Bringing the Gardens to Light.
With more than a dozen distinctive gardens woven throughout Cheyenne Mountain Zoo's landscape, there's a lot more growing here than animals! On our virtual garden tours, you can learn all about themed gardens such as the Hummingbird Garden, Butterfly Garden and No Water Garden. Plus, check out the gardens incorporated into animal areas such as the African Rift Valley Garden and Asian Highlands Garden.
These tours include plants lists and growing tips for many plants, including some unique and under-utilized plants for the Rocky Mountain region.
The Zoo's horticulture team has spent years experimenting with a large number of plants to see which ones thrive in our Rocky Mountain climate. Now, with our virtual garden tours, you can take advantage of this expertise to learn more about the plants that share our home. Enjoy!
African Rift Valley Garden
Many visitors remember a time when, looking up the long, steep hill from the Zoo entrance to the giraffe herd, the only vegetation they saw was a line of Silver Maples. Today most of those trees are gone, and in their place, stands a mixed planting of grasses and shrubs.
Replicating the African Thornbrush Savanna
With Cheyenne Mountain Zoo sitting at about 7,000 feet, we faced a challenge in creating a landscape that resembled the African savanna for our African Rift Valley exhibit.
Plant Selection – Aesthetics
Looking across a thornbrush savanna you should see a canopy of thorny trees, a mid-story of shrubs, and a mix of grasses and flowering plants covering the ground. Savanna plants are adapted to low levels of rainfall and do not look lush or tropical so we needed to select plants with smaller leaves.
For our tree canopy, we could not use the Acacia trees that typically grow in Africa. And we opted not to used Honeylocust, even through they resemble Acacia trees, because large specimens do not transplant well on our site.
We selected small trees and large multi-stem shrubs like Silver Buffaloberry (Shepherdia argentea), New Mexico Privet (Forsteriana neomexicana), Honeysuckle (Lonicera sp.) and many species of Hawthorn (Crataegus sp.) because they accomplished these objectives. The selection of grass species provided a variety of textures in the height range from 2 to 10 feet tall.
Plant Selection – Function
Another important factor in our plant selection process was "will this be functional?"
- All plants to be placed in or near the exhibit were checked for toxicity.
- Many large 3" - 4" caliper specimens were planted with the hope that they would better withstand frequent animal contact.
- Because of the potential for animal damage, most of the plants inside the exhibit were selected because they can re-sprout from the root system and grow quickly. Most have also been tested previously on grounds for hardiness.
- Larger trees were placed in a few key locations to provide shade along parts of the path.
- Native plants were selected for non-exhibit hillside revegetation.
- Plants with similar water needs were grouped together according to irrigation zones.
- Large planting areas were designed to limit natural browsing and minimize use of hotwire.
Plant Selection – Planters
Cheyenne Mountain Zoo purchased several decorative planters to place along the elevated boardwalk. Often, potted plants struggle to survive the winter because, whereas plants in the ground are insulated by the surrounding soil, they are subjected to Colorado's extreme and irregular winter temperatures. Snowmound spirea (Spiraea nipponica ‘Snowmound), Asplenate Buckthorn (Rhamnus frangula ‘Asplenifolia’), Tidy Peashrub (Caragana ‘Tidy’), and various species of Shrub Roses (Rosa sp.) have survived many winters in these planters.
- Northern Catalpa (Catalpa speciosa) – used in our Okapi yard to simulate African Rain Forest
- Common Hackberry (Celtis occidentalis)
- Russian Hawthorn (Crataegus ambigua)
- Cockspur Hawthorn (Crataegus crusgalli)
- Douglas Hawthorn (Crataegus douglasii)
- Downy Hawthorn (Crataegus mollis)
- New Mexican Privet (Forestiera neomexicana)
- Manchurian Apricot (Prunus americanan var. manchurica)
- Purple Robe Locust (Robinia ‘Purple Robe’) – used away from animal exhibits due to it’s toxic seeds
- Prairie Cascade Willow (Salix 'Prairie Cascade')
- Indigo Bush (Amorpha fruticosa)
- Siberian Peashrub (Caragana arborescens)
- Fernbush (Chamaebatiaria millefolium)
- Peking Cotoneaster (Cotoneaster lucidus)
- Apache Plume (Fallugia paradoxa)
- Honeysuckle (Lonicera sp.)
- McKay's White Potentilla (Potentilla fruticosa 'McKay's White')
- White-stem Gooseberry (Ribes inerme)
- Woods Rose (Rosa woodsii)
- Silver Buffaloberry (Sheperdia argentea)
- Big Bluestem (Andropogon gerardii)
- Silver Bluestem (Andropogon sacharoides)
- Feather Reed Grass (Calamagrostis x acutiflora 'Karl Foerster')
- Plumegrass (Erianthus Ravenna)
- Autumn Light Miscanthus (Miscanthus sinensis 'Autumn Light')
- Maiden Grass (Miscanthus sinensis 'Gracilimus')
- Rehbraun Switch Grass (Panicum virgatum 'Rehbraun')
- Prairie Sky Switch Grass (Panicum virgatum 'Prairie Sky')
- Little Bluestem (Schizachyrium scoparium)
- Prairie Cordgrass (Spartina pectinata)
- Ponytails (Stipa tenuissima)
- Giant Sancton Grass (Sporabolis wrightii)
- Foxtail Lily (Eremerus sp.)
- Torch Lily or Red-hot poker (Kniphofia sp.)
- Partygirl False Mallow (Sidalcea 'Partygirl')
Asian Highlands Garden
Asian Highlands was constructed in 1995-96. Instead of replicating the Siberian Tiger, Palis Cat, and Amur Leopard's natural habitats, the landscape architect decided to focus on plants from Asia, Siberia, and the Amur region that had horticultural value.
The initial idea was that a visitor could walk though Larch and Ginkgo forests to appreciate the beauty of these two species.
- European Larch (Larix deciduas) is hardy to zone 4. It is unique because the tree bears cones, yet loses its needles in the fall after they turn yellow.
- The Ginkgo (Ginkgo biloba) is also hardy to zone 4 and is best known as an herb with medicinal value that is good for depression, memory loss, headaches and tinnitis.
- In the spring of 2002, we planted two Amur Maackii (Maackii amurensus), a small tree with silvery new foliage that boasts unique fragranced white blossoms in mid-summer. Several of these Maackii amurensis were also planted in the African Rift Valley project and survive to today, though the two planted in Asian Highlands do not.
- Lacebark Elm (Ulmus parvifolia) has been an interesting tree because of its multicolored bark. It continues to struggle due to winter kill, probably related more to winter drought than to an issue of hardiness. It is often so late to leaf in spring that we have to check it carefully to know it is still alive.
- Dawn Redwood (Metasequoia glyptostroboides) is a deciduous tree with evergreen-like leaves and a uniform conical habit. According to fossil records, the Dawn Redwood was originally native to North America but was thought to be extinct for 15 million years until it was rediscovered and reintroduced in the 1940s.
As the shrubs in this area have matured, this garden has taken on a lush feel.
- The plant that has drawn the most attention is the Yellow Groove Bamboo (Phyllostachys aureosulcata). Traditionally, bamboo hasn't been considered a hardy plant, but recent breeding efforts have developed varieties that grow well in our conditions. In our garden, Yellow Groove reaches five to six feet tall and remains evergreen most of the year. This Bamboo does need to be watered in the winter or it may experience considerable dieback.
- The Star Magnolia (Magnolia stellata) originally planted in the garden has, over the years, gone by the wayside; again this is likely due to dry winter conditions. This plant needs regular winter watering to perform well.
- Common Witchhazel (Hamamelis virginia) also has fragrant flowers but draws less attention because they are small, yellow, and open in November and December. This shrub has performed well despite being zone 5.
- Another plant of interest is Siberian Spirea (Sibiraea laevigata). This five foot by five foot shrub was featured as a 2002 Denver Botanic Gardens/Colorado State University Plant Select plant. Over the years this plant has survived though it has grown only modestly.
- Pink Dawn Viburnun (Viburnum x bodnantense 'Dawn') has very fragrant pink flowers in early spring. This variety is less hardy than other Viburnum species like Nannyberry, Wayfaring Tree, Snowball Bush, American and European Cranberrry, which often have non-fragrant white flowers, wildlife-attracting red to black berries, and bright red fall color. Despite its more tender nature, these Viburnums have performed well and receive much comment when in bloom.
The Asian Highlands garden is primarily woody plants but there are a few perennials worth highlighting.
- Fire Tails (Persicaria amplexicaulis 'Speciosa'.) draws much favor in late summer as the red and pink flowers cover the plant.
- Caesar's Brother Siberian Iris (Iris sibirica ‘Caesars Brother’) is hardy to 9000 feet and boasts large deep purple blooms in May and June.
- Sweet Woodruff (Asperula odorata) is a wonderful shade loving perennial groundcover that has spread itself around the garden. It has fragrant white flowers in May, fragrant foliage, and makes a wonderful companion plant to spring bulbs.
The Butterfly Garden dates back to the summer of 1996. It was the first garden designed and constructed by Horticulture Curator, Bob Chastain, who is now our President/CEO. Visitors can experience the garden from the patio at Moose Lake Lodge or along the main path to Grizzly Grill.
At the time this garden was developed, existing Willows and Cottonwoods bordered the garden and presented a challenge by drawing most of the available soil moisture and nutrients away from the rest of the garden. Though these trees are long gone, the raised bed originally created as a response to these trees still exists, and it has been replicated in adjacent planting beds as we developed our Plant Select Garden in 2010.
Some plant highlights in the garden are:
- Moonshine Yarrow (Achillea ‘Moonshine’) is a hardy perennial that attracts butterflies. It has attractive silver foliage and it is less invasive than many other varieties.
- Summer Beauty Ornamental Onion (Allium ‘Summer Beauty’) attracts attention because most people don't expect to find ornamental onions in a butterfly garden.
- False Spirea (Caryopteris ‘Blue Mist' and C. ‘Dark Knight')are the most popular shrubs in the garden and have blue flowers that last most of the summer. This plant is hardy to 9,000 feet but may need to be pruned each sping due to winter dieback. Beware that bees are fond of this plant, so it is not recommended to locate this near a deck or main entry.
- Royal Red Butterfly Bush (Buddleia ‘Royal Red’). Over 45 cultivars of Buddleia davidii are being grown in the United States. Cheyenne Mountain Zoo relies heavily on 'Royal Red' because of the nearly ten different types of Buddleia that have been planted on grounds it has been a consistant performer.
Colorado Life Zones Garden
The Colorado Life Zones or Transition Garden depicts five of the major bioregions in Colorado. This garden was planted with the support of The Broadmoor Garden Club and the Colorado Tree Coalition.
From left to right, the hillside progresses from grasslands to Alpine Tundra. In Colorado, the bioregions are generally found at these elevations:
- Grasslands: under 6,000 feet
- Shrublands: 6,000 to 8,000 feet
- Montane Forest: 8,000 to 10,000 feet
- Subalpine Forest: 10,000 to 11,400 feet
- Alpine Region: above 11,400 feet
Many native evergreens are represented in the garden including:
- Bristlecone Pine (Pinus aristata) occupies dry, windy, south-facing slopes and can be found most abundantly above 9,000 feet in its natural ecosystem. Bristlecone Pine, also called Foxtail Pine, can live up to two thousand years. Their long-lived needles supply a steady source of nutrients to carry them through rough periods and their slow growth creates denser wood that defends the trees against pest attacks. Bristlecone Pines have short needles with white resin dots that resemble snow and make them easy to identify.
- Limber Pine (Pinus flexilis) has soft grayish-blue needles that form in tufts along thin pliable branches. These flexible branches give the tree its common name and wind tolerance. In its natural ecosystem, Limber Pine occupies dry, windy, south-facing slopes and can be found most abundantly above 9,000 feet.
- Ponderosa Pine (Pinus ponderosa) is found on south-facing slopes and has long needles in mixed clusters of two or three.
- Douglas Fir (Pseudotsuga menziesii) is not a true fir and is distinguished by its cones that hang downward rather than upward like true firs and by the bracts that look like a snake's tongue and jut out between the cone scales.
- Colorado Blue Spruce (Picea pungens) varies in shades of greens and blues based on plant genetics, soil mineral composition, and other factors. Picea pungens glauca is often used to denote those with more blue tones.
Scattered along the hillside are shrubs from the different ecosystems.
- Apache Plume (Fallugia paradoxa) grows five foot by five foot and produces quarter-sized white flowers and wispy seed plumes in late summer.
- Skunkbrush (Sumac trilobata) has attractive red to orange fall color, a distinct odor, and fuzzy maroon fruits that were used by Native Americans in many recipes.
- Chrysothamnus nauseosus, which grows in the sagebrush shrublands, is known in Colorado as Rabbitbrush and in New Mexico as Chemisa. Masses of yellow flowers top this shrub in August and September and contrast nicely against its blue-gray foliage.
- Tucked behind the aspens are a group of Red-berried Elder (Sambucus pubens). Elders grow in moist sites, have white flower clusters, and bright red berries.
Many interesting perennials and grasses can be found in the sections of the garden closest to Aquatics and above goats.
- Big blustem (Andropogon gerardii) grows five to six feet tall and turns reddish after the first frost. It is also called Turkeyfoot because the seed heads divide into three sections and resemble a turkey's foot.
- Little Bluestem (Schizachyrium scoparium) is a closely related plant that also turns russet red in the fall, but stays under two feet tall.
- Rattlesnake Master (Eryngium yuccifolium) has yucca-like foliage and small white flower clusters that appear from July to September.
- Purple Prairie Clover was once classified as Petalostemon purpureum, but is now referred to as Dalea purpureum. This two- to three-foot tall plant is in the legume family and produces bright purple cylindrical flower heads.
- The compass plant (Silphium laciniatum) is a long-lived perennial that produces a four- to seven-foot tall stalk with up to 100 bright yellow flowers that take a month to fully open.
- A close relative, Silphium perfoliatum, which is commonly called Carpenter or Cup-plant, grows six to eight feet tall and has opposite leaves that join at the bottom forming a cup.
This garden in front of Aquatics building was first planted to attract hummingbirds in the early 1990s. In the summer of 2001 a water line broke underneath the garden and nearby sidewalk. To fix the problem it was necessary to excavate the entire area. The garden was redesigned and replanted in a naturalistic manor to blend with the Zoo's mountainside setting.
In designing a water feature for the new garden, the horticulture team took a field trip to nearby Cheyenne Canyon and walked the creek to see how water flows and travels over rocks. The team returned with a clear picture and built the water feature to closely resemble a mountain steam. A log bridge across the ’creek’ and river rock pathways were also added. After the water feature and path were constructed, the large shrubs were placed for structure.
- The backbone of the garden is Butterfly Bush (Buddleia sp.), which provides nectar for birds as well as butterflies.
- Golden Current (Ribes aureum) commonly referred to as, is a drought tolerant plant with spicy smelling, yellow, tubular flowers in May.
- The other significant shurb in the garden is Beautybush (Kolkwitzia amabilis). It is a little known plant and seldom used in Colorado Springs, but it offers exfoliating bark, reddish fall color, and attractive flowers. Beautybush has an abundance of light pink blooms that appear in spring on last years stems before the shrub leafs out, so they are very showy, much like a lilac or forsythia.
As you can tell by the number of trees and shrubs listed, this garden consists primarily of perennials. Over the more than ten years that this garden has been in place a number of its original perennial plantings have gone by the wayside, and additional perennials have been added, So if you visit the garden you will notice some discrepancies from the list below.
- Maltese Cross (Lychnis chalcedonica) is a short lived perennial for any hummingbird garden. The birds are attracted to the small cross-shaped red flowers that sit in clusters atop two feet tall stems.
- Another must for the Rocky Mountain region are the different types of penstemons. This group of plants is so valued for its drought tolerance, lengthy and showy flower display, and nectar supply that the entire genus was named the 2001 Perennial of the Year by Great Plants for the Great Plains.
- The Rocky Mountain Penstemon (Penstemon strictus) has two- to three-foot spikes of lavender blooms.
- Pineleaf Penstemon (Penstemon pinifolius) is a compact plant with needle-like leaves and scarlet flowers.
- Red Rocks Penstemon (Penstemon x mexicale 'Red Rocks') was named a 1999 Plant Select® winner for its bright rose flowers and tolerance for a wide range of soil conditions. This perennial flowers profusely throughout the summer but tends to require replacement after a few years as it tends to be short-lived. Please visit our Plant Select® Garden expandable on this page to learn more about the Plant Select® Garden Program.
- Whipples Penstemon (Penstemon whippleanus) is a common mountain native hardy to 12,000 feet with wine-purple flowers.
- Firecracker Penstemon (Penstemon eatonii) is an interesting plant because of its growth habit. It is slow to emerge in the spring, but almost overnight the wispy plant will shoot up two to three feet and generate bright scarlet trumpet-shaped flowers.
- Denver Gold Columbine (Aquilegia chrysantha 'Denver Gold') is a showy yellow columbine featured in the 2001 Plant Select program.
- Leopard Plant (Ligularia 'The Rocket') was salvaged and transplanted from the existing garden. The variety of Ligularia loves moist sites and has impressive yellow flower spikes that can reach five to six feet tall.
- Several varieties of Lupine including Lupinus 'Gallery Blue', 'My Castle', and 'Gallery Red' are planted. These three varieties in the genus Lupinus are all hardy to 9,000 feet and produce either red or blue pea-like flowers in May and June.
- Swamp Milkweed (Asclepias incarnata) is a zone 5 plant that produces showy dusty pink flowers in late summer. Milkweeds also serve as a host and nectar plant for many types of butterflies.
- Many different types of Bee Balm (Monarda) were planted in this garden including Monarda 'Marshall Delight', 'Jacob Cline', 'Petite Delight', and the native Monarda fistulosa. Beebalm is in the mint family so it has fragrant leaves and tends to form clumps that spread continuously.
Lion's Lair Garden
The plants in Lion's Lair were selected because the combination of mid-sized shrubs with short grasses creates an under-story/over-story multidimensional effect that resembles what you might see in an African savanna.
Before the renovation project in 1997, this area was bluegrass sod. Now it contains a mix of native and non-native grasses, including:
- Blue Avena or Blue Oat Grass (Helictotrichon sempervirens), is easy to find in nurseries or garden centers because of its striking blue foliage and compact size. This plant surrounds the dry water hole in the center of the garden.
- Little bluestem (Schizachyrium scoparium), is a medium-sized warm season bunch grass that naturally occurs in elevations between 3,500 feet and 8,000 feet.
Behind the grasses are the mid-sized shrubs.
- White Potentilla (Potentilla fruticosa ‘McKay’s White’) line the walkway from giraffes and are scattered throughout the garden.
- To the left you will see a thorn-covered Cockspur Hawthorn (Crataegus crusgalli). Considered large shrubs or small multi-stemmed trees, these specimens have dark glossy green leaves, small white spring flowers, bright red fall berries, and showy orange to red fall color.
- New Mexico Privet (Forestiera neo-mexicana) has proven to be a durable, drought tolerant shrub and is considered by some to be an excellent Aspen alternative for lower elevations.
- The other large shrub that looks similar to the privet in size and shape is Buffaloberry (Shepherdia argentea). You can identify Buffaloberry by its silvery-gray foliage and orange-red berries compared to the green foliage and blue berries on the privet.
No Water Garden
Colorado is a high desert that does not have an unlimited supply of water. Colorado's water supply comes from mountain lakes and riparian areas and is replenished by rainfall and melting snow. Without precipitation, those sources are not replenished, and habitats are destroyed. Riparian corridors make up only five percent of Colorado ecosystems, yet 95 percent of wildlife is dependent upon them for survival. The Colorado River, a main source of water, rarely reaches the ocean anymore because Colorado and surrounding states collectively draw down nearly the entire repository of water.
Currently in Colorado Springs, as in other of Colorado’s urban areas, 40 to 60 percent of potable water is used on landscapes. Compounding the water usage is Colorado’s ever-growing population. Colorado Springs alone has grown from a city of 200,000 to nearly 500,000 in approximately 20 years. This translates into an increase of millions of gallons of additional water used on landscapes.
As the demand on our existing water delivery system has continued to grow in Colorado Springs, additional sources of water have been secured and an expansion to our existing water delivery system is in the process of being constructed.
While the development of additional water sources will secure the water we need as a growing population, the development of those resources will bring an increased burden on the natural ecosystem and an increased cost for that water, providing an additional incentive to reduce water-consuming landscapes in favor of water-efficient landscapes.
In addition to having a limited water supply, Colorado experiences periodic drought. In 2002 Colorado faced its worst drought in 40 years and the City of Colorado Springs enacted mandatory water restrictions with the goal of reducing consumption by 20%. As early as January 2002, Cheyenne Mountain Zoo began to evaluate the situation and discuss options for water conservation. The Zoo developed a water conservation plan and succeeded in dropping its own water consumption. Compared to 2001, in 2002 the Zoo's water usage dropped 59 percent in March, 54 percent in April, 19 percent in May, 12 percent in June, 27 percent in July, 33 percent in August, 42 percent in September and 65 percent in October. To this day Cheyenne Mountain Zoo continues to voluntarily adhere to the 2002 water restrictions.
Emergence of the No Water Garden Concept
In addition to adhering to strict water restrictions, the Zoo developed and implemented a bold experiment for a ‘No Water’ Garden. Through the ‘No Water’ Garden concept, the Zoo hoped to change attitudes and practices of both professionals and home gardeners about what is possible in the western landscape.
At that time the ‘Xeriscape’ concept was a part of the average garden vocabulary. Xeriscape principals educate people on how to include more low water use plants in yards and gardens. However, the "No Water" Garden concept provided the opportunity to take water conservation several steps further; exploring the possibility of growing plants that require no supplemental water.
In early April 2002, the Horticulture department at Cheyenne Mountain Zoo planted a "No Water" Garden around four existing Russian Hawthorn trees in a bed between our two parking lots. Aside from the trees, little grew in the area due to poor soil conditions, the radiant heat from the surrounding asphalt, and the lack of a convenient water source. In years past, organic mulch had been added to the area; otherwise no regular maintenance had been performed.
The Zoo selected a mix of native and non-native shrubs, perennials and grasses ranging in size from two and one quarter-inch to five-gallon pots. At the time of planting the entire bed was thoroughly watered. And then we walked away.
Detailed Plant Lists and Success Rates
These spreadsheets detail what was planted in the garden each year and the survivability of the materials through Fall 2011:
- Spring 2002 Planting
- Fall 2002 and Spring 2003 Plantings
- Fall 2003 and Spring 2004 Plantings
- First Year Survival Results
Summary of the No Water Garden Results
Over the years, the No Water Garden received significant publicity, with local print, television and radio coverage; a Conservation reward in 2003 from the Association of Zoological Horticulture; and presentations on the "No Water" Garden at the 2003 and 2004 Peak to Prairie Landscape Symposiums.
In addition to the No Water Garden at the Zoo, Perennial Favorites in Rye, the City of Aurora, and the El Paso and Gilpin County Cooperative Extension Offices started similar gardens.
One of the goals of the No Water Garden had been to develop a list of plants that can survive or even thrive in drought conditions and be attractive in the landscape. Over the period of 9 years approximately 100 species were trialed. In fall 2011 the gardens were evaluated with the intention to finalize a list of recommended species. At that time it was noted that a number of shrubs trialed in the garden had begun to overgrow some of the perennials and the trial results were in jeopardy of being skewed as a result. As such the results recorded in Fall 2011 conclude the plant trial, though the garden continues to live on. Below is a summary list of recommended species based on this trial, as well as a brief description of our experience with each plant:
Seven Secrets to Our Success!
1. Plant early or late to allow plants to take advantage of natural rainfall and cooler temperatures. This may mean planting earlier or later than is commonly recommended. If you can dig the hole, you can install the plant. It is not uncommon for the Zoo's horticulture staff to plant between snowfalls in March and April, and October and November. Just remember that plants not grown locally, or those grown in a greenhouse must be "hardened off" or they will be frost damaged.
2. Water in the plants thoroughly before and after you put them in the ground. Let the roots soak up as much water as possible. This might mean placing them in a tub of water for several hours before you plant.
3. Pick the right plants. Not every species can survive with low moisture levels. Use the summary list of successful plants we created from actual "No Water" trial gardens. Species that have small leaves, blue or gray foliage, root structures specially designed to store water, or deeply rooted plants will generally be more successful.
4. Plant at the correct depth. If plants are set too high they will be exposed to the low-humidity air and changing air temperatures. If they are set too low they will not be able to get oxygen (especially in clay soils).
5. Make sure you mulch the plants to conserve moisture. Mulch early to conserve spring moisture. Mulch depths of 2" tend to work well for perennials and up to 4” depth tend to work well for woody plants.
6. Use rocks, walls, or other structures around the plants to shade the roots and trap moisture in the soil. We found that this benefit outweighed our concerns about heat reflecting from the rocks and damaging the plants.
7. Watch your plants to see how they respond to short- and long-term water shortages.
Think about whether or not you should amend the soil. Cheyenne Mountain Zoo had high survival rates without any soil amendment. Amendments help by increasing availability of nutrient and providing better water retention. But what if your plants don't need the extra help? Native plants have proven they can survive and thrive without any help from man. Many professionals are questioning the wisdom of amending all soil types. The one exception in Colorado would be clay soils.
Plant Select® Garden
The Plant Select® Garden Program is a cooperative program administered by Denver Botanic Gardens and Colorado State University together with landscape and nursery professionals throughout the Rocky Mountain region and beyond. The purpose is to identify and test promising new plants for the region for possible introduction into the trade.
Because the staff maintains gardens across 65 developed acres, it is important to have an area dedicated to testing new plants. In 2003, the horticulture staff built a trial bed at the Zoo's greenhouse to trail these plants. Plants were monitored for water requirements, hardiness, and resistance to pests.
In Spring 2010 the Zoo developed a Plant Select® Demonstration Garden that is accessible to the public just south of the Grizzly Grill. The garden features a wide variety of plants that are ideally suited to our climate, with the focus being Plant Select® plants. This garden contains the following Plant Select® plants:
Sonoran Sunset® Hyssop (Agastache cana 'Sinning')
Sunset® Hyssop (Agastache rupestris)
Denver Gold® Columbine (Aquilegia chrysantha)
Colorado Desert Bluestar (Amsonia jonesii)
Filigree Daisy (Anthemis marschalliana)
Mock Bearberry Manzanita (Arctostaphylos x coloradoensis)
Panchito Manzanita (Arctostaphylos x coloradoensis)
Blonde Ambition Blue Grama Grass (Bouteloua gracilis 'Blonde Ambition’)
Korean Feather Reed Grass (‘Calamagrostis brachytricha’)
Baby Blue Rabbitbrush (‘Chrysothamnus nauseous var. nauseous’)
Spanish Gold® Broom (‘Cytisus purgans’)
Fire Spinner® Ice Plant (‘Delosperma 'Broncoensis')
Red Feathers (Echium amoenum)
Bluestem Joint Fir (Ephedra equisetina)
Kannah Creek® Buckwheat (Eriogonum umbellatum var. aureum 'Psdowns')
Seven-Son Flower (Heptacodium miconioides)
Regal Torchlily (Kniphofia caulescens)
Kintzley’s Ghost® Honeysuckle (Lonicera reticulata)
Silverheels Horehound (Marrubium rotundifolium)
Little Trudy® Catnip (Nepeta 'Psfike')
Silver Blade® Evening Primrose (Oenothera macrocarpa subsp. incana)
Avalanche White Sun Daisy (Osteospermum ‘Avalanche')
Pikes Peak Purple® Penstemon (Penstemon x Mexicali ‘Pikes Peak Purple’)
Red Rocks® Penstemon (Penstemon x mexicali ‘Red Rocks’)
Shadow Mountain® Penstemon (Penstemon x mexicali 'Psmyers')
Bridges' Penstemon (Penstemon rostriflorus)
Purple Winter Savory (Satureja montana var. illyrica)
Red Birds In A Tree (Scrophularia macrantha)
Giant Sacaton (Sporobolus wrightii)
Partridge Feather (Tanacetum densum ssp. amani)
Valley Lavender® Plains Verbena (Verbena bipinnatifida)
Alleghany Viburnum (Viburnum x rhytidophylloides 'Alleghany')
Primate World Garden
Primate World was originally planted with Aspen (Populus tremuloides) and other native and non-native species. Over time, the garden has taken on a lush and tropical feel. Many of the plants have large and compound leaves. Much like Asian Highlands, this is a trial area for new and/or underutilized species.
Kentucky Coffeetree (Gymnocladus dioicus) and Ohio Buckeye (Hippocastanum glabra) are both incredible trees that have found a home here. Unfortunately, they grow slowly and are often irregularly and sparsely branched when young, so they get passed by in nurseries by consumers.
- Kentucky Coffeetree has pinnately compound leave and showy white flowers. They are dioecious, so the male and female flowers reside on separate trees; only the female trees will bear the large mahogany colored seed pods.
- Ohio Buckeyes have palmately compound leaves and yellowish green flowers. A non-edible fruit forms and is protected by a spiny shell.
Ashleaf Spirea (Sorbaria sorbifolia) grows five to seven feet tall and has white flowers in late summer. It is extremely hardy and has proven to be very resilient inside animal enclosures.