Fall Care and Clean-up of the Garden and Landscape

With the arrival of autumn colors comes the time to get the outside garden and landscape chores wrapped up. To avoid getting caught unprepared, plan tasks just ahead of nature’s time-table:

1 Valuable houseplants that have summered in the garden or patio rate immediate attention as the month of September approaches. Most are tropical in origin and will suffer a set-back when the night temperatures drop sharply at this time of year. Some may require grooming. A convenient way is to assemble them in an outdoor place where you can cut them back if necessary, inspect them for insect and diseases and repot any that have outgrown their containers.

Return them indoors in time for them to readjust to their indoor environment before the heat is turned on. Expect some leaf loss or the browning of leaf edges on some plant species. This simply indicates adjustment to lower light and humidity levels indoors.

2 Two plants which will require special care after their summer outdoors are the poinsettias and Christmas cactus. Both have similar requirements in that they need a 14 hour period of continuous darkness each day from October 1 until mid-December to set flower buds. Two methods to accomplish this are to either set the plants in a closet or place a cardboard box over them from 6 p.m. until 8 a.m. for the period listed above. At all other times, the plants should receive normal light exposure.

3 Keep pace with the weather by lifting or harvesting tender bulbs and corms that are desired for next season. These would include but not be limited to glads, dahlias and tuberous begonias. Many can be enjoyed right up until a good frost blackens their tops. Be sure to dig the bulbs carefully, retrieve any offsets that may have developed, and leave the foliage intact.

Place the bulbs in an airy, sheltered spot to dry for a two to three week period. Except for begonias, foliage and stems can be cut off with a sharp knife near but not at the point where they emerge from the bulb. Allow begonia stems to dry until they are brittle enough to break off from the bulbs.

The bulbs will overwinter well in a dark, cool place (45 to 50 degrees F.) when stored in vermiculite, peat moss, or similar material. It is also recommended to dust with a fungicide (Bordeaux mixture) and insecticide (Sevin dust) to curb disease and insect development in storage.

Except for daffodils, mice and other rodents consider bulbs of all kinds to be premium food, so store bulbs where these pests will not have access to them.

4 Finish planting spring flowering bulbs (ie. tulips, daffodils, flowering onions) and dormant, deciduous nursery stock while the soil remains manageable. If cankerworms were a problem the past summer, take action at this time to limit their damage next season. Fall banding with Tanglefoot should take place by mid-September to take care of the fall species of cankerworm moving into the canopy of trees. In most areas, however, the spring species of cankerworm is more destructive and warrants control in the early spring by banding with the same material in late March or early April.

5 Lawn care in the fall will yield maximum results the following growing season. Apply herbicides in September to control weed infestations. Aerate if the soil is compacted or if thatch is a problem and apply gypsum and fertilizer to improve soil conditions and provide nutrients for healthy turf growth The nitrogen should be mostly from water insoluble nitrogen (WIN) or controlled release nitrogen (CRN) to prevent excessive top growth. Continue mowing the lawn so that it is no higher than 1.5 to 2.0 inches going into the winter. A lawn should be only 1.5 inches tall where the snow tends to accumulate and snow mold or powdery mildew might be a problem. Most cool season lawns are best maintained at a 2- to 3-inch height during the growing season. As the month of October nears, the height can gradually be reduced to the overwintering heights.

If the grass ceases growth before all deciduous foliage has fallen, use the mower as a leaf mulcher or vacuum to keep the leaves from packing down and smothering the grass. Have the mower serviced and stored for winter to maximize efficiency and longevity of the machine.

6 Drain garden pools to avoid freeze damage. Store tropical (non-hardy) as well as hardy water lilies indoors. Roots and rhizomes of most kinds can be overwintered at about 50 degrees F. in a basement in moist sand that is not permitted to dry out. Many gardeners find it easier to purchase fresh propagules every spring.

7 Take preliminary steps to protect roses. Final winterizing is usually done in late October after a deep freeze, but tying the canes loosely beforehand will ease the job. For the final winterizing, cut the canes back to about 6 to 12 inches and mound the plants with fresh topsoil purchased earlier. Cover with cones or bushel baskets for complete protection. Many gardeners successfully overwinter their roses and other tender perennials by covering with bags of leaves collected in the autumn.

8 Install simple windbreaks to protect young, tender plantings from drying winter winds. Anything that encourages snow accumulation will help provide excellent protection against low temperature or wind desiccation. Where evergreens are exposed, spray with an anti-desiccant to provide protection from drying winds. Spray again in mid-winter during a thaw when the temperature will be above 40 degrees F. for a few hours.

9 Protect young apple, maple and other tree species from rodent damage. Wrap tree trunks with hardware cloth (� inch openings) up to the expected snow-line to provide the necessary protection. Plant material that has developed a thickened or corky bark is usually not vulnerable to damage of this sort.

10 After a heavy frost, remove all blackened plants such as zinnias, petunias, marigolds, etc. Remove and destroy plant stems on any perennials which may have had diseased foliage (ie. peonies and lilies). Good sanitation now will result in fewer problems next spring.

11 If there is time, turn the soil over in vegetable and flower gardens. Litter-free areas in the garden or under fruit trees will help eliminate many disease and insect problems the following season. Open spaces of fallow, weed-free soil are more attractive in winter and will make the soil ready for planting early next spring.

If the soil is particularly heavy, the addition of gypsum at 40 pounds per 1,000 square feet will help to soften the soil next spring. Thorough incorporation of generous amounts of organic matter such as compost or peat moss is also very beneficial.

Finally, to stretch out flowering a couple more weeks in the autumn, covering plants with plastic or cloth sheets, boxes or newspaper tents will provide protection against the initial frosts. Frequently, unprotected plants damaged by light frosts can be given an extension of useful beauty by hosing them with water before the sun rises.

Post Resource: http://www.ag.ndsu.edu/pubs/plantsci/hortcrop/h1033w.htm

Posted in Seasonal Information.