August Garden Tips

August...gardening chores are essentially at a lull.  But, there are plenty of chores for the avid gardener to do.  Try to perform major chores during the cooler days and enjoy yourself.

Indoor Plants

  • Look for insect damage on your houseplants.  Control pests on your houseplants outside where it is easier.
  • Make sure houseplants placed outdoors have plenty of water.

Lawns and Landscaping

  • Reducing lawn size can significantly save you water.  Consider eliminating hard to water areas like narrow strips or irregularly shaped areas.
  • Fertilize warm-season grasses in the summer and coo-season grasses in the fall.
  • Turf grasses need water when they lay flat when walked on, and foot prints remain visible.  The over-all color may turn gray-green also.
  • Water lawns early in the morning on hot days.  Set your sprinkler to produce large droplets instead of a fine mist to help prevent evaporation.  Make sure you give your lawn at least one inch of water once a week.
  • Now is a good time to plan for landscaping in the fall.  Decide on what plants to purchase and where to plant them.
  • Mow your lawn removing no more than 1/3 of the growth.
  • Plan to rejuvenate or plant a new lawn in the fall.

Perennials, Annuals and Bulbs

  • ​Late-blooming perennials, such as Helianthus, Helenium, Heliopsis, and Rudbeckia, make great color in fall.
  • Start selecting your favorite bulb varieties.  It is time to order your bulbs for planting in the fall.
  • Avoid deep cultivation in your flower beds during hot dry days.  This may reduce water uptake by increasing loss of soil water and damaging surface roots.
  • This is the best time to purchase chrysanthemums when they become available.  Choose plants that are just coming into bud.
  • Plant autumn-flowering bulbs as soon as they become available at garden centers.
  • Don't let hybrid, annual flowers go to seed.  This will weaken the plant and reduce blooms.
  • Keep roots of lilies cool for best growth.  You may have to mulch around the plants.
  • Select a site for spring flowering bulbs.  For daffodils, dig the soil 12 inches deep in a sunny location and work in fertilizer and compost.
  • Container-grown plants may need water several times a day.  Also avoid water stress which may cause nutrient leaching.
  • Remove bedding plants that have finished blooming.  Replace them wit hardy annuals or mums.
  • Replace container annuals that are past their prime with new ones, mixing new soil with the old.  Add a slow release fertilizer following the manufacturer's  instructions.
  • Plan changes in your perennial plantings.  Autumn is the best time for moving and dividing perennials.
  • Colorful plastic golf tees can be stuck in the ground to mark the location of dormant plants such as spring bulbs or perennials.
  • Check on water needs of hanging baskets daily in the summer.  Wind and sun dry them much more quickly than other containers.
  • Clean up fallen rose and peony leaves.  They can harbor disease and insect pests over the winter if allowed to remain on the ground.
  • Divide older Bearded Iris rhizomes.  Cut out the woody parts and replant the rest.
  • Plant fall crocuses now and crown imperials from now until October.
  • Add several inches of mulch to Asiatic lilies.  This will keep the roots cool, protect them from heat and deter weed growth.
  • Dig up your ranunculus and anemone to store for the winter if you haven't already done so.  In warmer zones they can be left in the ground.  Just apply a light mulch in fall.
  • In late August you can dig up overcrowded lily-of-the-valley bulbs that grew poorly.  Gently separate each plant and replant individually.

Trees, Shrubs and Groundcovers

  • ​Mulched shrubs may not develop mature stem tissue where they touch the mulch.  Remove about 2-3 inches from the base of the stems in mid-August to harden them off.
  • Avoid deep cultivation around evergreens that have roots near the ground surface to prevent damage.
  • Check soil pH around azaleas if they look pale-green to yellow.  They need acidic soil to maintain green color.  Sulfur will reduce soil pH.
  • Root cuttings of woody shrubs and evergreens, such as azaleas, holly, and hydrangea.
  • Inspect trunks and branches of dogwood for injured bark or fine dust being pushed from burrows in trunks by borers.  Contact the Extension Office for advice.


  • ​Mound soil over the lateral or brace roots of corn stalks for extra support against strong winds.
  • Pick summer squash and zucchini every day or two to keep the plants producing.
  • Remove old plants which have stopped producing to eliminate a shelter for insects and disease organisms.
  • Many herbs self-sow if the flowers are not removed.  Dill produce seeds that fall around the parent plant and come up as volunteers the following spring.
  • To reduce the number of pests on your fruit tree for the coming year, pick up and destroy all fallen fruit.
  • Bt (Bacillus thuringiensis) is used by many gardeners to protect cole crops from chewing caterpillars.
  • Harvest sweet corn by pulling and twisting downwards.
  • Bend over the tops of your cooking onions to prepare for lifting them.
  • Harvest peas and broad beans before pods get tough.
  • Lift maincrop potatoes after the stems have died.
  • Harvest artichokes while the scales are still tight.
  • Seed winter vegetables now.


  • ​Before using a pesticide, diagnose the problem.  Consider factors such as severe heat or cold, waterlogging or drought, mower damage and carelessly applied herbicides.
  • Buy only those fertilizers with a guaranteed analysis and those proved by university research.
  • Remember that dusts cannot be applied as precisely as sprays, and they may drift to non-target areas.
  • Spider mites leave webs on the underside of leaves that contain their eggs.  A grayish stippled appearance of leaves infested with spider mites is caused by their feeding on plant juices.  These mites thrive in hot, dry weather.  Hose off the fokiage for minor infestations.  For severe problems, check with the Extension Office.
  • If you use pesticides, water your plants thoroughly to prevent the concentration of the chemical from causing plant damage.
  • Remove plants that have gone past their prime to prevent diseases and pest problems.
  • Whenever you apply pesticides, adhere strictly to the directions on the package.  Do not spray when temperatures are over 85 degrees F or when it is windy.
  • White flies are attracted to yellow, so use yellow sticky boards to reduce their populations.
  • Do not add weeds with mature seed heads to the compost pile.  Many weed seeds can remain viable and germinate next year when the compost is used.
  • Don't forget to moisten your compost regularly to prevent flies from breeding in it.

August Tips

© 2020 by COMPEDS. All rights reserved.

  • Facebook