September in the garden: Make notes on the changes you’d like in your garden next year

Now is the time to document any changes you have thought about making to your garden as you watched the season go by. It is easy to forget these observations over late fall and winter. Good garden notes will make you more efficient and your garden better looking.

General garden careInstall steppingstones in garden beds where you frequently need to walk. There is a wide variety of materials to choose from for steppingstones. Pick one that complements your house, your plant materials and the pathways and other hardscape elements in your yard. Dig a shallow bed for each steppingstone and use torpedo sand (sold in tubular bags at the home center) to level it and set it into place. The sand will help to keep the stones from shifting when they are walked upon.Install pegboard on the walls of your garage to hang garden tools. They will take up less space hanging on the wall and will be easier to reach. It also is a good practice to clean tools before putting them away. Remember to sharpen your tools regularly to make your gardening chores easier.Powdery mildew, a disease that causes a grayish, powdery film on leaves, often appears in the late summer when the weather is warm and humid. Common plants that can get powdery mildew include lilac, phlox, bee balm, zinnia and nannyberry viburnum. Fungicides can help control powdery mildew if they are applied before the infection becomes severe, but it is generally not worth applying any controls this late in the season. Other options include moving the infected plants to an area of the garden that has better air circulation or replacing them with more mildew-resistant varieties. Plants that prefer acid soil such as rhododendrons and azaleas can benefit from an application of granular sulfur in fall. Wear latex or vinyl gloves to avoid contact with the sulfur and keep the dust out of your eyes. Apply the sulfur to the soil and gently scratch it in. Sulfur works slowly and you may need to repeat the application from year to year. Spring and fall applications should work well. If you have deer in your neighborhood, it is time to protect the trunks of smooth-barked trees such as young maples from rubbing. Deer often use smooth-barked trees to rub the velvet off their antlers in late summer and early fall. This can damage the bark and even kill a tree if the damage goes all the way around the trunk. To protect it, wrap the trunk with tree wrap, chicken wire, hardware cloth or plastic snow fencing to a height of 5 feet. Hardware cloth will provide the best protection. Tree wrap offers little protection and likely will not be adequate if your garden is near a green space such as a forest preserve. Remove any protection from the trunk in early spring. You may be seeing foliar diseases on your crabapples after a summer that has brought a lot of rain and humidity. Some crabapples 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 applied in spring. To increase the vigor of the trees, provide supplemental water as needed and fertilize in spring. PlantingTry to buy mums and asters when their flower buds are just beginning to open, not when they are in full bloom. The color will last longer in your garden. Generally mums and asters will last for four to six weeks depending on the weather. Season-extender mums can keep color going through October and sometimes later. Sometimes, however, you should plant fall flowers in full bloom. If you are planting mums in a shady site then it is best to wait until the flowers are open before planting. Pansies will typically not develop much in the autumn season, so it is best to buy large plants that are in full flower and plant them close together. Fall is a great time to plant and transplant trees and shrubs. Fall conditions, which include warm soil, moderate air temperatures and rain, help plants re-establish their root systems. In general, trees and shrubs do not need to be pruned when they are transplanted. 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. Also water other evergreens planted over the last three years; they will be more prone to winter burn if they go into winter dry. Mulch is important for fall plantings. Spread it in an even layer 2 to 3 inches deep, keeping it away from the base of the plants. BulbsIt is time to order spring-flowering bulbs. As you plan your bulb planting, choose a site with well-drained soil. Any area in the garden that remains wet for long periods or has standing water for any length of time is unsuitable for bulbs. They prefer moisture in spring and fall and drought in summer. Leucojum aestivum, summer snowflake, does have some tolerance to moist conditions.Most bulbs prefer full sun. When planted beneath a high branching tree, spring bulbs will often flower before the tree leafs out, when they have only light shade to contend with. Most animals are reluctant to eat alliums, or ornamental onions. These bulbs, usually with globe- or egg-shaped blooms, come in many varieties. Try the popular June-blooming Allium #145;Globemaster#146;, which has a 10-inch pinkish-purple flower that lasts up to a month atop a 2- to 3-foot stem. The drumstick onion, Allium sphaerocephalon, has reliable burgundy blossoms about 1 inch wide. Allium moly, lily leek, is a small species that grows 10 to 14 inches tall with yellow flowers. These are just a few of the many alliums that succeed with little effort in Midwest gardens if you plant them this fall. Daffodils are also easy to grow and are resistant to animal browsing, while tulips and crocuses are often eaten.LawnsFertilize your lawn in early September to improve the color and vigor of grass. If you only fertilize your lawn once a year, this is the best time to do it. Nitrogen is the nutrient lawns need most, although too much nitrogen can cause excessive top growth and disease problems. In most cases a rate of 1 pound of nitrogen per 1,000 square feet of lawn is sufficient. 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 in fertilizer for the sake of water quality, as it can fuel algae growth in lakes and streams. 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. Mark sprinkler heads and light fixtures in the lawn before work begins so they will not be damaged. Leave the plugs of soil and grass on the lawn to break up and filter back down to the soil level. The plugs typically break down in seven to 14 days. If your lawn is thin, overseed after core-aerating. Keep the seed moist for good germination. Most residential lawns will only need to be aerated once a year in fall or spring. Heavily-used lawns will benefit from being aerated twice a year.Schedule a time next month to have your sprinkler system drained for winter. Water left in the system can freeze and crack sprinkler heads and pipes. Compressed air often is used to blow water out of the system.If you spray to control weeds in the fall, be aware of the weather. Herbicides are most effective when temperatures are still consistently above 55 degrees and weeds are actively growing. ŸTim Johnson is director of horticulture at Chicago Botanic Garden (chicagobotanic.org). 15002258Phlox can get a grayish film on it this time of year. If caught early, powdery mildew can be treated with fungicides. 15002241If your zinnias attract the grayish film of powdery mildew, consider moving the plants to a place with more circulation.