Extension News

Ask the ISU Extension Garden Experts: Drought-Tolerant Annuals and Vegetables for Shady Sites

Note to media editors: Got gardening questions? Call the Hortline at (515) 294-3108, Monday-Friday from 10 a.m. to noon and 1 to 4:30 p.m., or e-mail us at hortline@iastate.edu. For more gardening information, visit us at Yard and Garden Online, http://www.yardandgarden.extension.iastate.edu.


Which annuals are drought tolerant?

For best performance, most annuals require consistent moisture throughout the growing season. However, some annuals are quite drought tolerant. Drought tolerant annuals include periwinkle (Catharanthus roseus), cockscomb (Celosia spp.), spider flower (Cleome hassleriana), cosmos (Cosmos spp.), dahlberg daisy (Thymophylla tenuiloba), globe amaranth (Gomphrena globosa), medallion flower (Melampodium paludosum), moss rose (Portulaca grandiflora), mealycup sage (Salvia farinacea), creeping zinnia (Sanvitalia procumbens), dusty miller (Senecio cineraria), marigold (Tagetes spp.), and zinnia (Zinnia spp.).

While the aforementioned annuals possess excellent drought tolerance, they may need to be watered a few times until the plants develop a good root system. However, once established, they require little watering during the remainder of the growing season.

Which vegetables will grow in partial shade?

Most vegetables require at least six hours of direct sun each day to produce a good crop. Leafy vegetables, such as leaf lettuce, spinach, collards, Swiss chard and kale, can be successfully grown in areas that receive three to four hours of sun. Other possibilities for partial shade include radishes, kohlrabi, beets, cabbage, cauliflower and broccoli.

When should I prune my weigela?

Weigelas bloom on both old and new wood. Plants bloom heavily in late May or June on the previous year’s growth. They also bloom intermittently through the summer on the current season’s growth.

Weigelas are prone to winter dieback. Carefully examine plants in late winter/early spring and prune out any dead wood. If the weigelas suffer little dieback, remove a few of the largest, oldest stems on large, well-established plants. Removal of a few large branches in late winter/early spring allows the shrub to bloom in late spring and produce vigorous new flowering shoots for future years. Weigelas also can be lightly pruned immediately after the late spring bloom.


Contacts :

Richard Jauron, Horticulture, (515) 294-1871, rjauron@iastate.edu 

Del Marks, Extension Communications and External Relations, (515) 294-9807, delmarks@iastate.edu