August/September Gardening Tips

Outdoor yard and garden tips

• August is frequently a dry month. If needed, water newly planted trees and shrubs. Allow the water to soak into the surrounding soil and the root ball. 
• Fall webworm is a late summer caterpillar 1-2 inch long and hairy caterpillar. It creates large tent-like webbing on the ends of branches of various shade trees and shrubs. Unsightly but causes little damage. 
• Numerous caterpillars, including leafrollers, orange striped oak worms, green-striped maple worms, oak skeletonizers, and sawflies are feeding on various shade trees. No controls are necessary. If you see saddleback caterpillars or other stinging caterpillars, leave them be. 
• Late August through September is a good time to transplant, divide and plant perennials. Be sure to keep them well-watered during dry periods.
• Remove hosta leaves that are yellowing or scorched (brown leaf margins). In many cases, this is caused by a combination of hot, dry conditions, or diseases like alternaria and anthracnose (Colletotrichum). If disease-related, leaf removal will help to slow down disease progression.   
• Southern blight, a significant soil-borne disease, is promoted by hot and humid weather. It attacks a wide range of annuals, groundcovers, and perennials including thyme, coneflower, coreopsis, and black-eyed Susan. Affected lower stems turn brown or black, foliage wilts, and plants will eventually dry up and die. 
• Avoid mowing your lawn during extremely dry and hot weather. Mowing wounds grass blades creating more surface area for plant moisture to escape. 
• Brown patch is a common fungal disease of tall fescue lawns that creates thin, brown areas. Grasses will green up and recover in the fall. No chemical controls are recommended. This disease is typically worse on over-fertilized and irrigated lawns.
• Submit a soil sample for testing if planning a lawn renovation project in the fall. 
• Harvest tomatoes when they first change color and ripen them on a kitchen counter.
• Brown and green Southern stink bugs are active on tomatoes and peppers. They feed on the fruits producing a yellow or white “cloudy spot” directly under the fruit skin. These spots become hard but can be cut out with a sharp knife and won’t affect flavor. If stink bugs are a problem, try handpicking first or spraying pyrethrum.  The spray must contact the stinkbugs to be effective.
• Harvest and preserve tarragon, rosemary, basil, sage, and other culinary herbs. Herb leaves are most intensely flavored right before the plant blooms. 
• Remove and dispose of all rotted or dropped fruits and foliage from trees, vines, and bushes. This will help reduce the overwintering of diseases and insect pests that will attack your fruit plants next season.
• Grass clippings and spent plants from the flower and vegetable garden provide a good source of high nitrogen green materials for the compost pile. Fallen leaves and old straw mulch are good sources of high carbon brown materials. Shred your materials with a lawnmower, string trimmer, or machete to speed up the breakdown process. Keep sticks, roots, and woody stems out of your compost pile. They take too long to break down and make it difficult to turn the ingredients.
• European hornets sometimes strip the bark off shrubs (especially lilac) and trees. This behavior rarely does harm. The European hornet is a large yellow and brown hornet that nests in cavities in trees, stumps, woodpiles, sheds, etc., and feeds on insects. Unlike most other wasps and hornets this one is a night flyer.
• Try to ignore hornet, bee, and wasp nests found outside, especially if they are located in a tree or an isolated area. These are beneficial creatures that will not sting unless disturbed or provoked. However, if a hornet or yellowjacket nest is a threatening nuisance such as under your deck or near a door you can destroy it with a labeled wasp and hornet spray at night. Read and follow all label directions.

Information credit:  The University of Maryland Extension