Soak plants to save them in triple-digit heat
It looks like the tripledigit summer weather has arrived and although one day is tough, multiple days in a row have a cumulative stressful impact on our plants.
The temperatures along with intense sunlight and dry, blowing winds, without rain, results in a solar furnace where plant growth is secondary and survival is the primary goal. You can help your plants battle the heat and survive the furnace effect by watering, better yet soaking, your plants.
Mulching the top of your soil with a 2- or 3-inch layer of bark mulch, pine straw, cottonseed hulls, cocoa hulls or other mulch will cut down on surface water evaporation and will reduce watering needs by about half. Mulches will also keep the soil and your plant roots cooler and happier in hot weather and will dramatically reduce weed pressure in your garden beds or decorative containers.
Some plants thrive in the heat and put on their best flower show over the next few weeks. These include flowering shrubs like crapemyrtle with their tremendous flower heads in white, many tones of pink, red and lavender.
We don't have an official state flowering shrub, but if we did, it should be the crapemyrtle. They are available in dozens of varieties from dwarfs that only grow a couple of feet tall to small trees that grow to 20 feet or slightly taller. A lot of the older varieties would freeze back to the ground every year or every few years.
Better breeding and plant selection have not only led to move intense colors, longer lasting and more flowers but also to varieties that are more freeze tolerant and less likely to freeze back each year. One of the top crapemyrtle breeders in the country is Dr. Carl Whitcomb, former Oklahoma State University horticulture professor who has been breeding for many years at Lacebark Inc. outside of Stillwater. Dr Whitcomb has patented over a dozen crapemyrtles including the popular Dynamite Red crapemyrtle. If you don't have crapemyrtle in your yard or on your property, you may want to add some for bold summer color.
Vitex, also known as chaste tree or butterfly bush, produces great quantities of blue flower spikes and loves the Oklahoma heat. The bees and butterflies love to visit and pollinate this Mediterranean flowering shrub that can grow into a small tree with age and good conditions. Althea, or Rose of Sharon, hardy hibiscus and the many varieties of hydrangeas are other flowering shrubs that do well in the summer heat and produce an impressive array of color as long as you satisfy their water needs.
Many flowering annuals thrive in the summer heat including periwinkle, sweet potato vine, zinnia, marigold, penta and fibrous begonias. Many perennials are at their best in the summer heat including Shasta daisies, gloriosa daisy and other Rudebekia and Gaillardia varieties that bloom boldly. Even bulb crops have summer stars including gladiolus with their colorful and tall flower spikes to dahlias blooming now and caladiums with their impressive and colorful foliage that stands out in your shade gardens.
You can still plant these annuals, perennials and flowering shrubs, even in the intense summer heat, as long as you are committed to water these new plantings and keep a watchful eye on them as they get established. After watering, two of the best secrets of success in Oklahoma gardening are good soil preparation before you plant and mulching after you plant.
The triple-digit temperatures also bring our most intense insect pressure of the year. Be observant and be prepared to act to control bagworms on your junipers or needle evergreens, webworms on pecan, walnut and other trees, red spider mites, aphids, mealy bugs or thrips on your heatstressed plants. Visit with your local nurseryman or county extension office to ID any problems and to plan a course of action.
Enjoy and marvel at your garden and plants as you battle the heat and make certain you stay alert to water needs and care for your garden through this stretch of summer sauna weather.