Drought tolerant trees and shrubs were profiled in last month’s column, but groundcovers, perennials and grasses are needed to round out the palette of plants needed to create a diverse and interesting garden. Plants that survive well with low water requirements can bring color, shape and diversity to a landscape even in the hottest weather.
A tough groundcover that grows in full sun to part shade is the hardy Plumbago, ceratostigma plumbaginoides. I put a few small plants in a back border years ago and still enjoy the continuous variety this selection offers. It is truly special with brilliant blue flowers that attract butterflies before the foliage turns to deep red in the fall. Another plus is that it slowly spreads by underground runners despite competition from tree roots.
After a Miscanthus grass threatened to take over my garden and needed to be forcefully removed, I vowed I would never put another grass into my borders.
Thankfully, never is a long time and I have reconsidered after researching drought tolerant plants. There is one small, 18-inches tall, grass that I will be looking to add next spring. Autumn Embers Muhly grass, muhlenbergia reverchonii, is not just drought resistant in hot, sunny summers but offers stunning red flowers in autumn with reddish brown blades in the winter. This native has fine-textured gray green foliage in weeping mounds during the spring and summer seasons. Be sure to purchase the correct variety as there are many grasses to chose from and not all will be drought tolerant and also look wonderful.
There are a number of perennials that will withstand summers with little water. Here are a few to consider adding to your landscape, especially if much of your garden has a sunny exposure.
Sunset Hyssop, or agastache tuberosa, is a southwestern native perennial. Soft gray-green leaves have a licorice fragrance. Tubular soft orange flowers on two-foot tall stems will attract moths and hummingbirds for your endless enjoyment.
Liatris aspera, a three or four-foot tall Gayfeather, is heat and humidity tolerant. Grow it in full sun to see lovely spikes of tiny pink flowers drawing in butterflies and hummingbirds to the sweet nectar. The foliage is narrow producing a swaying, feathery deep dark green appearance. Also, Liatris spicata Kobold, an east coast native, does very well in my garden in full sun.
Butterfly weed, asclepias tuberosa, is another native perennial with clusters of orange, yellow or red flowers attracting butterflies and bees. Monarch and Queen butterfly caterpillars feed on this variety. It thrives in full sun but beware that it will self-sow if you do not deadhead the flowers or remove the seed heads.
A native species with thick roots that will seek and retain water is the prairie Coneflower, echinacea augustifolia. The rose-purple daisy like flowers will attract finches, butterflies and bees throughout the seasons when grown in full sun.
Wild indigo, baptisia minor, is a native that can be grown in full sun because it has a long tap root that goes deep in the soil to obtain water. The lavender-blue flower spikes attract bees and supplies food for the caterpillars of blue, sulphur and indigo butterflies.
Another native herbaceous perennial that prefers dry, sunny conditions is euphorbia corollata, which tolerates all types of soils. This plant attracts butterflies and other pollinators but is rabbit and deer resistant. It is often used as a groundcover in areas of the garden where others plants will not survive. It can grow to two-feet with single, white flowers. Warning: the foliage of this plant contains a white latex that can be irritating to the skin.
All of the trees, shrubs, grasses, groundcovers and perennials discussed in these two columns will also thrive under normal water conditions. The difference being that when and if the weather becomes unusually dry, hot or humid these plant varieties will still perform reasonably well and provide us with color and beauty in our landscapes while supplying food for our pollinators.
Josephine Borut is currently on the board of directors of the Long Island Horticultural Society and is a past board member of the Long Island Rose Society. She is a current member of the American Horticultural Society, American Rose Society and Herb Society of America. The Long Island Horticultural Society will meet on Sunday afternoon in the Hay Barn at Planting Fields Arboretum in Oyster Bay. Programs begin at 1 p.m. The next meeting is April 23 and the speaker is Dr. Michael J. Balick, vice president for Botanical Science at the New York Botanic Garden. His topic will be 21st Century Herbs. For more information, go to www.lihort.org.