By Martha Kirk, Colorado Master Gardener
Is your garden facing the late summer doldrums? Need color to extend the season? Try these perennials to zhuzh up the garden with diversity, texture and color.
Typically, allium is known as a spring-blooming bulb, but Allium millenium is a bulbous perennial that blooms in late summer. It is a cross between Allium nutans and A. lusitanicum and was named Perennial Plant of the Year in 2018. It likes well-drained soil, a sunny location and grows about 12” tall. This compact, handsome plant attracts bees and butterflies, and is rabbit and deer resistant.
Left, Allium millenium, Photo: Martha Kirk. Right, Liatris ‘Kobold’, Photo: broadwayroadnurseries.com.
Liatris is one of those must-have plants. They do not disappoint, whether native or hybridized. In native gardens, the drought tolerant Liatris punctata, looks right at home blooming alongside native rabbitbrush. The hybrid Liatris spicata ‘Kobold’ puts on a lovely late summer display. It tolerates all soils including clay, and adds vertical height where needed. Plant it with yellow daylilies that bloom at the same time for an attractive combination.
Echinacea is a garden staple with its long bloom times and assorted colors and heights. Try Echinacea paradoxa for prairie style gardens, or the hybrid Echinacea x ‘Cheyenne Spirit’ that blooms multiple colors in one plant. Echinacea is not picky about soil and attracts bees and butterflies. Plant it in full sun or part shade.
Left, Echinacea paradoxa, Photo: Martha Kirk. Middle, Echinacea purpurea, Photo: Martha Kirk. Right, Echinacea ‘Cheyenne Spirit’, Photo: All American Selections.
Physostegia virginiana (obedient plant) blooms on either white or pink spikes. It provides color into the fall season and attracts hummingbirds. Native to North America, obedient plant is adaptable to many growing conditions. It requires average soil and water, full sun or part shade, and it is easy to grow with minimal care.
The genus Penstemon is quite large, so to narrow it down, consider the Mexicali series of penstemons for continuous blooms June-September. Penstemon x mexicali ‘Pikes Peak Purple’ and ‘Red Rocks’ are two popular choices from Plant Select® to include in a sunny garden. They are easy to grow and perform well, and simple deadheading encourages new blooms for visiting hummingbirds and bees.
Left, Physostegia virginiana, Photo: pinterest.com. Middle, Penstemon ‘Red Rocks’, Photo: Plant Select. Right, Agastache cana, Photo: Plant Select.
Nothing says late summer like Agastache. Its blooms attract bees, hummingbirds and butterflies to the garden. Agastache often has fragrant foliage (bonus!); Agastache rupestris smells like licorice while Agastache cana smells like bubble gum. Flower colors range from blue, red and orange, to dark pink. Agastache needs full sun and well-drained soils. Avoid overwatering and cut them back in the spring to help with winter hardiness.