High Elevation Gardening Web Log "Blog"

Perennial refers to herbaceous perennial plants that grow and flower for two or more years. Though not as long blooming as annuals, perennials provide showy, colorful displays. To obtain several seasons of color, group plants together that have similar bloom times so that when one group starts to fade, a nearby group will come into flower. The following are a selection of easy-to-grow perennials that bring on three main waves of color for late spring, summer and early fall.

My favorite low-water perennial is long-blooming ‘Moonshine’ yarrow (Achillea x ‘Moonshine’), said to be one of the best garden perennials ever. With regular dead-heading, lemon-yellow flower clusters appear June through September. Unlike the some rampant varieties of yarrow, ‘Moonshine yarrow is non-invasive. Contrast ‘Moonshine’ yarrow with a blue spring bloomer such as ‘Walker’s Low’ catmint (Nepeta x ‘Walker’s Low’) or perennial salvia ‘Blue Hill’ (Salvia x sylvestris ‘Blue Hill’).

For a more robust display, consider larger ‘Coronation Gold’ yarrow paired with sizable ‘Six Hills Giant’ catmint described by High Country Gardens as a catmint on steroids. To brighten the look, add long-blooming red valerian (Centranthus ruber), an old-fashioned cut flower with dense rosy-red floret clusters. Red valerian is invasive on the west coast of the United States but our drier climate keeps it in check.

For summer color, start with pineleaf penstemon (Penstemon pinifolius), a southwest native that sports tubular orange flowers for many weeks. Color variations include ‘Mersea Yellow’, a pineleaf penstemon discovered in an English garden in 1980 and ‘Nearly Red’, a red form recently developed by High Country Gardens.

Contrast the tube-shaped flowers of pineleaf penstemon with either tickseed coreopsis (Coreopsis grandiflora) or any of the gaillardia cultivars (Gaillardia x grandiflora). Both are members of the aster family and have abundant ray petals. Coreopsis has large golden-yellow flowers while gaillardia has orange to red petals tipped with yellow.

Another summer vignette joins bright orange butterfly weed (Aslepias tuberosa), sunny yellow Missouri evening primrose (Oenothera macrocarpa) and wine red poppy mallow (Callirhoe involucrata), a combination introduced by High Country Gardens and inspired by the short-grass prairie. Lots of sun is a must and plants do best in a well-drained soil.

An excellent choice for late summer to early fall color is Agastache, a genus of nectar-rich tubular flowers. Many are native to the southwest and are frequented by hummingbirds. Texas hummingbird mint (Agastache cana) has raspberry-pink flowers and blooms summer to fall. Licorice mint hyssop (Agastache rupestris) has a spicy fragrance sometimes described as rich, root beer and pinkish orange flowers. Many hybrids are available such as ‘Desert Sunrise’, ‘Apricot Sunrise’ and ‘Tutti Frutti’ to name a few.

Combine agastache with gayfeather (Liatris punctata), a prairie native with deep purple flower spires. For contrast, select any of the ornamental goldenrod cultivars (Solidago sp.) Contrary to popular belief, goldenrod seldom cause fall allergy problems as its pollen is too heavy and sticky to be blown around. The culprit is likely ragweed.

All of the perennials mentioned thrive in full sun with low water though some can handle light shade. To keep your garden looking great when plants have finished flowering, trim off the fading flowers. As with all new plantings, water regularly until plants are well-established. Then hold off on the water and enjoy many months of color and a much lower water bill.

High Country Gardens (www.highcountrygardens) has images and descriptions of many of these plants.

By Hattie Braun
The author is a Master Gardener program coordinator for Coconino County Cooperative Extension. For more information about the Master Gardener Program, call 774-1868 ext. 17 or visit our Web site: highelevationgardening.arizona.edu.