why do plants wilt on a hot summer day

Wherever possible, improve soil conditions before you plant. Adding organic material for nutrition and sand, peat moss and other drainage amendments gives your plants the best opportunity to send down strong, abundant roots, equipping the plants to survive stress of all kinds. Factor wilting into your garden plan, if you can. For example, all kinds of hydrangeas (Hydrangea spp. ), varieties of which are grow in U. S. Department of Agriculture plant hardiness zones 3 through 9, are well known for wilting. Plant them where they get morning sun but get some afternoon shade. Keep an eye on annuals with broad leaf surfaces, like cucumbers (Cucumis sativas), and use their drooping leaves as an early-warning watering reminder.

Watering techniques can decrease wilt. Deep-watering several times a week, rather than brief, daily watering, provides enough for growing plant roots in hot weather. Aim water at the roots when you water, and water the soil beyond the visible spread of branches. A thick layer of mulch keeps plant roots cooler and helps prevent water evaporating from the soil. Give wilted plants time to recover before declaring them dead -- wilting signals distress but also serves as a way for plants to survive it.
Plants mainly wilt during high temperatures because their transpiration rate exceeds the rate at which they can absorb water, says Virginia Tech horticulture professor Bonnie Appleton.

Plant leaves have oodles and oodles of tiny holes call stomata, or pores, which allow vapor to escape. A plant regulates the rate of transpiration according to its water requirements and the weather. "If they wilt during the day, but recover at night, then there is adequate soil moisture," says Appleton. If plants don't recover at night when temperatures cool down and when their transpiration rate drops, then the soil has run out of available water and irrigation is needed. Hydrangea likes to wilt during the day, then often recover at night, something I witness often in my own garden. Cucumber and squash also exhibit this behavior. But, if the weather is temperate, the soil moist and the rains regular -- and you still have wilting leaves, you may have root rot, according to York extension agent Jim Orband. "With root rot, the plant is not able to take water up, therefore you get wilting," he says.

Whenever you water your plants, take the time to soak them thoroughly, using soaker hoses, if you can. Trees that are less than two years old need careful attention because they are still developing root systems; established trees can get through mild droughts without supplemental water. And, when you design flower beds and plantings for trees and shrubs, group them according to their water needs -- don't put plants that like it dry in the same area as plants that like it moist.

Also, you lawn should be watered separately from your flowers and shrubs because grass needs far more moisture than ornamentals do. For an excellent article on how to effectively water, visit North Carolina extension at www. bae. ncsu. edu/programs/extension/publicat/wqwm/ag508_6. html. If you don't have a computer and want a copy of this article, send me a note requesting it and a stamped, self-addressed envelope to Kathy Van Mullekom, Daily Press, 7505 Warwick Blvd. , Newport News, 23607. JUDGE THE BASKETS. You'll find some good ideas for combining plant textures and colors in the 10 flower baskets on display at Riverwalk Landing along the waterfront at Yorktown. You can also help judge those baskets for a floral design competition sponsored by the York County Economic Development Authority and the Riverwalk Landing Business Association.

Participants in the contest include Walter Reed, Gloucester and Mathews garden clubs; Willow's Fine Flowers and Gifts; Claire Murray store; Nikki Cooper and Jack and Nancy Kane (with plants provided by Charlie's Produce and Nursery in York County); The Southern Yankee, York master gardener Claire Britcher and Anderson's Home and Garden Showplace. Prizes for best design will be awarded on Labor Day, so hurry and cast your ballot in a voting box at the Claire Murray store at Riverwalk. For details, contact Sherry Rougeau at 877-3353.