A Front Range planting palette
Natives and Plant Select introductions that fit Front Range sun, clay, and hail, with origins labeled so a trial plant is not called a native.
The Front Range, from about Fort Collins through Colorado Springs and the Denver metro, is a high-plains climate pushed against the mountains. Summers are hot and bright, winters swing, hail is a season rather than a rumor, and soils are often clay and alkaline.
The plants that work here are the ones that tolerate that list after they have been watered through their first summers. This page separates regional natives from plants that have been trialed here and are not native.
Plant Select is the trial program of Denver Botanic Gardens and Colorado State University. A Plant Select introduction has survived regional evaluation. That is a strong recommendation and a different fact from “it grew here before settlement.”
Water and soil come first. Read xeriscaping and alkaline soil before you turn this list into a receipt. Every plant below is drought-tolerant only once rooted. The first one or two summers are irrigation summers.
Grasses that can replace lawn and also live in a border
Blue grama (Bouteloua gracilis) is a plains native and Colorado’s state grass. In full sun it is a fine lawn, a meadow, or a front-of-border tuft. It will tan in drought. That is the species, not a failure.
Buffalo grass (Bouteloua dactyloides) is the spreading lawn grass for full sun, covered in water-wise lawns. Little bluestem (Schizachyrium scoparium) is the taller native grass for a border, with color in fall and a crown that sits low enough to survive hail better than a tall, brittle shrub.
Do not plant these three in shade. Do not mow little bluestem as if it were bluegrass.
Perennials with a local record
Rocky Mountain penstemon (Penstemon strictus) is a regional native, blue-purple, and one of the more forgiving penstemons in an ordinary bed if drainage is decent. Scarlet bugler types (Penstemon barbatus) pull hummingbirds and want the same drainage. The hybrid line sold as Penstemon × mexicali, including ‘Red Rocks’ and ‘Pikes Peak Purple’, is a Plant Select class of garden hybrids, not a wild species. They are useful, long-blooming, and honest only if you do not call them natives.
Blanketflower (Gaillardia aristata) is a plains and foothill native that reblooms if you keep it from exhausting itself, and it handles heat. Chocolate flower (Berlandiera lyrata) is native farther south and widely grown along the Front Range for the morning scent. It is a garden plant with a Southwestern range, not a Denver endemic.
Winecups (Callirhoe involucrata) are a plains native that Plant Select has promoted, a low trailer for a hot edge. Desert four o’clock (Mirabilis multiflora) is a native mound that dies back and returns, too large for a tiny strip and excellent where it has room.
Sunset hyssop (Agastache rupestris) is a Southwestern native used heavily in Front Range pollinator beds. It wants drainage and dies in a wet clay hole. Fringed sage (Artemisia frigida) is a native silver foliage plant for the hottest, driest spot. It is a better choice than spreading an aggressive artemisia you cannot pull.
Shrubs that belong, and two that are merely successful
Rubber rabbitbrush (Ericameria nauseosa) is a native shrub of the high plains, gold in late summer when almost nothing else is feeding bees, and it seeds around. Give it a rough spot, not a formal foundation. Apache plume (Fallugia paradoxa) is native in southern Colorado and the Southwest.
It handles heat, bloom, and a fluffy seed head, and it is more at home in the southern Front Range and northern New Mexico than in a cold Palmer Divide hollow. Both resprout after hail better than a lilac that has been sheared into a ball.
Red yucca (Hesperaloe parviflora) is a Plant Select staple and a Chihuahuan Desert plant, not a Colorado native. In a gravelly, well-drained bed along the Front Range it is a tough hummingbird plant.
In a soggy clay lawn it rots. Ice plant cultivars (Delosperma), including several Plant Select selections, are South African. They want sharp drainage and a dry winter crown.
They are legitimate Front Range rock-garden plants and a poor choice for a mountain snowbed or a sprinkler zone. Say what they are.
A small sunny border that can take hail
A bed in full sun, mulched with chips or fine gravel depending on the plant, might run: blue grama and little bluestem for structure, Penstemon strictus and blanketflower for early and midsummer, chocolate flower and sunset hyssop for the long middle, rabbitbrush for September.
Add winecups at the hot edge. Leave the crowns in place over winter and cut them back in spring, so a January wind is not hitting bare soil and a bare crown. Hail will shred the August flowers.
The grasses and the penstemon crowns come back. That recovery is the design. A border made of one-time annuals has to be replanted after the storm. A border made of these perennials looks rough for two weeks and then continues.
Pollinators get a season if you keep that sequence. Early penstemon, midsummer blanketflower and hyssop, late rabbitbrush.
Showy milkweed (Asclepias speciosa) is the native milkweed for monarchs. It spreads. Put it where a runner is a gift, not in a two-foot formal edge.
Avoid insecticides on plants that are in bloom. A pollinator border sprayed for aphids on contact is no longer a pollinator border.
What to leave at the nursery
Skip the plant that needs constant water and acid soil: blue hydrangea as a foundation hedge, azalea, a blueberry hedge, pin oak.
Skip a “drought-tolerant” label on a plant sitting in a greenhouse saucer if you have no local record and no extension note. Russian sage is tough and widely planted and not native, and in some soils it runs.
If you plant it, plant it where running is acceptable. Myrtle spurge is a worse problem. It is invasive in Front Range open spaces. Do not plant it, and pull it if you inherited it, carefully, because the sap irritates skin.
Trees are a separate budget and a separate set of failures. Use the tree page rather than a maple because the nursery has a sale.
Checklist
- Call a plant native only if its range includes this region. Call Plant Select plants trialed.
- Water for one or two summers. Then test the “drought” claim.
- Put ice plant and red yucca in sharp drainage, and do not call them natives.
- Use blue grama and little bluestem in sun, not under a north eave.
- Plan for hail by choosing plants that resprout from the crown.
- Keep a sequence of bloom if you want pollinators past June.
- Do not plant myrtle spurge.
- Match the irrigation valve to the bed. One lawn zone will ruin this list.
The month-to-month outdoor work sits on the Front Range calendar. The same plants will not all transfer to Logan or to Taos. Those palettes are their own pages.
Sources
- Plant Select, Denver Botanic Gardens and Colorado State University.
- Denver Botanic Gardens, for regional horticulture and the Plant Select partnership.
- CSU Extension, Iron Chlorosis of Woody Plants.
- Denver Water xeriscape principles, for the water framework around any of these plantings.
- Colorado state grass designation for blue grama.