LSU AgCenter Horticulturist
July can be a tough month for plants. Heat and high humidity often lead to an increase in disease and insect pressures. Despite the increased stress, many plants are still performing well — and July can be a productive month for us as gardeners.
Throughout the U.S., National Smart Irrigation Month is observed in July. This program was designed to promote the conservation of one of our most precious resources: water. Efficient irrigation offers social, economic and environmental benefits, and you can learn more about implementing these tools and strategies at www.irrigation.org.
In the vegetable garden, continue to fertilize and irrigate vegetables to keep them going through the summer when rain is scarce. Pull up cucumbers, squash and tomatoes that have stopped producing, and plant heat-set tomatoes and bell peppers for fall harvest. Direct seed okra, Southern peas, cucumbers, squash, cantaloupe and watermelons throughout July. Also order your fall vegetable garden seeds, including broccoli, Brussels sprouts, cauliflower, Chinese cabbage, cabbage, leafy greens and all your root crops.
Start planting pumpkin seeds for pumpkin carving in the fall. Most pumpkins need between 70 and 120 days before they’re ready to harvest. Try giant pumpkin varieties such as Atlantic Giant, Prize Winner, Big Moon and Big Max. Good large varieties, which are 10 to 30 pounds, include Aspen, Howden, Spirit, Gold Rush, Cargo, Connecticut Fields and Jumpin Jack. New Moon and Lumina are both white.
Medium-sized, 5-to-10-pound varieties are Autumn Gold, Big Autumn, Charisma, Cougar, Jack-o-Lantern, Neon and Peek a Boo. Small-sized pumpkins are Early Abundance (yellow), Darling, Sunlight (yellow to white), Baby Bear, Casperita, Gooligan (white), Hooligan and Jack Be Little.
In the lawn, chinch bugs, mole crickets and sod webworms can be a problem during hot, dry weather, especially in St. Augustinegrass. Control with insecticides containing the active ingredients carbaryl, cyfluthrin or imidacloprid — or skip the insecticide and leave the bugs for the birds.
You can plant warm-season grasses throughout the summer. Planting in July will provide better opportunities for lawns to become established before going dormant in the winter. If you have bermudagrass, zoysia or St. Augustinegrass lawns that were fertilized in spring, you can now make a second application. It is not recommended to reapply fertilizer for centipedegrass.
It’s time to stop using weed killers in the lawn during these hot summer months. Applying these products when it’s over 85 degrees Fahrenheit will cause injury to lawns.
Mowing will be the most common practice in the home landscape this month. Grasses thrive and grow aggressively in summertime. Be sure to cut your lawn at proper heights once a week or every other week, depending on growth and rain activity. Bermudagrass should be cut to 1 to 1 1/2 inches; centipedegrass, 1 to 2 inches; St. Augustinegrass, 2 to 3 inches; and zoysia, ½ to 1 1/2 inches. It is still a good time to dethatch and aerate your lawns.
In the landscape beds, plant heat-loving tropicals such as hibiscus, cassia, ixora, canna, tibouchina, mandevilla, duranta, angel trumpet, plumeria, bird-of-paradise, bougainvillea and gingers. They thrive in our climate, and the vibrant bloom colors are a gorgeous addition to the landscape. To keep tropical blooming plants year-round, plant them in containers. Many tropical plants are not hardy enough to withstand our winters.
Increasing heat and water requirements make planting shrubs and trees this month more challenging; however, container plants can still be installed. You can plant palms this month. Keep young trees watered and mulched at about 1 foot surrounding the trunk to help control weeds and prevent damage to thin bark from string trimmers and mowers. Be aware of the need for more frequent watering and fertilizer requirements, as plants use water faster when it is hot and they are actively growing.
Control aphids on crape myrtles and lace bugs on azaleas and lantana. For roses, continue a spray program that includes both a fungicide for black spot control and an insecticide to control pests. Ever-blooming roses can and should be trimmed for a new fall flush of blooms.
Now is the time to harvest muscadines, grapes and figs. There are some common fungal disease problems in figs seen this time of year. Thread blight and fig leaf rust cause leaf spotting and scorch in late summer and fall. There are no EPA-approved fungicides for use on figs in Louisiana. The best way to manage these is with good cultural practices. Plants should be spaced to provide good air circulation and water at the root zone. Remove fallen, infected leaves and throw them away.
In the lawn, chinch bugs can be a problem during hot, dry weather. Photo by Ron Strahan/LSU AgCenter
Fig harvest season begins in July. Photo by Heather Kirk-Ballard/LSU AgCenter
Pumpkins are planted in the summertime, typically July for an autumn harvest. Photo by Heather Kirk-Ballard/LSU AgCenter