There are many good reasons to plant natives in the home landscape. They are great choices to use in a more sustainable design, because if they are given conditions similar to their native “digs”, they will require little water, fertilizer and pest management. They also resonate with a local sense of place. Of course the word “native” often is used to mean a regional native and not just a Colorado native, but none-the-less, regional natives can also be used to create a more authentic western style garden or landscape.
Native plants also support native birds, butterflies and other insects and critters. And, of course, if they are cultivated well, they can be very beautiful. Sometimes people think natives are scraggly and unattractive because they have seen them in the wild under harsh conditions. For a native plant species that has gone through decades of Colorado’s extreme weather, survival is the ultimate criterion of success, not “lookin’ good”. And in fact, many natives have acquired mechanisms to shut down or decline in order to survive: some will drop leaves, go dormant, refuse to bloom, or die back. In doing so, they may look less beautiful to us humans, but they are conserving valuable resources. I have found that a little water and/or a little pruning at the right time is often enough to keep my natives looking beautiful.
One of my favorite natives in my xeriscape garden is Sand Sage or Artemisia filifolia. It is a Colorado native, growing on the dry eastern plains under 6000′ in loose and sandy soils. It is also called Threadleaf Sage since its leaves are very narrow, less than one millimeter wide. The color is very silvery and is especially beautiful when backlit, as with the late afternoon sun shining through it. The lower stems are woody, but as it matures each year, the new growth plus the narrow flower panicles and seeds wave wonderfully in a breeze, and therefore can make a silvery rhythmic complement to ornamental grasses.
The flowers are inconspicuous and can be cut off either before or after seed forms, to help keep the foliage denser. Sand Sage grows 3—4′ tall and 2—3′ wide, and can survive with no supplemental water, once established. I water one of mine five times a year and it is bigger and fuller then those getting no water. However it would be sure death to plant it in pure clay and to water it frequently. It would probably be fine to grow in clay if it were raised on a berm or hill, and seldom or never watered.
Artemisia filifolia often can get bare at the base, so growing something else, like penstemons, near it can make it more attractive while providing a dramatic silver foil for blue, red or yellow flowers. By spring, if the shrub hasn’t been cut back earlier, prune off the upper parts by 6″ or even by a third. This helps develop a denser and more attractive plant. If you are looking up Sand Sage in Weber’s Colorado Flora, look under Oligosporus filifolius.
Though not a Colorado native, Fernbush is a regional native growing in Utah, Idaho, Nevada, Wyoming and Arizona, often in rocky soils. Its leaves do look amazingly fern-like and, thankfully, it is easier to say “fernbush” than Chamaebatiaria millefolium, its scientific name. It is a woody shrub growing to 4′ high and often wider than tall. The leaves are aromatic, giving this native a second common name, Desert Sweet, and the leaves are nearly evergreen. It is a member of the rose family, having small 5-petaled white flowers in clusters, resembling a spirea. These flowers can nearly cover the foliage in summer and a lighter bloom may occur in the fall. The blossoms attract wasps of every kind and color, which are so intent on the sweet nectar that they barely notice a gardener weeding at its base. Far from being a magnet for pests, the attraction of Desert Sweet to wasps brings an army of beneficial insects to the garden that will eat aphids, caterpillars, leaf-hoppers, ash sawfly and beetles. Some of these wasps are microscopic, like the Trichogramma wasp that lays its eggs in the eggs of the Codling Moth which is our most common “worm in the apple”.
Fernbush is very heat and drought tolerant and should be grown with good drainage and little water. Like Sand Sage, it can be planted in clay on a hill or berm if it is seldom, if ever, watered. It is rumored that Fernbush will be chosen for the Plant Select program in 2006.
Ptelea trifoliata (pronounced TEA-lee-uh) is also known as Wafer Ash or Hop Tree. It is native to Colorado south of Colorado Springs from 5000—9000′, and along rocky stream banks, canyons and ravines in Oklahoma, Texas, Arizona and New Mexico. It is a small tree 10—15′ tall and wide, often multi-trunked. The leaves are ash-like, shiny and deep green with leaflets grouped in threes (trifoliate). These leaves are glandular, have a pungent, hop-like smell if crushed, and turn a beautiful yellow in the fall. The effect of the rich yellow blanket of leaves under the bare tree can be stunning.
The small flowers are greenish-white in 2″ clusters and bloom in June with a pleasant vanilla fragrance that becomes stronger as the tree gets bigger and bears more flowers. These flowers are not very showy, but the circular winged seeds (wafers) that follow in late summer are conspicuous. These flat fruits have been used as a hops substitute. Whereas Ptelea can be grown very dry, it stays more shrub-like in stature. Hop Tree does well in full sun and, reportedly, in shade.
Arctostaphylos x coloradoensis ‘Mock Bearberry’ is a broadleaf evergreen shrub that is related to the more familiar Kinnikinnick. It was originally found and selected by Betsy Baldwin who believes it may be a natural hybrid between Kinnikinnick (Bearberry) and Arctostaphylos nevadensis. The name “Arctostaphylos” comes from the Greek words “arktos”, bear and “staphyle”, grape. The common name “Manzanita” means “little apple” which refers to the little red fruits. This is a native of Colorado and similar forms exist throughout the west. It is a very distinctive shrub with leathery, oval, rich green leaves and beautiful smooth, reddish brown stems. In Colorado, Manzanita is usually found at higher elevations where there is more moisture and less heat. And although it is xeric, once established, and can tolerate full sun, it may be more easily grown in part shade or on an eastern exposure with a little supplemental water. Under xeric conditions, it may only get 8—15″ high and 3—4′ wide, but with good soil and moderate water, it can reach 3′ high and 5—6′ wide. Panayoti Kelaidis, world famous plant explorer and director of Denver Botanic Garden Outreach, once remarked that he thought Arctostaphylos could replace Juniper as the most popular evergreen foundation planting in Colorado.
In very early spring, tiny, urn-shaped flowers appear that are white or pink. And then in September, the bearberries form which are small, dry, red berries. ‘Mock Bearberry’ was named a Plant Select winner for 2005. Although Betsy Baldwin had collected many forms of Manzanita, ‘Mock Bearberry’ clearly stood out as one of the most beautiful, robust and garden-worthy varieties. ‘Panchito’ is another similar variety that will be Plant Select in 2006.
We are very fortunate to live in a time when these natives are available. Not long ago, I remember, none of these plants were available in the normal trade. They were only to be found in the “Pets” collections of a few idealistic and visionary propagators. So take this opportunity to get them while you can and to encourage those nurseries that have often gone to a lot of trouble to figure out how to grow them from seed or cuttings. Natives have become popular for good reasons. Plant at least one of these four and see for yourself.