Wisconsin Yard and Garden Tips

By Sharon Morrisey, Consumer Horticulture Agent, Milwaukee County UW-Extension

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. (465)

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. (349)

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. This is an organic product but may be hard to find. There are newer, more available products containing the active ingredient spinosid that are also organic. The synthetic insecticide carbaryl (Sevin) can also be used. (493)

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. (506)

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.

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. (495)

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. (487)

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. (449, 450)

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.

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 in mid-October, Memorial Day and Labor Day. Use a slow release product for the late season application. (530)

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.