We are now in the heart of Oklahoma summer weather which means bright sunshine, long days and often intense heat. From now through the end of August the most important job for Oklahoma gardeners is making sure your flowers, vegetables, trees, shrubs and lawn get adequate water. The deeper rooted your plants are the less often they will need supplemental watering as they will access to more soil moisture. Annuals and shallow rooted plants will need your watering help more often, even daily or every other day if grown in containers, hanging baskets or open well drained soils. Learn to read your plants to know how often to water based on heat, wind and soil conditions. Softer, tender plants will wilt or turn limp from drought stress. Most all plants, even deeply rooted and trees will turn a lighter shade of green, even slightly grayish or bleached out when really dry and pleading water. It is best to soak good when you do water so the moisture will soak 6” or more into the earth rather than just squirting or spraying the foliage of your plantings.
There are some plants that absolutely love the heat, the hotter the better, as long as they get sufficient rain or water to support their growth. Sweet Potato vine can grow several inches per day when we are at triple digit temperatures. Periwinkle, penta and copper leaf plants all grow and flower best when the heat seems the most challenging. One of the prettiest flowering shrubs we enjoy in Oklahoma is Crape Myrtles and they bloom and do best over the next few weeks when the heat can seem intense. Somebody needs to start a Crape Myrtle Festival or make Crape Myrtle our state flowering shrub since they add so much color to our Oklahoma summers. There are many wonderful varieties available with flower tones of pink, red, lavender and white. There are dwarf varieties that only grow 2’ or 3’ tall, varieties that make small trees of fifteen to twenty-five feet tall and many selections that fall in between at six to fifteen feet tall. Crape Myrtles suffer very few insect problems but they can suffer from powdery mildew when we get damp or high humidity conditions. Mildew can be controlled fairly easily with a good fungicide. Some varieties can suffer winter freeze back during really hard winters although most of the newer varieties have been selected for more and brighter flowers and improved winter hardiness. Hundreds of thousands of Crape Myrtles are grown every year by the large wholesale nurseries in our state to meet the increasing demand for this colorful heat loving flowering shrub. Many of the newer varieties have even been bred and developed here in Oklahoma by renowned plant breeder Dr. Carl Whitecomb who crosses and trials many acres of new Crape Myrtle every year at his Lacebark Publication farm outside Stillwater. You can plant new Crape Myrtles into your landscape even now in the middle of summer if they have been container grown so that they have a well established root system and you are prepared and committed to water them regularly the rest of this growing season until they are well rooted in their new home.
If you are growing tomato plants in a container you may want to move them to a shady or cooler area for the next six to eight weeks to keep developing new fruit. Although the tomato plant will still grow and can look reasonably well if they get enough water while above 90 degrees, the fruit stops setting on most varieties when above 90 degrees or so. They will still flower but will get much less, if any, fruit when so hot. You can improve your hot summer fruiting if you install shade cloth over your tomato plants if planted in the ground or by moving container tomatoes under the shade of a tree or building to increase summer fruiting.
Don’t forget to walk your garden to stay ahead of summer pest problems, to water your plants as needed to avoid drought stress and too mulch you’re planting to cool the soil, reduce weed competition and to conserve soil moisture while reducing the need to provide extra water to your gardens.
Rodd Moesel serves on the State Board of Oklahoma Farm Bureau and was recently inducted into the Oklahoma Agriculture Hall of Fame. Email garden and landscape questions to rmoesel@americanplant.com.
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