Blackwelder: Plants need care in heat

Published 12:00 am Thursday, June 2, 2011

Last week Rowan County experienced near record low temperatures ó this week possible record highs. Plants will suffer with the rollercoaster weather. Irrigation during this type of weather is critical for survival of plant materials, especially those that have just been planted.
Below are a few tips that may help plant materials survive the extreme heat.
Irrigate plants early in the morning. Applying water in the heat of the day may cool off plants, but it also wastes water through rapid evaporation. Irrigating late in the evening encourages fungal diseases. Irrigation with drip systems is excellent for newly planted trees and shrubs and vegetable gardens. This type of system meters water near the plantís root system without waste.
Do the plants really need water or are they just hot? Some plants such as hydrangea, rhododendron, impatiens or ornamental sweet potato wilt in the heat of the day, but have adequate moisture to survive. Wilted plants should be checked the next morning; if they are still wilted, irrigate them thoroughly. Over-watering kills plants much quicker than lack of water.
Mulch plants. Mulching holds moisture and cools the soil. Three to four inches of bark, pine needles, compost or other types of organic mulch reduces water consumption.
Some plants need to be irrigated often. Plants in pots, especially clay pots or hanging baskets, lose moisture quickly. These containers may need water every day and more often, twice a day during periods of extreme heat and drought.
Keep a constant check on plants. People who go on weekend vacations often come home to face dead or heavily damaged plants during excessively hot, dry weather. Itís important to arrange for a neighbor or friend to water plants, especially newly planted trees or shrubs if youíre out of town for a few days. Now is the time to strongly consider timers to water during your absence.
Some plants do poorly in hot weather and there is nothing you can do to alleviate the problem. Fescue turns brown and goes dormant; leaf drop occurs on some broadleaf shade trees, other plants may turn pale green and die outright. Unfortunately, temperature extremes seem to be a common occurrence over the past few years. Extreme stress often takes its toll on both trees and shrubs.
Darrell Blackwelder is the County Extension Director with horticulture responsibilities with the North Carolina Cooperative Extension Service in Rowan County. Learn more about Cooperative Extension events and activities by calling 704-216-8970 or online at