August Care for Annuals & Biennials

Cary, NC

Our Carolina summers sure can take a toll on the average homeowner's yard and landscape. Although a few small signs of cooler days are starting to make an appearance, we still have a little more summertime weather to get through. If your annual and biennial planting beds and containers are looking a little worse for wear right about now, here's a few gardening tips and tricks to keep them looking in top form during this last bit of summer heat and humidity.

Care For Your Annuals

Do not disturb the soil in your flower beds during these hot August days. Loosening the soil due to cultivation can damage those tender surface roots and increase water loss from the soil. You may notice that after you break up the soil around them, plants often look much worse. So just leave well enough alone for now.

Inspect the mulch in flower beds. If wind, rain, and natural decay have reduced its thickness to an inch or less, apply more mulch to raise the level to 2 to 3 inches between plants, but only about 1/2" around the bases of the plants.

If your bedding plants look bedraggled, clear out the annuals that have finished blooming or are overgrown.


Check the soil in flower beds to determine if you need to water. Water deeply to wet the entire root zone of the plants.  Avoid wetting the leaves to reduce the risk of fungal diseases such as leaf spots and powdery mildew.

Container-grown flowers can dry out quickly, especially when located in full sun. Check the moisture level in pots daily and water when needed. Be sure to water long enough so that it runs out of the drainage holes. Keep in mind that porous clay pots will dry out more quickly than plastic or glazed pots. Also, small pots will dry out faster than large planters.

Check on the water needs of hanging pots and baskets daily. Wind and sun dry them much more quickly than plants in other kinds of containers.


If they haven't been fertilized in over six weeks, leggy plants that have been cut back will benefit from a light feeding of fast-release fertilizer. Use a water soluble fertilizer such as 20-20-20, following label directions.

Pest Control

Be on the lookout for aphids and spider mites. You can remove these pests with a strong spray of water, or resort to a pesticide if their numbers are too high and damage is great. However, if these plants are going to be removed and replaced by cool-season annuals, spraying with a pesticide may be unnecessary. Simply remove and discard heavily infested plants instead.


Control weeds by hand-pulling and maintaining a shallow layer of mulch. Prevent weeds from going to seed by removing the flowers. Keeping the beds weed-free will prevent competition for water and nutrients, and will also remove overwintering sites for those nasty spider mites.

For more gardening advice and tips, ask the friendly experts at Garden Supply Co. They are on hand seven days a week with help for all your gardening questions. Hope to see you all soon!