University of Maryland Extension

August Tips & Tasks

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fall webworm caterpillars and webbing
Fall webworm

Outdoor Yard and Garden Tips

  • August is frequently a dry month. If needed, water newly planted trees and shrubs. Allow the water to soak ino 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 worm, 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. 

  • Floating plants such as water lettuce and water hyacinth are tropical plants that can help keep your pond water clean. Their roots act as filters and the plants shade the water thus reducing algal growth.  

  • 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 extreme 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 breakdown and make it difficult to turn the ingredients.

    adult european hornet
    European hornet
    Photo: Jon Yuschock,

  • 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, wood piles, 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. 

Indoor Plant and Insect Tips

  • Propagating African violets is easy using leaf cuttings. Place the cuttings in a soilless mix labeled for African violets. Keep the cuttings moist but not soaking wet and place them in a brightly lit location or under fluorescent lights.

  • Brown scale are sucking insects that attack a wide variety of plants but are common on ficus and indoor citrus plants. Heavy infestations may cause leaf yellowing, stunting, and dieback. They are difficult to control. 

  • Fruit flies can be a problem when fruits and vegetables are allowed to sit for long periods on kitchen counters. Don’t leave fruit on the counter for more than a day or two, thoroughly rinse recycled containers, and be on the lookout to eliminate anything that holds moisture, even mops and sponges. 

  • Contact a pest control professional if yellowjackets are nesting inside the walls or attic of your home.

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