Lately, it seems there has been an ever-growing buzz in the media regarding native plants. We here at Outdoor Design Group appreciate this budding interest in native plants, but we have a long-established love and interest in utilizing native plants in the landscapes we design.
The blooming enthusiasm for North American, as well as regionally specific native plants got us thinking about how to advise native plant newbies to get started with these plants in their gardens and landscapes.
If you’re not sure why you should include native plants in your Colorado landscape (or any landscape anywhere on earth for that matter), here are a few reasons:
They’re adapted to the water, light, soil and temperature fluctuations and constraints of your area.
They’re adapted to the animals and insects of your region, providing food & shelter for the native fauna, as well as being generally more resistant to browsing by insects and other animals.
Utilizing them in your landscape design helps anchor your property in the ‘place’ of your region. Put another way: Why grow plants that can be grown in New York, London or Tokyo? Why not grow plants that show your interest and love of the region you live in?
This brings us to a quick list of the 14 Easiest Colorado Native Plants to include in your landscape.
Before we get to the list, we must mention one big caveat: the term “native” plant is somewhat subjective. What area is one referring to when they say, “native to a certain region”? North America? The Great Plains? The Rocky Mountains? The state of Colorado? Only within a 50-mile radius of your location? The native plants we are presenting on the following list are mostly native to the Rocky Mountain region, while some on the list are more broadly native to North America.
The other thing we should mention is that while native plants have various and obvious good reasons to be utilized in one’s landscape, there are many non-native plants that can be good and ecologically appropriate choices for a certain landscape as well.
It’s worth mentioning that even if a plant is native to your region or state, that doesn’t mean that these plants will do well in every situation your yard presents. For example, aspen trees are native to the state of Colorado and surrounding Rocky Mountain states, but only are they native to the mountains and foothills. Aspen trees often struggle on the hotter drier front range cities east of the mountains where Denver is located. And just because a plant is a “native” does not mean that it won’t perform like an invasive weed. An example of this is Virginia Creeper (Parthenocissus quinquefolia) which is a North American native vine but reseeds readily in many areas and can be difficult to remove.
It all depends on many factors! Now, on to our list of great native plants to grow in Colorado:
TREES:
– Blue Spruce (Picea pungens). Sporting a conical and classic Christmas Tree form, this evergreen tree has moderate water needs so should be thoughtfully placed if your property is hotter & drier. There are many cultivars to choose from. This is one evergreen tree that might do better in an irrigated lawn.
-Bristlecone Pine (Pinus Aristata). This is a tough pine tree that is native to higher elevations but can do well in some locations at lower elevations. It can have an irregular and shrubby form. Like most pines, it has low water requirements.
Bristle Cone Pine
-Pinon Pine (Pinus edulis). The native range of this pine is generally southern Rocky Mountains of Colorado and New Mexico. This is a good pine tree for hotter and drier locations. Its form is somewhat bushy and rounded. And the nuts are edible!
-Cottonwood (Populus spp.). There are several types of cottonwoods to choose from. They are all tough and dependable, but they don’t live very long. And some varieties have a suckering habit. They prefer moist soils, and they grow fast. They can be messy as well, so best for informal areas or larger properties.
-Bigtooth Maple (Acer grandidentatum). One of the few maples that can survive drought type conditions. Related to sugar maples, this native of the Rocky Mountain region has orange-red fall color and is more adapted to Colorado’s alkaline soils so it shouldn’t suffer chlorosis like other maple trees. This tree maxes out at 20-30 ft. tall and is more shrub-like (with multiple stems) and not a classic shade tree shape like some more popular and common (but not suited for Colorado soils) maple trees sold in local nurseries.
Bigtooth Maple, fall color
SHRUBS:
-Currants (Ribes spp.). There are several native varieties of currants to choose from. One of our favorites is Crandall Clove Currant, Ribes odoratum ‘Crandall’
-Yucca (Yucca spp.). Yuccas are tough plants that are well adapted to most areas of Colorado and the surrounding states. Some species and varieties are less cold hardy than others. If you’re bored with the local native Soapweed Yucca, you could try Banana Yucca, Beaked Yucca or even Dollhouse Yucca. If you’re worried about the stiff spiky leaves, you could opt for Yucca filamentosa, which has spiky tips, but the leaves are less stiff. It is native to the Southeastern United States, so they’re less drought tolerant than other yuccas.
Adam’s Needle Yucca
-Agave (Agave spp.). Agaves bring stunning architectural interest to the garden with their sword-like leaves. Most agaves that are native to North America are not cold tolerant enough to be grown in Colorado, but there are at least 3 species that can handle winter in greater Denver and other Front Range areas, as well as The Grand Valley on the Western Slope. Any areas that are at least USDA zone 5 or higher. As with cacti, keeping the agave roots on the dry side during winter will help them survive the cold. One of the cold hardiest Agaves is the Harvard’s Agave, Agave havardiana.
-Opuntia Cacti (Opuntia spp.). If you can get past the spines, you will be rewarded with amazing flowers in late spring. Not every Opuntia cacti variety is cold hardy enough for all of Colorado. But a few varieties are hardy to zone 5 and are great additions to your xeriscape, providing a stunning floral display in spring and interesting shapes and forms all year round. And if the spines are a roadblock to enjoying these North American natives, there are some cultivars with less spines. Cacti will be happier if their roots can be in mostly dry and well-drained soil throughout the winter.
Opuntia, Chocolate Princess cultivar
Perennials & Ornamental Grasses:
– Native Blanket Flower (Gaillardia aristata). Blanket Flower is a wonderful North American native flower that provides eye-popping yellow, orange and red color when it blooms in late summer to early fall.
– Penstemon (Penstemon spp.). There are so many Penstemon cultivars and nativars to choose from, its hard to pick just one. Some live longer than others. Two of our favorite penstemons (how can we pick just 2?!?) are Penstemon pseudospectabilis, and Penstemon pinifolius.
Pineleaf Penstemon
– Desert Four-O’-Clock (Mirabilis multiflora). The Desert Four-o-clock is a low-growing perennial that is very drought tolerant. It grows and spreads fast during summer with a display of bright magenta-pink blooms, but it is an herbaceous perennial, so it “dies” back to the ground every fall, like peonies.
– Columbine (Aquilegia spp.). A classic perennial plant with many varieties to choose from. These plants generally do better in cooler & wetter conditions. It’s best to save them for the part sun / part shade areas of your property.
– Blonde Ambition Grama Grass (Bouteloua gracillis ‘Blonde Ambition’). This nativar, discovered by the late David Salman of High Country Gardens, has exploded in popularity, almost to the point of being overplanted. But it’s popular for good reasons. It is tough, drought tolerant and visually striking in the fall when it sends out its one-sided seed heads that catch the sunlight in the waning days of autumn.
Blonde Ambition Grass
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
After a long hot summer in Colorado, the fall season may seem like a time to forget about your yard or garden and start focusing your attention indoors. But fall is a great time for some low-water perennial plants to look their best and shine in your xeriscape garden. The following list of plants take center stage during the fall season, and keep your landscape looking great beyond the arrival of the autumnal equinox.
Anemone (various species and cultivars)
Anemones are a great plant for the shadier areas of your landscape. While not as drought tolerant as the other plants on this list, they grow very well with afternoon shade and a medium amount of water.
Anemone
Tall Sedums, various cultivars
The tall sedums are a classic addition to the fall blooming garden. With low to average water needs, they are perfect for most xeriscape gardens.
This cousin of the popular groundcover plant Orange Carpet California Fuschia (also a good late bloomer) has similar dazzling orange trumpet shaped flowers that pollinators adore.
Hummingbird Flower
Furman’s Red Salvia, Salvia greggii (several species and cultivars available in the Salvia genus)
There are so many different and wonderful plants in the Salvia genus that are remarkable additions to your low-water landscape. Furman’s Red Salvia is one plant we have raved about many times, and it never fails to keep us captivated by its lovely and numerous red blooms that drape these plants from summer heat to fall frost. One note of caution on this plant would be the hardiness. It is rated as only hardy to zone 6, so be careful where you place it. A warmer micro-climate location in your landscape would be best.
Furman’s Red Salvia
Blanket flower, Gaillardia (various cultivars available)
While the blanket flowers bloom more profusely in the heat of the summer, they continue to bloom into fall, bringing their brilliant shades of yellow, orange and red into the shorter days of autumn.
Blanket Flower
Goldenrod, Solidago (various species)
Solidago rugosa ‘Fireworks’ is the plant pictured here. Who wouldn’t mind this kind of fireworks in their fall landscape? This North American native will grace your garden with many panicles of bright yellow flowers. While not as tolerant of drought as some other plants on this list, it is fairly adaptable to most conditions in Colorado. This plant has been unfairly blamed for hayfever and allergies in the past, but scientists now tell us that Goldenrod is not the cause of your fall allergies. It is likely caused by other plants such as ragweed.
Goldenrod
Plumbago, Ceratostigma plumbaginoides
Plumbago is an indispensable groundcover. It does well in dry shade, and that is the type of conditions we typically place it in. However, we are finding it seems to be adaptable to sunnier locations as well. The blue-violet flowers that appear on this plant in late summer are eye-catching, as is the red-orange fall color of the foliage as autumn grows cooler.
Plumbago
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
The landscaping on commercial sites may be low on a business owner’s list of priorities for their property. But you should not underestimate the positive influence an attractive landscape can have on potential clients. With this in mind, here is a list of ten issues to consider for choosing the right plants to keep your property’s landscaping looking and functioning at its best.
Non-Invasive
Some very hardy plants would be great choices for commercial landscapes if not for their tendency and ability to invade and spread where they are not wanted. This may happen via seedlings or by creeping rhizomes (horizontal underground stems that can send out new roots and shoots). Luckily, here in Colorado and the Inter-Mountain West, our growing climate is challenging for many invasive plants that have ravaged milder climates in North America. However, there are some plants you should never allow to take root in Colorado due to their invasive nature. For a list of plants see: http://www.invasivespeciesinfo.gov/unitedstates/co.shtml; http://www.ext.colostate.edu/ptlk/2041.html
Blonde Ambition Grama Grass and English Lavender
Disease Resistant
Nobody wants to spend extra money or time dealing with or replacing diseased or dying plants. Avoid choosing plants that are easily susceptible to attack from disease or pests.
Long Lived
Along the same lines of replacing diseased plants prematurely, nobody wants to spend time and money replacing plants that live short lives. The cost of purchasing and installing landscape plants is significant, so it is wise to choose plants that will stand the test of time.
Adaptable to various exposures
The location you are planting on your property may currently be in any degree of exposure from full sun to full shade. But conditions may change in the near future. Will a new building or new trees be placed on the neighboring property? Conversely is a structure or tree slated to come down, creating a new pocket of full sun? Picking plants with higher adaptability to various exposures will ensure success for your landscape.
Adaptable to various soils
The soils in my area are typically heavy in clay with a high (alkaline) pH. This is one more challenge to add to the list of issues that face landscape plants. For best success and longevity, choose plants adapted or adaptable to the soil conditions on your property.
Adaptable to variable moisture levels
You may be familiar with desert plants and you may be familiar with rainforest plants. These two extremes of ecology illustrate the wide variability of climate that plants live in. Your landscape likely falls somewhere in between these extremes. However, even in the most average commercial landscape, we might find wide degrees of moisture and irrigation levels. Having plants that can handle these extremes will help ensure your landscapes do well.
Drought Tolerant
Although nearly all municipalities require automatic landscape irrigation, it is good if the plants you specify for a site are truly drought tolerant.
But on the flip side, some plants that are considered very low water plants may be more difficult to establish on a commercial site due to over watering. Many but not all native plants fall in this category. They are more fussy about soils and drainage. They may need to be ruled out of the “set it, and forget it” situation that many commercial clients may seek. But if you have the time or the staff to work with some very low water plants during their establishment time, they can eventually become great components of your drought tolerant landscaping. The easiest plants to use in your landscape will be adaptable to varying soil moisture levels.
A variety of perennials and shrubs adapted to Colorado’s climate.
Not messy or difficult to maintain
Your maintenance crew has enough on their plate with regular landscape maintenance. There’s no reason to increase their burden and your costs by having messy, difficult plants on your property.
Readily available from nurseries (not rare)
If you lose some of your landscape plants due to accidents, vandalism or bad weather, you will likely want to easily replace the missing vegetation. If the plant that needs to be replaced is hard to find, you might have to resort to replacing it with one that does not match.
Attractive/Interesting/Eye-catching
Attract eyeballs and attention to your business by choosing interesting trees, shrubs and flowering plants. Just as having aesthetically pleasing buildings or signage is good for business, eye-catching vegetation and other landscape elements makes good business sense. Choose Trees and shrubs with notable flowers or good fall color.
A Hawthorne tree in spring bloom.
In Summary
If you are planning a new commercial landscape or taking an assessment of your existing commercial landscape, keep these guidelines in mind. They’ll help you avoid potential problems that might repel clients and customers from your property, rather than inviting them in. An inviting landscape on your commercial property is one of the first steps to achieving business success.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
Attendees in the lobby of the Denver Botanic Gardens where the Tree Diversity Conference was held.
This past Spring, tree enthusiasts from around the region gathered at the Denver Botanic Gardens to listen and learn from various presenters on the theme of Tree Diversity for Colorado. It seems recent crises such as the discovery of Emerald Ash Borer infestation in Boulder has revealed the urgency for members of the Green Industry to seek out more hardy and appropriate tree species for our region. There are other reasons to seek out trees better adapted to our climate. As climate scientists continue to inform us, it is likely that Colorado’s climate will get warmer and drier, providing even more challenging growing conditions for trees. Also, biotic mixing will continue to increase as more people move goods and materials far and wide across the globe. That is the most probable scenario of how EAB was found in Boulder: it was brought there in a wooden crate shipped from Asia. What far-flung exotic pest will next appear in our area?
This year’s conference was the second occurrence of such a gathering in Denver. Several new tree species were presented to the audience, along with some old stand-bys, with a discussion of each tree’s merits.
Although there were several genera that are represented in the group of trees, the two genera with the most candidates are Maples and Oaks. The other genus with multiple species that should get wider consideration for planting in our area is Ulmus (elms). While most elms have been looked over because of Dutch Elm Disease and also the invasive nature of Siberian Elm (Ulmus pulmila), there are a few cultivars that we should consider planting in Denver.
Here are ten trees that were discussed at the conference (out of many others) that you might consider planting in Colorado and the surrounding region:
Large shrub or small tree with rounded form. The Manzano is a more tree like form of bigtooth maple. Once established, the bigtooth maples are drought tolerant.
Acer miyabei ‘Morton’ – State Street Maple Ht: 50’ Wd: 35’
Rough corky bark and leaf shape are similar to Hedge Maple, but its stronger growth rate and ascending branch habit result in a larger mature size. Excellent drought and cold tolerance. Very adaptable.
This maple provides red fall color, but unlike a red maple like Autumn Blaze (Acer x freemanii), the sugar maples are more adapted to the alkaline soils of Colorado’s Front Range urban corridor.
This large oak sports a massive trunk, deeply furrowed, that supports corky ridged twigs on spreading branches that makes for a broad and rounded canopy. This variety is more resistant to the galls that can affect other Bur Oaks.
Quercus muehlenbergii – Chinkapin Oak Ht: 40’ Wd: 40’
A durable and adaptable oak with narrow lustrous glossy dark green leaves and an open, irregular, rounded habit. Prefers well drained soil.
Quercus robur x alba ‘JFS-KW1QX’ – Streetspire Oak Ht: 45’ Wd: 14’
Dark green leaves of this narrowly columnar tree are mildew resistant. Turning red in autumn, they fall to reveal stiffly upright branches. Similar to Crimson Spire, but does not hold brown foliage through the winter
Ulmus davidiana – David Elm Ht: 40’ Wd: 30’
Medium sized tree, with vase shape. Resistant to Dutch elm disease.
Grown from seed collected in China, this sturdy, upright-growing elm was selected for superior performance on the hot, arid, windswept plains of western Oklahoma. Handsome, deeply corrugated leaves emerge coppery-bronze and mature to glossy green.
Ulmus japonica x wilsoniana ‘Morton’ – Accolade Elm Ht: 70’ Wd: 60’
Arching limbs and a graceful vase shape (similar to the American elm) characterize this hybrid elm selected and tested at Morton Arboretum. Glossy, dark green foliage changes to yellow in the fall and is resistant to elm leaf beetle feeding.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
As gardeners in Colorado may well know, our climate and altitude make for challenging growing conditions. This doesn’t mean we are completely immune from invasive exotic plants making an unwelcome home here. We do not have the burden that gardeners in wetter and warmer states may have at stopping the spread of invasive plants, but there are a few species you should be aware of so you can help stop these unwanted guests from gaining a foothold in our landscapes.
Why be concerned about invasive plants? They crowd out native plants, propagate uncontrollably, and may reduce forage for wildlife. Some may have a negative impact on your garden plants. And research suggests that some invasive species may pose dangers to humans through the increased risk of flooding due to damaged waterways, or increased fire danger.
The two worst invasive woody plants for Colorado and the surrounding region are the Russian Olive and the Tamarisk. Russian Olive (Elaeagnus angustifolia), is native to western and central Asia. It was introduced into North America in the latter part of the 1800’s. It is not related to true olive plants (Olea europaea) but its fruit is edible but not very palatable for human consumption. It out competes native plants because its seeds are irresistible to birds which spread the seeds far and wide. The seeds have a low mortality rate, germinate readily in poor soil (it can fix its own nitrogen in its roots), reach maturity quickly and thus outcompete native plants. In Colorado, they often begin setting a foothold in riparian areas, and then spread from there.
Russian Olives invading a wetland in New Mexico.
Tamarisk (Tamarix ramosissima), which is more of a shrub than a tree, similarly starts its spread in the riparian areas of the Colorado and other southwestern states. It has been such a successful invader of wet areas, that it has overtaken huge sections of the rivers of the southwest. However, it is not as tolerant of cold temperatures as is Russian Olive, which restricts its spread to the warmer, lower elevations of the southwest. Tamarisk is tolerant of many soil types, and thrives in full sun. One of the concerns about Tamarisk’s effect on native landscapes is how they out compete native vegetation, altering the nutrient cycles of riparian areas. They also consume large amounts of water, and secrete large amounts of salt, both items further slowing the success of nearby native plants. A massive amount of resources and manpower are being directed at the fight to stop the spread of this plant through the wildlands of the desert southwest.
…the Siberian Elm is “one of, if not the, world’s worst trees…a poor ornamental that does not deserve to be planted anywhere”.
Closer to Denver and the urban areas of Colorado’s front range, there are two trees that are common pests. These are the Siberian Elm (Ulmus pumila), and the Tree of Heaven (Ailanthus altissima). Both of these trees release a profuse amount of seeds, and these seeds are very adept at sprouting in disturbed areas. They proliferate along transportation corridors and abandoned lots. Both trees prefer full sun, but Ailanthus can tolerate some shade allowing it to invade some mature native forests.
Young Ailanthus altissima
Although not directly related, Ailanthus trees (a.k.a. Tree of Heaven) are often mistaken as sumacs. In springtime they produce many flowers that have a foul odor which some say is similar to cat urine. It rapidly out competes other tree species, releasing an allelopathic chemical which inhibits the growth of other plants. Some researchers have extracted this chemical from Ailanthus trees, successfully using it as an herbicide. Not only is this tree toxic to other plants, there have been anecdotal reports of it being slightly toxic to humans and livestock. Ailanthus trees can grow quite rapidly, leading to weak, unstable branches.
Siberian Elms also have structural problems, with many weak or dead branches that can break off in heavy wind. Siberian elms have a short dormancy period which leads to early flowering in spring, and late leaf drop in fall. In Colorado that means they can become dangerously loaded with wet snow in our common heavy spring snowstorms, or the occasional fall snowstorm, leading to heavy branches falling on roofs and vehicles. In addition to the dangers of breaking limbs, the trees do not have a very favorable appearance, with an awkward branching pattern. One doesn’t need to search too long before you find many Siberian elm seedlings sprouting up in unwanted spots in the urban landscape. The sprouts show up in shrub beds where they are difficult to remove by hand and hard to spray with herbicides without damaging neighboring desired plant materials. Siberian elms are susceptible to damage from elm leaf beetles which leave the leaves looking skeletonized, but it doesn’t seem to kill the trees. Notable horticulturalist Michael Dirr says the Siberian Elm is “one of, if not the, world’s worst trees…a poor ornamental that does not deserve to be planted anywhere”.
To be fair, I should mention that some people look favorably upon these four tree species, and say that in Colorado’s high desert climate (that is naturally and predominantly tree-less east of the Rocky Mountains), an invasive tree is better than no tree, especially in urban areas. I would beg to differ, noting that these trees are too difficult to control and remove, to the detriment of native flora and fauna. Please become aware of these invasive trees and be considerate about whether you want to allow these in your landscape.
This is the official blog of Outdoor Design Group, Colorado Landscape Architects. For more information about our business and our services, click here.
