Autumn is all about the garden

October 6, 2006 12:50 am

FALL IS THE perfect time for many beneficial lawn and landscaping activities--planting new trees and shrubs, maintaining existing plantings, controlling the broadleaf weeds in our lawns, and of course, fall lawn fertilization.

When you plant a new tree or shrub, the depth of the planting hole should let the top of the root ball be even with or slightly above the surrounding soil. In poorly drained soils you may want a shallower hole and have the top of the root ball 2 inches higher than the ground level, covering the root-ball surface with 2 inches of mulch. Planting holes should be 2 to 3 times wider than the root ball to encourage root growth out and away from the root ball.

Center the plant in the hole and backfill with the unamended soil that came from the hole. Don't amend the soil with peat moss or organic material, as this changes the soil composition and causes problems with water movement and root growth among the root ball, planting hole, and surrounding soil. A modest amount of fertilizer can be used at planting time. Too much can dry out the plant's roots.

Most of the trees and shrubs purchased at local garden centers will be in plastic containers or balled and burlapped--B&B. If the wrapping material is treated burlap or synthetic, it is not biodegradable. After placing B&B plants in the hole, remove any rope lacing and pinning nails, then cut away or drop any wrapping materials to the bottom of the hole. Remove the top 8-10 inches of a wire basket to prevent root girdling and prevent cultivating equipment from getting caught in the wire loops. Plants should be removed from plastic containers before they are placed in the planting hole.

Roots that circle around the root ball's exterior should be cut vertically along the root ball in a few places to prevent the girdling of its own root system. A well-disbursed root system helps keep plants anchored and aids in nutrient and water intake.

New plantings should get 2 or 3 inches of mulch, using either organic materials or inorganic materials such as river rocks. Keep mulch materials away from the trunks and stems. Landscape fabrics covered with 2 inches of mulch can be used for added weed control. Plastic sheeting blocks air and water exchange and shouldn't be used.

New plants will need to be watered after planting. Trees and shrubs need water throughout the fall and winter to help them become well-established and prevent damage from desiccation or drying out. Water plants on warm winter days when the ground is not frozen.

Fall is also a good time for tree and shrub maintenance. Rake up leaves and debris from around trees and shrubs that exhibited disease problems during the summer. The debris could otherwise reinfect these plants with the same disease, inoculum, next year. Prune out disease-damaged areas and remove that, as well. Don't put the debris in your compost pile.

You can fertilize established trees and shrubs in late fall through early spring. But doing it too early in the fall can promote a late-season growth spurt, and shoots or buds that are susceptible to frost and cold temperatures.

October to mid-November is also a good time to control broadleaf weeds. Dandelions, chickweed, plantains, mustards, wild onion, henbit and buttercup are examples of broadleaf weeds that can be controlled at this time of the year. These weeds are either perennials or winter annuals. Winter annuals germinate in the fall and over winter as seedlings, then flower and produce seeds in the spring, often dying out in the summer. These weeds are actively growing at this time the year and it is this fall-growth habit that allows for the uptake of herbicide. Herbicides commonly available to control these winter and perennial weeds include: 2,4-D, dicamba, mecoprop (MCPP), triclopyr, clopyralid, and dichlorprop. Best results are usually obtained when using these products in combinations and when the weeds are actively growing. Most garden centers carry these products in the combination forms. Always follow label directions when applying herbicides.

These herbicides, in granular or liquid form, can damage azaleas, dogwood and desirable ornamental plants, so use care when applying them.

Fall is the best time of year to fertilize cool-season lawns. An application of 1 pound of nitrogen per 1,000 square feet may be all that is practical. Many fertilizers are available as "weed-and-feed" combinations, but use the same precautions around desirable plants.