, past and future overlap in a way that can be unsettling.
Stopping at a little church, we unloaded our U-Haul truck which was filled floor to ceiling with frozen turkeys, potatoes, carrots, apples, oranges, and canned goods, as well as 4 or 5 bikes, presents marked for recipients by age, and lots of new clothes with the labels still on them. I felt heroic and happy like one of the characters in the Christmas specials I watched when I was a kid or maybe the Grinch when his heart grew three sizes.
In the midst of this reverie on the meaning of Christmas, I saw one gift in the pile which really hit me. The gift was a puzzle for a toddler that had elephants, tigers, and monkeys on it. These questions struck me, “How many children that age will ever see those animals?” and “Will those animals continue to be part of our world in the near future?”
The Lakota have a prayer “mitakuye oyasin” which means “all my relations.” To this day at the core of their culture is an ingrained sense of not taking more than one needs and always leaving enough for other beings, “our relations.” This is one lesson that our indigenous brothers and sisters dearly wish that we would learn also.
It struck me that the whole Christmas iconography is threatened. The little town of Bethlehem now lies in the midst of a region that has long been divided by violent conflict and due to global climate change, reindeer, and polar bears; even the North Pole itself is in jeopardy. Whether we think that Santa Claus is silly or charming the question looms large, what will we tell our children and ourselves when the very heart of our Christmas dreams, the North Pole, ceases to exist? It may seem like a foolish question, but after all, who has actually been to the North Pole? The plight of polar bears drowning because they can’t swim the increasing distance between the shrinking polar ice and the mainland may seem remote, maybe even inconsequential. But what is truly at risk here is the essence of our humanity and possibly our continued existence as well.
The stories we live by during this season are important, whether it is Santa Claus bringing toys to all the children of the world, the blessing through the long dark nights, or three wise men guided by a star, seeking a holy child born into humble circumstances. These stories point to the best potential of the human spirit. Christmas is one time that we seem to recognize that giving to others brings us great joy.
Perhaps we could transfer this important lesson, learned in the Christmas season, toward giving a little bit back to the Earth which is our only home, as well as the home of every known living creature. Leading scientists say that we may have ten years at best to fix the problem of Co2 emissions and climate change; beyond that, the damage may be irrevocable. But solutions to this looming ecological crisis exist, awaiting implementation.
The real test of the human spirit will be whether we can learn, like Ebenezer Scrooge, to care about others, keeping Christmas in our hearts throughout the year and possibly conserving a little bit for the future. Or will our own children of the next generation (over nine billion of them) wander like poor Tiny Tim, hungry, sick, and neglected, due to our present thoughtlessness? Will our own fate be like that of the ghost dancers, fervently wishing for the return of all that was beautiful and dear to us after it is gone, never to be seen again?
Driving back from Wounded Knee on Christmas Eve I made a silent prayer for the thousands of little birds who had been pushed by the snow to the highways cleared edge, and for the rest of us as well, “May all travelers on this uncertain road arrive home in peace and safety, All My Relations.”
When developers build rooftops, parking lots, and other impermeable surfaces, rain, and snowmelt can no longer percolate into the ground. The resulting stormwater runoff must be managed to prevent flooding. It once was common practice to collect stormwater in concrete pits and dump it into nearby rivers and streams by piping it underground. In some cities, entire rivers have been channelized and sometimes buried. Many of these rivers have been restored in recent years after people realized the ecological harm that this practice caused, as well as the recreational, aesthetic, and educational benefits that may have been previously overlooked.
Over the last few decades, the standard for stormwater engineering has moved toward creating water-quality ponds that slow down the turbulence of the water and allow sediment to drop out. Ponds and conveyances that include vegetation can also remove nutrients the stormwater may have picked up in its flow. These nutrients come from natural deposition, landscape fertilizer, pet waste, soap used for washing cars, etc. Nutrients that reach ponds and lakes encourage the growth of algae, which can reduce oxygen levels in the water, killing fish and other aquatic life.
Here at the High Plains Environmental Center, within the Lakes at Centerra neighborhood, we have far less algae than typical lakes within a residential development. The unmown native vegetation (shrubs, grasses, and wetland plants) in the setbacks and stormwater conveyances around us function as a biological filter, helping to sequester nutrient run-off from adjacent developed sites. The proof of our strategy’s environmental success is measured and proven in periodic water quality testing.
Well-constructed, and well-managed, stormwater ponds can be aesthetically pleasing amenities that benefit wildlife while offering educational and recreational opportunities for residents and visitors
Stormwater ponds, though necessary, often are viewed by developers as a liability. They can be unsightly when not well-designed, fill up with trash carried along by storm flows, and take up space that would otherwise be buildable. Well-constructed, and well-managed, stormwater ponds, on the other hand, can be aesthetically pleasing amenities that benefit wildlife in the built environment while offering educational and recreational opportunities for residents and visitors. An artfully designed pond or natural area can allow residents access to nature while protecting wildlife from excessive disturbance. Although it can be hard to resist the temptation to put paths all around a pond, or throughout an open space, the benefits of limiting wildlife disturbance are well worth the effort. Providing a cover of vegetation around ponds can increase nesting habitat for songbirds and allow wildlife to retreat to a place of peace and safety when necessary.
Wetland
One of the most difficult things about vegetating stormwater ponds is predicting the amount of moisture the pond will ultimately hold. Wetland plants tend to grow in very specific hydrological zones, and choosing the appropriate species can be challenging. We have addressed these issues by using diverse seed mixes that include various grasses, sedges, and rushes. Using this “shotgun” approach helps to ensure that there will be sufficient plant diversity. In the beginning, when the pond is first excavated, it may be drier. Over time, as the area around the pond gets built and runoff increases, the pond will become wetter, and plants will distribute themselves in accordance with the changing hydrological regime. In general, cattails, while native, should be discouraged in wetlands and stormwater channels. Although cattails provide filtration and cover for wildlife, they are aggressive and can reduce habitat quality by creating a monoculture. Our goal should be to create a diverse wetland plant community.
When designing a pond, it is desirable to create an undulating shoreline and varying topography on the pond’s bottom. Shallow, flat-bottomed ponds should drain completely, or they can become a breeding ground for mosquitoes. Ponds that include plunge pools 5 feet deep or deeper can hold some water year-round and allow minnows to survive over winter. Holding back any amount of water in a stormwater pond may require water rights to offset the evaporative loss. People may be concerned about mosquitoes in deeper water, but mosquitoes can breed in an inch of water in concrete drains. Natural predators like minnows, tadpoles, and dragonfly larvae also will be present in the deeper areas of these ponds and can help control mosquito larvae.
Many people don’t realize how degraded the environment was in the United States in 1970, without the environmental protections that exist today.
In the summer of 1969, the Cuyahoga River burned because of the petroleum distillates that were being dumped into it. Three million gallons of oil spilled in Santa Barbara, killing sea life and ruining the beaches. Dioxin and other poisons were dumped directly into lakes and rivers. Whales were being hunted to the brink of extinction and the bald eagle, the symbol of our nation, was reduced to the brink of extinction.
Within the next two years, under President Nixon, the Endangered Species Act and Clean Air Act were passed through bilateral collaboration in Congress, and the Clean Water Act was amended and strengthened.
As a result of these efforts, the aggregate emission of six industrial pollutants has decreased by more than 73 percent, bald eagles have recovered to the point where they are relatively common, and whale species such as the humpback have steadily increased.
I feel it is important to reflect on some of our triumphs even as we recommit ourselves to engaging in the critical work of saving the Earth for future generations, and we still have a long way to go.
This generation faces some of the greatest environmental challenges yet—climate change, melting ice caps, and mass extinction, as well as threats to our growing human population, drought, hunger, homelessness, war, and now the global pandemic. How do we sustain ourselves as we engage in this arduous task of restoring our world?
Let me ask you something: do you care about nature, about birds, animals, and all that is wild?
Are you frightened about your future, and the future of your children and grandchildren?
Are you frustrated about seeing legal protections for human health and environmental integrity eroded, undermined, and repealed?
Are you angry about the inertia of our leaders in the face of devastating climate change and of threats to life on Earth?
How do we then sustain our sanity and equilibrium in the face of such daunting threats?
How do we live a decent life in midst of such grief and terror?
Species Extinction and Human Population Growth
How do we connect with our own hearts and remain available to our world and engage in winning hearts and minds to the cause of global environmental stewardship?
The fact is that we have all that we need to tackle these challenges—scientific knowledge, technology, and money—and we have nature’s tremendous power for regeneration, healing, and growth.
What we are lacking as a society is the will to undertake this work, the understanding of why this is so critically important, the ability to communicate our vision, and the tolerance to work with individuals with widely divergent points of view and interests.
Gus Spaeth, Scientist, Environmental Lawyer, and United States advisor on Climate Change said,
“I used to think that top environmental problems were biodiversity loss, ecosystem collapse and climate change. I thought that thirty years of good science could address these problems. I was wrong. The top environmental problems are selfishness, greed and apathy, and to deal with these we need a cultural and spiritual transformation. And we scientists don’t know how to do that.”
The practice of mindfulness meditation—following our breath and connecting with our own basic state of being can provide us with a space in which we can restore and recharge. In many ways, I think this provides the missing element.
Those of us who cared about the earth in the 60s and 70s are now in our 60s and 70s. The torch is passed to the younger generation, but you are not alone. Right now, across the world, Earth Day is being celebrated in 193 countries.
And the whales, the eagles, the forests, and the oceans are continuing to do what they do because someone cared.
Earth Aspiration: May all beings everywhere be happy and free from suffering. May the words, thoughts, and actions of my own life contribute to that happiness, well-being, and freedom of all living things.
The growth of cities in the American West has increased water consumption from the Colorado River and pushed this critical natural resource beyond its limits. Yet we could reduce some of this demand within the communities that we design and build by switching to a style of landscaping that is more appropriate for our region, thereby conserving water while restoring some of our state’s unique biodiversity.
Snowmelt from the mountain peaks of Colorado provides water to over 40 million people in 14 western states.
Here in Colorado, where we typically get 12–15 inches of precipitation per year, the average person uses 150 gallons of water per day. Sixty percent of residential water usage goes to support landscaping. This amounts to approximately 90 gallons of water per person per day used to keep exotic landscapes on life support.
When we look at wild landscapes in the fall, the changing colors reveal patterns that may be imperceptible at other times of the year. These patterns in the landscape provide subtle clues to the ways that plants are arranged in nature, based on available soil moisture.
The arrangement of plants in nature gives us subtle clues about the moisture content and soil type of a site. When we know where plants want to be, we can design landscapes that require little or no water because they are in the correct place to support them.
In planning restoration projects, ecologists look at the aspect (the direction the site faces and the amount of sunlight it receives) as well as the degree of slopes, variations in soil moisture, and other conditions of the site. This same information is also valuable when planning sustainable landscaping projects utilizing native plants with minimal watering or maintenance costs. The grounds that surround buildings receive different amounts of stormwater, sunlight, exposure to wind, and other influences than undeveloped open spaces. To create a low-water use garden, it is necessary to evaluate the site in these terms and put the right plant in the right place for our purposes.
In 2007–2008, McWhinney (the developer of Centerra, a master-planned community in Loveland, Colorado), High Plains Environmental Center (HPEC), Ark Ecological Services, and BHA Landscape Design created a document called the Centerra Stormwater Pond and Natural Areas Design Guidelines. The guidelines won a Land Stewardship Award from the American Society of Landscape Architects in 2009. Although this document is primarily about the design and construction of native open space, it has influenced our thinking on all aspects of landscape design.
How do you grow a wetland plant like blue vervain (Verbena hastata) in a garden that is never watered? It’s very easy. Just plant it where the downspout deposits rainwater. This simple form of rain gardening can be applied on a microscale or to a large-scale landscape.
In front of our visitor center at HPEC is a bioswale. It is a low channel that receives the stormwater runoff from our parking lot. The channel has a series of pools that are excavated to different depths. Each shallow pool contains plants with varying degrees of moisture requirements. The channel banks have plants that require increasingly less moisture up to the top of the bank, which receives virtually no moisture except our natural precipitation. This type of swale can also improve water quality by removing nutrients from fertilizer, pet waste, and other sources that may have been picked up in the water along the way.
The bioswale at HPEC utilizes stormwater runoff in an otherwise unirrigated landscape.
The concept of passive rainwater harvesting has been implemented to a large extent in other regions of the country. In Colorado, our complicated water laws do not allow for the evaporative loss of rainwater trapped in ponds of any size unless the landowner has water rights to offset it. However, it is possible to create high and low spots that allow rainwater to flow through the landscape slow enough to provide irrigation to the plants before flowing on.
When we work with nature in this way, placing plants in the appropriate zone in the landscape, and literally “go with the flow”, we can create beautiful, sustainable landscapes, reduce costs, conserve resources, and preserve the natural beauty of Colorado.
At HPEC, our native plant gardens are ablaze with color from spring until frost with virtually no watering.
Picture a lean, mature gentleman with a floppy sun hat furiously waving a large white net over the tops of shrubs and perennials on a warm summer day. This is Dr. Paul Opler, our neighbor and a frequent visitor to our gardens at the High Plains Environmental Center (HPEC) in Loveland, Colorado.
Paul is an entomologist of some renown. His list of published work, academic lectures, and public education workshops are both extensive and impressive. He is a professor of Bio agricultural Sciences and Pest Management at the Dept of Agricultural Biology at Colorado State University. His specialty is Lepidoptera (moths and butterflies), but these days he is in pursuit of bees.
Paul says our gardens at HPEC are a sort of “ecological supersite” because of the density and diversity of native plants growing here. His ongoing study has included 111 plant species of woody plants and forbs (herbaceous flowers). Aside from HPEC, the study includes locations in northeastern Colorado and adjacent Wyoming, seeking clues to plant/insect associations and other information that may be helpful in managing a garden, or natural area, as a pollinator habitat.
For years we’ve heard people say that native plants provide habitat for the pollinators and other wildlife with whom they coevolved. I’ve said this myself in numerous talks and on garden tours. I can tell you by casual observation that I see a diversity of pollinators in our gardens and that they appeared quickly after volunteers helped to plant extensive gardens of native plants on our 4-acre site. However, we have never had solid data about which pollinator species were attracted to our gardens and which specific plant species were attracting specific species of insects.
The data from Paul’s study is still being evaluated. Bee specimens collected at HPEC and elsewhere are being identified by a team of experts, primarily at CU Boulder. Paul estimates the total number of species collected at HPEC to be more than 100 species. Many of the bees are very difficult to identify to species, although most can be identified by genus fairly easily (for an entomologist or well-informed amateur).
Beyond identifying the genus, arriving at the exact species can be extremely difficult. Paul notes that male and female bees of the same species often look quite different, and the differences in species can be so tiny that they often can only be observed in a microscope. The differences in sex within each species can be almost to the degree that instead of having to determine which of the 946 species native to our state we might be looking at, it’s necessary to identify which of the 1892 combinations, including species and sex, they might be.
Colorado is home to nearly one-quarter of the approximately 3,500 bee species found in the United States and Mexico. Some bee species, such as the genus Bombus or bumble bees, nest in the ground. For this reason, keeping some areas of bare ground is a helpful practice when maintaining landscape for pollinator habitat. All of the bumblebees we see in Colorado, a total of 28 species, are native bees. Only 5 species of this group were found at HPEC, including the brown-belted bumblebee (Bombus griseocollis), Hunt’s bumblebee (Bombus huntii), a few Southern Plains bumblebees (Bombus fraternus), and one red-belted bumblebee (Bombus rufocinctus). The last and most exciting species found at HPEC, the American Bumble Bee (Bombus pensylvanicus), was a frequent visitor to the gardens. This species has declined over much of its range and is being considered for listing as endangered. The Nevada Bumblebee (Bombus nevadensis) was not found, although it is relatively common in Larimer County.
European honeybees (Apis mellifera) are commonly found in gardens. The decline of honeybees is a global concern, not least of all, because human beings are dependent on the crops they pollinate. However, honeybees are not particularly helpful for the diversity of native bees. Honeybees can compete with native bees for forage, as well as being a vector for diseases and parasites that affect native populations.
Solitary bees, such as mason bees (Osmia sp.) and leafcutter bees (Megachile sp.), are most active in spring. These are the bees that utilize manmade “bee hotels” constructed from sections of bamboo or drilled blocks of wood. Placing bee hotels near plants of the Rosaceae family is particularly beneficial for leafcutters that prefer these plants for sealing up their egg chambers.
Maximilian sunflower (Helianthus maximiliani) Bombus cinereothorax
Lisa Mason, Horticulture Agent at Colorado State University Extension, Arapahoe County, suggests keeping the following in mind with bee hotels and nesting boxes:
Different species need different diameters of tunnels. Megachile bees need tunnels that are approximately 5-6mm, while Osmia can vary between 6mm-9mm.
· All tunnels should be a minimum of 5 – 6 inches long, and the tunnels need to have a back (only one entrance in).
· The nest box should have a frame or roof that slopes to protect the nest box from rain.
· Typically, the nest box should be anywhere from 3-6 feet off the ground and mounted firmly.
· The nest box needs sunlight throughout the day. The bee nest box should generally face south to southeast to maximize sunlight.
· Maintenance is a big consideration in bee nest boxes/bee hotels. Over time, nest boxes can build up mold, fungi, pollen mites, and other pests/pathogens. Depending on what the nest box is made of, the next box should be replaced every year or two or designed in a way that tubes can be replaced every year. Wood blocks should be cleaned with a bleach solution.
· Since nest boxes need to be cleaned and replaced, it’s hard to know exactly when to clean or replace them since different species of bees emerge at different times. For this reason, having two nest boxes is recommended. Place one in the garden all season, and leave throughout the winter. When spring arrives, add the new nest box. As soon as all the solitary bees and wasps exit the previous nest box, remove it, and leave the new box until the following spring. Repeat with a new or cleaned box each year.
Throughout the world, plants have developed chemical means of repelling insects that may eat the plant, its fruit, or its seeds. Often, specific insects have coevolved with the plants, developing a tolerance for these specific chemicals. While this tolerance may allow some of these insects to damage the plant, it may also allow them to become better pollinators for that plant. The vast number of these intricate plant/pollinator relationships is not fully known.
These plant-insect relationships are one reason introduced plants from Europe and Asia can become invasive in the North American prairie, displacing native plants and disrupting ecosystem function. Once in their new range, invasive plant species typically do not have the natural insect predators that helped keep them in check in their native range. Operating outside of these native plant/insect agreements, negotiated within the subtle balance of coevolving species, invasive species expand rampantly, often outcompeting natives. The destruction of wild plants and competition with weeds reduces forage for native insects.
Evolving together can also lead to specialized adaptations that benefit both pollinators and plants. An example of a mutually beneficial symbiotic relationship between native plants and insects can be found in the relationship between the soapweed yucca plant (Yucca glauca) and the yucca moth (Tegeticula yuccasella.) The yucca plant is pollinated primarily by the yucca moth and depends on this moth to reproduce. The moth, in turn, lays its eggs in the developing flower before it develops into fruit. The female moth leaves a pheromone scent that lets other yucca moths know that eggs have already been laid on this plant. When the larvae hatch, they eat some (but not all) of the yucca seeds as they’re developing, and both species survive for another generation in the process.
There are many ways in which plants have adapted to target specific pollinators, but a common strategy is developing specific flower forms to limit which insects can access their pollen. Insects that are successful in accessing the pollen and nectar of a particular species of flower are likely to go to other flowers of the same type. This helps to ensure fertilization and eliminates some of the waste of pollen being carried to different plant species.
Anise hyssop (Agastache foeniculum) and Southern Plains bumblebee (Bombus fraternus)
Some plants can be pollinated by many different species of insects. These plants include many members of the Asteraceae family, with open flowers that are easy to access. Pollinators that visit many types of flowers are referred to as “generalists” or polylectic. Insects that limit associations to one genus or species of plants are called oligolectic.
Tube-shaped flowers, such as penstemons, are particularly attractive to bumble bees. The buzzing vibrations of bumble bees cause a release of pollen in these flower species, the timing of which rewards both the insect and the flower. Bees, butterflies, and other insects have different tongue lengths, which also limit access to the flower to specific insects.
Bees that visit the same gardens repeatedly are described as “trap-lining.” This refers to insects or other organisms visiting a string of sites periodically in search of forage. Hummingbirds travel to sites daily in the summertime where they have previously found nectar; they do some quick collecting and then move on. These individual organisms learn a route and check it repeatedly. This is a great example of why urban and suburban gardens that are rich in native plants are important to pollinator populations. These species will learn your garden’s location. Once they have found forage, they will return repeatedly.
So, who won the insects’ plant popularity contest in our gardens? By far, the most visited plant, by the widest range of species of insects, was Bigelow’s tansy aster (Machaeranthera bigelovii). Second to that were sunflowers, (Helianthus nuttallii, H. maximiliani, H. pumila, H. annuus). Rocky Mountain beeplant (Cleome serrulata [syn. Peritoma serrulata]), and fernbush (Chamaebatiaria millefolium), were also popular with a wide variety of insects.
Among the most popular plants were many that have extrafloral nectaries. Many plants produce nectar in their flowers to attract pollinators, but some flowers have “extrafloral nectaries.” These are glands that produce nectar elsewhere on the plant. The additional sources of nectar on these plants not only increase pollinator traffic but, in some cases, also attract ants. The ants, in turn, defend the plants from predation by other insects.
Here are some recommendations for gardeners that Paul observed or confirmed at HPEC.
1. Bees are attracted to intense concentrations of flowers; the larger the area, the better.
2. Bees require a succession of plants over the year, but some specialize in particular plant families so it’s good to have a succession of bloom within those families, including Asteraceae, Rosaceae, Lamiaceae, Fabaceae, etc.
3. Don’t clean up dead stalks or remove old plant material until spring, if possible. Pollinators may over-winter in plant stalks. Walking in the garden can also be destructive as insects may be just below the surface.
4. Encourage a bit of weediness. Plants that aggressively self-seed, such as sunflowers, Rocky Mountain bee plants, and fetid marigolds (a favorite at HPEC), can supply an abundance of flowers for insect forage. We also find that these plants help to fill the space and reduce competition from more problematic weeds.
5. Provide bee houses if possible.
6. Provide areas of bare ground for nesting.
6. Keep plantings in sunny areas; most bees forage mainly in the sunshine. Honeybees and bumble bees are exceptions.
7. Avoid pesticides as much as possible. Know where your plants are grown, and always avoid buying plants treated with systemic pesticides, particularly neonicotinoids!
Last year I wrote a book about restoring nature in the environments where we live, work, and play focusing on the use of native plants in landscaping and habitat restoration. At the end of the book, I included the following comment: The communities that we design and build need to have a positive effect on natural areas and resources, or nature will have a negative effect on us.
The previous summer hundreds of thousands of acres of forests were burning throughout the West. In cities along Colorado’s Front Range, fumes and smoke hung in the air so thickly at times that it created an otherworldly light. Air quality was in the poor to dangerous range off and on from August through much of October.
On Oct. 22, 2020, the East Troublesome Fire leapt over the Continental Divide, blazed through many favorite hiking spots in Rocky Mountain National Park, and reached the western edge of the town of Estes Park.
My comment was meant to be philosophical. Of course, there are feedback loops from nature, and a species that destroys its environment will begin to die out as its ecosystem declines. But humans are good at manipulating that feedback, or so we may believe. The thought that a raging fire could consume an entire neighborhood, destroying nearly 1,000 homes in a single afternoon, as it did in Superior, Colorado on Dec. 30, 2021, was beyond anything we had previously imagined. This single event shattered the notion of a “fire season” in Colorado and introduced us to the term and the lived experience of an “urban fire storm.”
The fire cycle is certainly not new to our region. Historically, lightning strikes caused low-level grass fires from the prairie to the montane zone, elevations of approximately 4,500 to 9,000 feet. The montane zone sometimes called the “ponderosa pine savanna,” is a landscape shaped by fire. Ponderosa pines naturally lose their lower branches, which otherwise could become ladder fuel that could help a fire reach the crown of the tree. The pumpkin orange bark of a mature ponderosa pine has evolved to slough off in layers when exposed to fire, making them somewhat flame resistant.
Before the arrival of white settlers, fire shaped the montane zone into a park-like environment with large trees spaced far apart in a grassland filled with shrubs and wildflowers. Fire helped to clear out and renew the understory periodically, and kept these trees from becoming too crowded. The wide spacing of trees helped to keep this old-growth forest healthy by limiting the number of trees, thereby reducing competition for available ground moisture.
Low-intensity fires can help to regenerate growth in Western landscapes.
Snowmelt from Colorado’s subalpine forests provides water to over 40 million people in seven Western states.
Indigenous people used fire to regenerate the land and improve habitat for the game on which they depended. The absence of these traditional land management practices, combined with the excessive suppression of naturally occurring fires within the last century, has resulted in an overgrown, and less resilient forest. It’s estimated that 80% of the trees in Colorado are less than 100 years old. People who say that “trees are the answer” and apply this standard universally, regardless of bioregion, may be missing an important point about how our ecosystem functions in the Rocky Mountain West.
When fires ignite in the overgrown forests that currently exist, they don’t just burn along the forest floor. They leap up into the crowns of trees, creating such an intensity of heat that they often burn the soil, which undermines the forest’s recovery. When storm events hit the scorched slopes following this type of fire it can cause erosion, siltation of streams and acidification of water which corrodes the pipes of municipal water supplies.
In both the montane and sup-alpine forest prolonged drought and milder winters have exacerbated the issues brought on by overcrowding leading to an outbreak of mountain pine beetle, ips beetle and other insects that have killed large numbers of trees over vast areas. In some ways it could be said that these insects are doing the work of forest thinning in the absence of fire. In many parts of the montane forest the beetle kill resembles a burn pattern, taking out a group of trees here and leaving others there.
An area burned in the High Park fire of 2012. Today, snowbrush (Ceanothus velutinus) is common there since its seeds can only germinate after it they are scarified, generally by wildlife.
However, there are many places where the subalpine forest has been reduced to nothing but a stand of dead trees, as far as the eye can see. But on closer examination, there is a tiny understory of forest already reestablishing in many areas. In 100 years these large areas of dead forest may be completely regenerated. But there is some concern that rising temperatures and a continual drying trend may not allow the subalpine forest to recover.
Water supplies in much of the West are dependent on Colorado’s high-altitude forests that trap and store snowfall. As snow in the cool sub-alpine forest begins to melt, it replenishes streams and rivers, including the Colorado River, which supplies water to 40 million people in seven western states.
The growth of cities in the American West has increased water consumption from the Colorado River and pushed this critical natural resource beyond its recharge capacity. It is possible that we could reduce some of this demand within the communities that we design and build by switching to a style of landscaping that is more appropriate for our region, thereby conserving water while restoring some of our state’s unique biodiversity.
Western native plants are adapted to the Colorado region’s bright sun, high altitude, and windy and dry conditions.
Here in the cities on Colorado’s Front Range, a region that typically gets 12–14 inches of precipitation per year, the average person uses 150 gallons of water per day. About 60 percent of residential water consumption goes to support landscaping. This amounts to approximately 90 gallons of water per person per day used to keep exotic landscapes on life support.
Colorado’s population in 1900 was 543,000. By 2019, the population had increased over tenfold to 5.7 million. Over the next 20 years, Colorado’s population is expected to grow by roughly 30%, increasing from 5.7 million in 2019 to 7.52 million in 2040.
Global climate change is already impacting the timing and the amount of water available in the state. Rising temperatures can lead to fewer, but more-intense precipitation events and can alter the ways in which plants grow. The transpiration process of plants pulls water from the soil and disperses it into the atmosphere. Transpiration increases as temperatures warm, which causes the plants to use more water and further dries out the soil.
Although our growing population and a changing climate will reduce available water, thus far, we have made virtually no effort to conserve water in landscaping. However, the rising cost of water is beginning to change how municipalities, developers and landscape designers are re-envisioning “regionally appropriate landscapes” that utilize native plants adapted to our high altitude, bright sun and dry climate.
Native landscapes can help wildlife survive during periods of drought. In the summer of 2020, during a prolonged drought, our gardens in Loveland, Colorado were thronging with birds and pollinators. Hummingbirds, which are usually found at higher elevations in summer, buzzed through our gardens in record numbers. Songbirds flocked to our gardens as well, seeking fruit, seeds and insects when many other sites were barren and dry. Hiking in the mountains to find wildflower seeds yielded nothing because many plants had flowered little, or not at all.
By late summer the dead standing timber in the high country, fanned by a hot dry wind, exploded into flames that burned over 665,000 acres. The resulting fires killed countless thousands of wild animals and caused $266 million in damages. 2020 was the costliest fire season in Colorado history until the following year when the Marshall fire broke this record in a single afternoon.
After the long summer’s drought of 2020, stress that resulted from fires and heavy smoke, and a sudden deep freeze in early September sent millions of birds in the Rocky Mountain West into a migration for which they were not prepared. Tens of thousands, perhaps hundreds of thousands, of birds were found dead in Southwestern states, where birds literally dropped from the sky.
With the growing threat of extinction facing so many species, today’s gardens need to be more than just pretty; they need to serve an ecological function. Thankfully, birds like the cedar waxwing are also protected under the U.S. Migratory Bird Treaty Act.
Holding one tiny bird while thousands of others flocked to our gardens under a smoke-filled sky.
A subsequent necropsy confirmed that the birds had died of starvation, unable to gain sufficient weight before migrating. As the effects of climate change increase occurrences such as this, it increases the need for us to subsidize the diet of our wild birds. A study undertaken by the Audubon Society says that 389 species, roughly two-thirds of all the birds in the U.S. are threatened with extinction or significant loss of habitable range due to climate change. Providing habitat within the landscapes that we design could make an enormous difference to their survival.
Full disclosure – shifting landscape practices, although perhaps the low hanging fruit, is not in itself enough to solve our water supply problems. It’s important to note that an estimated 50% of water used in the Colorado River Basin goes to raising cattle, and as much as 25% of our water nation-wide. While it could be argued that meat is the only sustainable food in our region because grazing animals do not destroy the native plant community in the same way that cultivation does, this does not represent the facts of the situation. Cattle are not drinking all this water. The water is used to grow crops to fatten cattle in crowded feed lots.
Solving the problems presented by climate change is, of course, not a simple matter. It will require two things that seem to be in extremely short supply, a widespread acceptance of demonstrable facts, based on scientific research, and a willingness to work with a broad base of stakeholders and partners including businesses, farmers, citizens, political leaders, and nature herself.
Many native plants have interdependent relationships with the insects that co-evolved with them, such as this two-tailed swallowtail (Papilio multicaudata)
The simple notion that it’s more beneficial and cost-effective to utilize native plants vs. laying down thousands of acres of irrigated turf would seem to be a foregone conclusion, but the notion is only slowly taking hold. Nonetheless, this conversion, if only out of the necessity of water shortages, is inevitable. But this is not an argument for austerity. This is rather an invitation to celebrate landscapes that are vibrant and interesting year-round, in a way that allows other beings, present and future, to do the same.
We have observed firsthand how dramatically and rapidly our local birds and pollinators recover when we grow native plants in our gardens. Celebrating our native biodiversity can restore our relationship to the land and may allow the new civilization that we have built on this land to continue, in harmony with nature.
Jim Tolstrup, author of “SUBURBITAT,” is the executive director of the High Plains Environmental Center, in Loveland, Colorado, a unique model for restoring nature where we live, work, and play.
The gardens at High Plains Environmental Center are virtually never watered, yet they are ablaze with color and thronging with wildlife throughout the season.
SUBURBITAT 