Learning from the Drought
by Diane Relf

If you have considered designing your flowerbeds to minimize the use of water, this has been the perfect year to select the plants that will do best in your area. Look at those plants in locations that never received water and write down what survived. These will be the most tolerant of drought and thus good plants to consider for a landscape with minimum water needs.

It is easy for me to make these determinations in my yard, as my only water source is a spring that is not strong enough to support general landscape watering. Though I water some container plants on my deck, I rely exclusively on rain to provide moisture for the landscape.

Note Each Different Plants' Reactions

Among my native plants, the goldenrod blossoms faded almost as rapidly as they opened but the plants themselves will be back again next year for a longer show. The boltonia on the other hand presented a long display of white clouds -- unfortunately the only "clouds" that we saw for a long time. The Joe-pye-weed was shorten in that it bloomed but survived. Much to my surprise my Blue Cardinal Flower (Lobelia siphilitica) gave a reasonable number of flowers. Of course, it only grows in the over-flow bed of the spring box and on a short-season spring near the garden. Both of these locations were very low on water this year, but apparently the reduced level was not as damaging as I expected. Other plants that rely on this same supply of water, such as Pulmonaria 'Mrs. Moon' and hardy begonias were both seriously stressed but did survive.

Among the most impressive plants in my flowerbeds was the perennial ageratum. It gave a long period of clear blue flowers, which contrasted well with the yellow tansy blossoms. The purple Verbena 'Homestead' stood up to complete neglect and kept on growing. All three cultivars of Gaura (a plant that I remember as a wild flower from my childhood in Texas) flowered well and still displayed their butterfly like blooms in mid-October.

Select the Most Impressive and Strongest For Landscape

The Gloriosa daisy (Rudbeckia hirta) gave a nice summer show; but I was surprised at the short duration of the flowers on the perennial Black-Eyed Susan (Rudbeckia fulgida).

Among the self-seeding annuals the nicotiana was probably the standout; however, the cleome and laventera did produce some nice flowers. In a bed that I prepared and planted while we were still getting a bit of rain, the cleome and laventera that I started in the greenhouse did much better.

Cleome reached 6 feet and bloomed up to mid-October, while the laventera made it to the end of August. The marigolds managed to sustain their color to mid-October. Impatiens and coleus in a shady location appeared to hit permanent wilt by early September. They were such a sad sight that my husband relented and watered them a couple of times, but the ratio of available water to need meant that they were doomed. But then a miracle happened, we got about 2 inches of rain and they revived and were providing some show in mid-October.

I am highly impressed with the perennial coreopsis. I started them from seed indoors and set the plants out in late spring. They did not reach blooming size this year, but they grew vigorously and retained a good green color. I am looking forward to excellent performance from them next year.

Secret To Success Is Organic Matter in Soil

Certainly there are other plants to choose, but at least there is comfort in knowing that you can have a flower garden without over-burdening your water supply. The main secret to my success has been enormous amounts of organic material supplied continuously to the soil, both as an amendment and as a mulch. Never stop adding the leaves, woodchips, grass clippings (herbicide free only), and other material if you want to reduce the amount and number of water applications.

Dr. Diane Relf is an environmental horticulturist with Virginia Cooperative Extension and a member of the faculty of Virginia Tech.

October 22, 1998 The Virginia Gardener
Visit Virginia Cooperative Extension