Hotline: 816.833.TREE (8733)

Wednesday, Aug. 7th 2013

August Gardening Calendar

August Gardening Calendar


Weeks 1-4: Continue spraying roses that are susceptible to black spot and other fungus diseases.

Weeks 1-4: Annuals may appear leggy and worn now. These can be cut back hard and fertilized to produce a new flush of bloom.

Weeks 1-4: Deadhead annuals & perennials as needed.

Weeks 1-2: Divide oriental poppies now.

Weeks 1-2: Feed mums, asters and other fall-blooming perennials for the last time.

Weeks 1-2: Roses should receive no further nitrogen fertilizer after August 15th.

Weeks 1-2: Powdery mildew on lilacs is unsightly, but causes no harm and rarely warrants control, though common rose fungicides will prove effective.

Weeks 1-2: Madonna lilies, bleedingheart (Dicentra) and bloodroot (Sanguinaria) can be divided and replanted.

Weeks 1-2: Divide bearded Iris now. Discard old center sections, and borer damaged parts. Replant so tops of rhizomes are just above ground level.

Weeks 1-2: Prune to shape hedges for the last time this season.

Weeks 2-4: Order bulbs now for fall planting.

Weeks 2-4: Evergreens can be planted or transplanted now to ensure good rooting before winter arrives. Water both the plant and the planting site several days before moving.

Weeks 2-4: If you want to grow big dahlia flowers, keep side shoots pinched off and plants watered and fertilized regularly.


Weeks 1-2: Zoysia lawns can receive their final fertilizer application now.

Weeks 1-2: Apply insecticides now for grub control on lawns being damaged by their activity.

Weeks 3-4: Lawns scheduled for renovation this fall should be killed with Roundup now. Have soil tested to determine fertility needs.

Week 4: Dormant lawns should be soaked now to encourage strong fall growth.

Week 4: Verify control of lawn white grubs from earlier insecticide applications.


Weeks 1-4: Compost or till under residues from harvested crops.

Weeks 1-3: Sow seeds of beans, beets, spinach and turnips now for the fall garden. Spinach may germinate better if seeds are refrigerated for one week before planting.

Weeks 1-3: Cure onions in a warm, dry place for 2 weeks before storing.

Week 1: Broccoli, cabbage and cauliflower transplants should be set out now for the fall garden.

Weeks 2-4: Begin planting lettuce and radishes for fall now.

Weeks 3-4: Pinch the growing tips of gourds once adequate fruit set is achieved. This directs energy into ripening fruits, rather than vine production.


Weeks 1-4: Prop up branches of fruit trees that are threatening to break under the weight of a heavy crop.

Weeks 1-3: Protect ripening fruits from birds by covering plants with a netting.

Weeks 1-3: Continue to spray ripening fruits to prevent brown rot fungus.

Week 1: Thornless blackberries are ripening now.

Weeks 2-4: Watch for fall webworm activity now.

Weeks 2-4: Cultivate strawberries. Weed preventers can be applied immediately after fertilizing.

Weeks 2-3: Spray peach and other stone fruits now to protect against peach tree borers.

Weeks 2-3: Fall-bearing red raspberries are ripening now.

Weeks 2-3: Sprays will be necessary to protect late peaches from oriental fruit moth damage.


Weeks 1-4: Soak shrubs periodically during dry spells with enough water to moisten the soil to a depth of 8-10 inches.

Weeks 1-4: Once bagworms reach full size, insecticides are ineffective. Pruning off and burning large bags provides better control.

Weeks 1-2: Spray black locust trees now to protect against damage by the locust borer.

Weeks 2-4: Hummingbirds are migrating through gardens now.

Weeks 2-3: Watch Scotch & Austrian pines now for Zimmerman pine moth damage. Yellowing or browning of branch tips and presence of pitch tubes near leaf whorls are indicative. Prune and destroy infected parts.

Weeks 3-4: Clean out cold frames to prepare for fall use.

Weeks 3-4: Monitor plants for spider mite activity. Hose these pests off with a forceful spray of water.

Weeks 3-4: 2nd generation pine needle scale crawlers may be present on Mugo pine now.


3 Comments on “August Gardening Calendar”

  1. Pam Says:

    What is the best remedy for black spot on roses? I tried the vinegar and water and it did nothing. I pick up the bad leaves.

  2. mggkcblog Says:

    Black Spot is a fungus that likes rain and damp weather and can be very hard to control. It sounds like they’d like to avoid chemicals. Keeping the rose area clean is a good step. Pick off diseased leaves and pick up the dropped diseased leaves because the next time you water or it rains water droplets can hit the ground picking up fungus from fallen leaves and splash back on the rose bush to reinfect it.

    A good fungicide can help control Black Spot, following label directions for frequency and strength when mixing the spray. Be sure to drench the whole rose bush, underside of leaves too, and even surrounding soil where fungus may be lurking. Avoid spraying when temperatures reach mid-80s and hotter as the spray could burn a rose bush. Caution — wear gloves and protective gear when using chemicals.

    A product called Mancozeb or Manzate — same product but the latter is dry and the first is “flowable” (a thick liquid) that’s easier to mix. Apply three times, waiting a few days between sprayings. Works best sprayed at first sign of Black Spot. The down side is cost but a pint goes a long way. Depending how many rose bushes grown, it’s well worth it to be rid of the problem. on line is a good source for various Black Spot products and fungicides are on sale right now.

    Wednesday is spray day in the Laura Conyers Smith Rose Garden in Loose Park.

    Hope that helps–

  3. Pam Says:

    Thank you very much!

Leave a Reply

You must be logged in to post a comment.

University of Missouri Extension Master Gardener Program