Heather Kirk-Ballard

LSU AgCenter Horticulturist

(08/02/19) August is here. School and football are almost upon us, and we are eagerly anticipating cooler fall weather. Here are some things you should be doing this month in the garden.

Prune your ever-blooming roses back about one-third of their height in late August to early September to encourage new blooms for October and November. Remove all the dead canes and diseased wood. Remember when removing diseased material to rinse your pruners in a 10% bleach solution and then water before making any new cuts. This will help prevent the transfer of disease to other parts of the plant or other plants in the garden. There no need to prune once-blooming roses because you may reduce the blooms for next year. You may remove any dead or diseased canes, however.

After trimming your roses, it is a great time to fertilize immediately or shortly after with a rose or general-purpose or organic fertilizer at the recommended rate. The extra nutrients will encourage vigorous new growth and enhance flowering over the next three months.

Spray roses for blackspot, powdery mildew and other fungal diseases. You may choose to use triforine, thiophanate methyl or copper oleate. Follow manufacturer’s directions carefully. Rake up and remove all fallen leaves to prevent further infection of rose bushes and dispose of them in the trash. If you compost, avoid putting the diseased leaves there.

Now is also a good time for bed maintenance. Many of the ornamental bedding plants have either grown out of control with the warm and wet weather, or they have just tuckered themselves out in all the heat.

August is a good time to cut back and stake tall plants and deadhead the spent flowers on annuals, ground covers, perennials and vines that are still thriving but have gotten too large. It is also a good time to remove anything that just no longer looks good and think about a good replacement for the fall as the temperatures cool. Hold up on planting right away. Wait until temperatures cool.

You can cut back bedding plants that still look good but may have become leggy to encourage blooming through fall by removing one third to one half of the plant material. This will help to bring back a fuller-looking plant and encourage blooming throughout the fall. This includes begonias, blue daze, coleus, impatiens, lantana, pentas, periwinkle, ruellia, verbena and a host of other bedding plants.

Consider another application of fertilizer for your lawn. Your third and final application of fertilizer can be made in August for bermudagrass, St. Augustine grass and Zoysia. For centipede it’s not necessary, but you may make another application if you wish.

Be on the lookout for chinch bug damage in your lawn, especially in St. Augustine grass. Hot, dry weather is ideal for the chinch bug that feeds on sap from grass stems and stolons. Look for grass that is yellow-brown or straw looking and eventually dies. Good cultural practices can help minimize the damage with proper fertilization, irrigation and mowing. If the problem has gotten out of control, consider insecticide applications of bifenthrin, carbaryl or permethrin. Follow the label instructions carefully.

Fire ants can also be a real problem at this time. They will not hurt your lawn, but they can sometime kill the turf where mounds are growing and block out the sun. If you have small children or have severe allergies to ants, you can apply granular dursban or diazainon.

Transplant fall tomato plants into your garden by mid-August for north Louisiana and the first week of September for south Louisiana. You should be checking often for insects and disease as they are more prevalent during fall. Treat if needed. Consult local extension specialists in your area for more information. Some suggested cultivars for fall production are Florida 91, Phoenix, Sun Leaper, Solar Set, Sunmaster and Talladega.

In the vegetable garden, remove spent summer tomato, pepper, eggplant and other plants that have tuckered out and plant seeds of broccoli, Brussels sprouts, cabbage, cauliflower, collard greens, cucumber, kale, lettuces, lima beans, Swiss chard, Southern peas, shallots, squashes and turnips. If your spring-planted eggplant, pepper plants and okra still look good, let them continue to grow. They often produce another fall crop. I get excited just thinking of my fall vegetable garden.

August is an active month for hurricanes. Be sure to check large trees for decayed limbs and trunks and carefully remove them if you are able to do so from the ground or with a small stepladder. Never cut around power lines. Also look for leaning trees. Consider having trees that look unhealthy pruned or removed by a licensed arborist before a storm. If one is on the way, be sure to remove any loose items from the lawn and patios that could be caught and carried by heavy winds and lodged into windows or damage the house.

Now is the time to harvest pears as they finish up by late summer. Ripened pears can be picked when they begin to turn yellow to red. For the best quality, allow them to ripen on the tree. However, you can harvest hard and firm pears to make a pear butter or jelly at this time.

Start planning and selecting trees and shrubs for fall planting. But hold off until the weather cools to plant these. Planted now, they will be stressed in the heat and will require a great deal more watering and care to get them established. It’s best to wait until cooler temperatures arrive. Container plants can, however, be successfully planted with a great deal more TLC if you want to plant now.

I’m getting excited for the purple and gold chrysanthemums. They’ll be in the nurseries before you know it, just in time for some fall tailgating.

Use sharp bypass-type hand pruners when pruning roses to make clean cuts and minimize damage to the stems. Photo by Rick Bogren/LSU AgCenter

Ant-sized chinch bugs feed by sucking the sap from the grass, causing it to dry out and die. Look closely at the blades of grass in the affected dead areas and see if they look rolled up lengthwise, indicating chinch bug damage. AgCenter archive photo by Dan Gill

Tomato transplants for a fall crop can be found in nurseries in August. Photo by Kathryn Fontenot/LSU AgCenter