September a good time to plant, divide peonies
If you have holes in your perennial borders or tired-looking containers from the hot summer, look for enhancements to install now. Aster and pansies blend well into perennial borders and can enhance baskets and containers.
Peonies are dependable, long-living, hardy perennials. Their neat foliage stays green from spring until frost, and follows large, showy blooms. They do best in full sun, although they can tolerate partial shade. Flowering is reduced if placed in the shade. September is a good time to plant peonies as well as divide and transplant existing ones. Lift roots carefully and use a sharp tool to cut the large, fleshy roots into smaller pieces. Be careful not to make these pieces too small - each section should have at least three eyes. The eyes are reddish growing buds that emerge from the top of the roots. You will find them in spring and fall. Set these divisions an inch or two below ground. If planted too deeply, peonies will often fail to flower for several years.
Powdery mildew (a disease that causes a grayish, powdery film on leaves) is present now. Common plants that can get powdery mildew are lilac, phlox, bee balm, zinnia and nannyberry viburnum. This disease typically occurs in the late summer when the weather is warm and humid. Fungicides can help control powdery mildew if applied before the infection becomes severe. In most cases there is no need to apply any controls for powdery mildew this late in the season. Other options include selecting more mildew-resistant varieties, or moving the infected plants to an area of the garden that has better air circulation and full sun.
Plants that prefer acidic soil conditions like rhododendron and azalea can benefit from an application of granular sulfur to the soil in fall. Avoid contact with the sulfur by wearing latex gloves and keeping dust out of your eyes. Apply to soil and gently scratch in. Sulfur works slowly in the soil and repeated applications may be necessary from year to year.
It is time to protect the trunks of smooth-barked trees like young maples from deer rubs. Deer rub the velvet off their antlers in late summer and early fall and will often use the trunks of smooth-barked trees. This can damage the bark and even kill trees if damage goes all around the trunk. Wrap the trunks with tree wrap, chicken wire or plastic snow fencing to a height of 5 feet to help protect the tree. This protection can be removed in early spring.
Try to buy mums and asters when their flower buds are just beginning to open. The color will last longer in your garden. Generally mums and asters will last for 4-6 weeks depending on weather. Season-extender mums can keep color going through October and sometimes later depending on weather. If you are planting mums into a shady site then it is best to wait until the flowers are open before planting.
It is time to start thinking about the indoor herb garden. Before frost, carefully lift and pot small herb plants or large perennials such as rosemary or lemon verbena to bring inside. After lifting them from the ground, you may want to keep them outside for a few days in a partially shaded spot with even moisture. This will help them adjust to a move indoors. The shock from moving plants from outside to inside can cause some yellowing of leaves. Once inside, keep the herbs in a sunny window.
A spring and summer with a lot of rain and humidity has increased problems with foliar diseases. Some crabapples that are typically resistant to apple scab have been affected because of the weather and look to be in worse condition than last month - some have lost many or most of their leaves. These trees are under stress but not necessarily dead. There are no treatments to be made at this time as preventive sprays for apple scab are done in spring. Provide supplemental water as needed and fertilize in spring to increase the vigor of the trees.
PlantingFall is a great time to plant and transplant trees and shrubs. In general, trees and shrubs do not need to be pruned when transplanted to compensate for loss of roots during digging. Fall conditions, which include warm soil, moderate air temperatures and rain, help plants re-establish their root systems. Evergreens benefit from planting early in the fall to minimize chances of winter burn. Try to get them planted before the middle of October and continue watering them weekly or as needed until the ground is frozen. Mulch is also important for fall plantings - use 2 to 3 inches of mulch, keeping it away from the crown (base) of the plants. Good soil preparation is important for a successful planting. It is best to amend the entire planting area or bed instead of individual holes. Evenly incorporate 2 to 3 inches of compost into existing garden soil.LawnsFertilize your lawn in early September to improve the color and vigor of grass. Nitrogen is the nutrient required the most although too much nitrogen can cause excessive top growth and other problems. In most cases a rate of one pound of nitrogen per 1000 square feet of lawn is adequate. Many soils in Chicago area have adequate levels of phosphorus so it is likely not needed for your lawn. Some villages ban the use of phosphorus to improve water quality as it can fuel algae growth in lakes and streams. Crab grass may be evident in your lawn now, especially if it has been neglected. This annual weedy grass seeds readily in the fall. Keep it closely cut to prevent seed formation or pull it out by hand. Herbicide treatments will have little effect when crab grass has set seed. Make note of bad areas in your lawn and apply a pre-emergent herbicide (one that prevents weed seeds from germinating) in early spring before lilacs flower. Autumn is a good time to core aerate your lawn to relieve soil compaction and reduce thatch. It also provides an opportunity for overseeding to thicken up your lawn. Core aerating is best done when the ground is somewhat moist. Leave the soil/grass plugs on the lawn to break up and filter back down to the soil level. The plugs typically break down in seven to 14 days. Mark sprinkler heads and light fixtures in the lawn so they will not be damaged. If your lawn is thin, overseed after core aerating. Keep the seed moist for good germination.bull;Tim Johnson is director of horticulture at Chicago Botanic Garden.False20001329Paeonia False