August is summer’s swan song. If its normal, we can expect some very hot, dry weather this month. Water early in the day and use mulches to hold in moisture.

The plant pests are really having their way with our flowers and vegetables right now. Accurate, timely identification and treatment are critical. For help with plant problems or questions on how to grow indoor and outdoor plants, the UW-Extension in the four southeastern counties provide Horticulture Help Lines. In Milwaukee County call 414-290-2410. In Waukesha call 262-548-7779. In Racine call 262-886-8451. In Kenosha call 262- 857-1942. UW-Extension also holds walk-in plant clinics at several sites including Boerner Botanical Gardens in Hales Corners in Whitnall Park. The UWEX Horticulture Center is open Monday through Friday from 10:00 – 2:00 and on Thursday evenings from 4:00 – 6:00.

From July 31st through August 10th, visit the UW-Extension Master Gardener Volunteers at the Wisconsin State Fair in their “Model Backyard” exhibit in the DNR area. There is a native plants area, a butterfly garden, working compost bins, a cactus garden, a rain garden and a demonstration for Access to Lifelong Gardening. So, stop by and say hello.

Help on the web is available year around through the UW-Extension Horticulture Team website at wihort.uwex.edu . From there you can print Wisconsin Garden Facts factsheets, UW-Extension publications, and InfoSource scripts. Use the links to go to many other useful sites.

Numbers in parenthesis after entries in this month's garden calendar are for the UW-Extension’s InfoSource educational message system. It is available on-line at infosource.uwex.edu.


 

First Week

The last date to sow sweet corn for the year is August 1st.

For late crops of beets, bush beans, carrots, Chinese cabbage, cucumbers, kohlrabi, and onion sets, continue sowing seeds until August 15th. Peas and collards can be seeded again now, too.

Aphids can continue to show up all season long. Dislodge them with a strong blast of water or use insecticidal soap (not dish soap) when first noticed.

Continue controlling stripped and spotted cucumber beetles which spread bacterial wilt to cucumbers, squashes, melons, and gourds. Weekly dusts or sprays of rotenone, carbaryl (Sevin) or permethrin (Eight) are effective but only if insects are present. Apply late in the day after flowers close and bees are not present. Remove infected, wilted plants immediately.


Colorado potato beetle adults are back for a second generation. Since these distinctive, globular, yellow and black striped insects are so easily seen they can either be removed by hand or sprayed. A specific strain of B.t. called M-trak is effective against these beetles while they are still young. The insecticide carbaryl (Sevin) can also be used.

After the last raspberry harvest for the year, prepare for next year while also avoiding diseases by pruning out old flowering canes leaving only 3-4 young canes per foot of row. Wait until spring to prune back shoot tips.

Watch for the appearance of fall webworm webs on limbs of trees and shrubs. Cut out the tents or spray while the larvae inside are still young using the biological insecticide B.t. (Bacillus thuringiensis) sold as Dipel, Thuricide, or Bactur. Once the larvae are over 1 inch long control is not effective or necessary.

Avoid pruning trees and shrubs since doing so this late in the season can stimulate new growth that will not harden off in time for the cold winter weather ahead. Delay pruning until the end of the dormant season early next spring. Late in the season when trees and shrubs are going dormant, wounds heal very slowly. Tender wound tissue can also be killed by freezing temperatures.

 

Second Week

Harvest vegetables such as tomatoes and melons regularly and frequently to avoid
overripe fruit which attracts picnic beetles.

Harvest onions and garlic as the tops dry and fall over. Braid garlic tops and hang in a cool, dry place. Cut onion tops back to 1" and dry thoroughly before storing. Use any damaged produce immediately.

Fall bearing raspberries will begin ripening. Pick fruit as soon as ripe since overripe fruit attracts picnic beetles which will seriously damage fruit.

Make the second application of fertilizer on new plantings of June bearing strawberries. Apply 3 lbs. of 10-10-10 per 100 feet of row.

This is a good time to order and plant spring flowering bulbs for next year's early flower display. Plan for different flowering times to extend the season. As with most flowers, they are best displayed in masses of all one type and color rather than in mixtures which can be busy and garish.

 

Third Week

From now until September 20th is the ideal time to seed or sod new lawns or to repair diseased or damaged areas of your yard. Prepare areas with an application of the herbicide glyphosate 10 days before seeding or sodding. Rototill the area to a depth of 6-8". Work in extra organic matter and fertilizer. Level and rake smooth. Rake seeded areas lightly to bury seed about 1/8 inch. Tamp to assure good seed to soil contact. Cover newly seeded areas with a very light layer of straw to help retain moisture. Do not allow to dry out until all grass has emerged - about 15 days. Mow as soon as the new grass is 3 - 31/2 inches tall.
    

Seeds can again be sown for a late crop of leaf lettuce, mustard greens, Swiss chard and spinach.

If you haven't already done so, divide irises now before their second flush of root growth which will occur during fall's cool, moist weather. Examine rhizomes for borer tunnels and soft rot. Destroy all infected plants. Replant by barely covering the small sections of rhizome each with a fan of leaves and some roots. Cut leaves back by 2/3's.
    

If you want flowering plants indoors this winter of fuschia, wax begonia, impatiens, geraniums, and coleus, root cuttings now in vermiculite or perlite. Use rooting hormone powder on cut stem ends. Keep flats or pots in a calm, shady spot outdoors until mid-September.

 

 Fourth Week

In the flower garden, continue deadheading which will allow plants to use energy reserves for a final flower display. If there are signs of diseases, remove all leaf litter and spent plants to prevent the spread of spores.

Prepare for a Labor Day fertilizer application to the lawn unless you will be doing a weed n' feed treatment later in September. Mid-September is the only time of year when weed and feed products are actually timed right for both the weed control and the fertilization. If you do three applications of fertilizer per year, they should be at Halloween, Memorial Day and Labor Day. Use a slow release product for the late season application.


Late season problems on deciduous plants should be of lesser concern than those that appeared earlier in the season since leaves will soon change color and drop anyway. Diseased leaves should be removed promptly to minimize pest problems next year.