- Provide 1 inch of water per week. Adjust the amount of water based upon rainfall and temperatures. Water more often in very hot weather and less frequently in cooler temperatures.
- Now is still a good time to plant balled and burlapped and container-grown trees and shrubs. Apply a 2 to 3-inch layer of shredded mulch around shrubs to conserve moisture and keep roots cool.
- Make sure your plants receive enough moisture during this hot and dry month: 1 inch of water per week.
- When cutting gladiola stems leave as much foliage on the plant as you can.
- Continue to weed and water flower beds.
- Flowers such as alyssum, lobelia, snapdragons and dianthus may slow flowering in the intense heat; however, once the weather turns cooler, they will start up again.
- Remove spotted leaves and discolored flowers to decrease fungal diseases in your garden.
- Dig and divide overgrown iris, poppies and other spring blooming perennials.
- Remove suckers that appear at the base of roses. Cut them off below ground to reduce the chance of re-sprouting.
- It is still a good time to plant potted roses.
- Watch for aphids and mites. Spray plants with a strong blast of water to knock these pests off the plants or use insecticidal soap for larger populations.
- Check tree trunks for female gypsy moths. The white, flightless moths crawl up the trunk to mate and lay eggs. Remove and destroy the female and egg masses as they are found.
- Avoid pruning oaks and honey locusts as the open wounds from the pruning cuts can increase the risk of disease.
- Save major tree pruning for fall.
- Moisture loving trees, such as paper birch (Betula papyrifera), may need to be watered once a week during dry weather.
- Inspect the landscape for metallic green and brown Japanese beetles. Pick by hand and destroy small populations and for heavy populations make a fall application of a soil systemic such as Bayer® Tree and Shrub Systemic to kill next year’s beetle population.
- Water your garden early in the morning to reduce the risk of disease and water loss to evaporation.
- Stay on top of weeding in your garden.
- Cut away old raspberry canes and thin side shoots on new canes.
- You can still plant radishes, lettuce, spinach and beets for a fall harvest.
- Keep your lawn well-watered.
- Start new lawns and repair old ones in mid to late August. The soil is warm so the seeds will germinate quickly. The temperatures will start cooling off and are perfect for growing grass.
- Drought-stressed and newly seeded lawns may become infected with rust. You may notice an orange residue on your shoes after walking across the lawn. The symptoms will soon disappear, and the grass will begin to recover on its own. Treatment is usually not needed.
- For winter houseplants, take cuttings of geraniums, coleus, basil and other plants.
- Cut back declining plants to improve the appearance of your perennial garden.
- Do not prune butterfly bushes (Buddleja), blue mist shrub (Caryopteris), and Russian sage (Perovskia). Enjoy the late season blooms and allow plants to start hardening off for the winter.
- Cut back short-lived perennials such as blanket flowers (Gaillardia) and pincushion flower (Scabiosa). Late-season pruning stimulates new green growth and helps extend the plant’s life.
- Check bee balm (Monarda didyma) tall garden phlox (Phlox paniculata) and other perennials for signs of white, powdery mildew. Consider relocating infected plants into an area with full sun and good air circulation. Plant mildew-resistant cultivars.
- Dig gladiola for winter storage only after the foliage has yellowed and died naturally.
- Allow lily foliage to turn yellow and die naturally. Cut, do not pull, the leaves.
- Protect melons from rot by mulching the soil under the fruit.
- Dig onions when the tops fall over and begin to dry. Harvest the onions started from sets first.
- Harvest peppers when the fruits are firm and fully colored. Separate mild and hot peppers to avoid mix-ups later on.
- Harvest sweet pickle cucumbers when they are 1 ½ to 2 ½ inches long. Harvest dill pickles when they are 3 to 4 inches in length. Harvest slicing cucumbers when they are 6 to 9 inches long.
- Harvest tomatoes when they are fully colored.
- Share fresh produce with friends and family.
- Remove thatch from the lawn if it is more than ½ inch thick.
- Divide spring flowering perennials and give some cuttings to friends. You can dig and divide most perennials anytime as long as you give them proper post-planting care.
- Watch your trees for early signs of fall color. This is a sign your tree is in distress. Proper watering and care may help a stressed tree.
- Set out chrysanthemum plants now for fall color in the next two months.
- Plant pansies, violas, flowering kale and colorful hardy garden mums for added color in your garden or front entryway.
Minnich, Jerry. The Wisconsin Garden Guide – The Complete Guide to Vegetables, Flowers, Herbs, Fruit, & Nuts, Lawn & Landscaping, Indoor Gardening. 3rd ed. Madison: Prairie Oak, 1995. Print.
Myers, Melinda. Month by Month Gardening in Wisconsin: What to Do Each Month to Have a Beautiful Garden All Year. Franklin: Cool Springs, 2006. Print.