Rick Durham, Consumer Horticulture Extension Specialist, Department of Horticulture, University of Kentucky.

Fall is the time to clean things up in the garden and landscape.

Many diseases and insects will overwinter in the garden on plant material or leaf litter. Therefore, it is best to clean up the garden and landscape once growth has ceased for the season.

• After the first hard freeze, remove non-hardy annuals and cut back perennials to near ground level. Use care when removing perennials since the stems are attached to the crown of the plant where next year's growth will originate. Thus pulling up such material may damage the crown so it is better to cut the plants off at their base. Annuals on the other hand can be removed by pulling or cutting since they are not expected to return from underground structures. The removed plant material can be placed in the compost bin.
• Also clean up around fruit trees by raking leaves and removing dried fruit. This will help control several diseases and insects. For example, apple scab, a fungal disease which infects many apple varieties and certain crab apples, spends the winter in dead infected leaves on the ground. The warm moist weather of spring triggers the fungus to resume growth and release spores that will infect new growth on the tree. Therefore, raking up dead leaves from under apple trees in the fall is one way to reduce the severity of disease next spring. The disease may not be completely controlled in this manner, but good sanitation practices such as this are an important part in any disease control strategy.
• Many insects can also be found in dead leaves in and around the garden and landscape. Pests such as European corn borer, squash vine borer, and Mexican bean beetle, to name a few, are able to overwinter in the garden. These insects often make their home in dead leaves and plant material which offers them some protection from the elements. Getting rid of those dead tomato vines, bean bushes, and squash vines and fruit will lessen the chance that these pests will be able to overwinter in the garden and so will lessen the incidence of pest problems next spring.

With cooler weather and many plants going dormant for winter, there is definitely a reduced need for watering. However, this doesn't mean that the hose should be rolled up and stored in the garage-at least not quite yet. Trees, shrubs, and evergreens need to enter winter with adequate moisture around their root system. This helps protect the root system from freezing, and the entire plant from drying out during winter. Once the soil freezes, it does not adsorb additional water, so it is important to make sure the soil is most prior to freezing. This is especially true of evergreens. Most water loss by a plant is through its leaves. Therefore deciduous plants will use/lose very little water during winter but still need to be protected from drying out by having some water available to the root system. Evergreens, on the other hand, will continue to lose some water from their leaves year round. The cold, dry climate of winter can be especially damaging to these plants. So it is particularly important the ensure that evergreens have adequate soil moisture during fall and winter. Continue watering as long as the soil hasn't frozen and rainfall is less than adequate to keep the soil moist.
 

Fall/winter is the time to fertilize woody plants.

Late fall is the best time to apply fertilizer to trees and shrubs. Most will only require nitrogen. A general rule of thumb is to apply 2-3 pounds of nitrogen for every 1,000 square feet of root area. That's not 2-3 pounds of fertilizer, it's 2-3 pounds of nitrogen. For example, the analysis for ammonium nitrate is 33-0-0. The first number always represents the percentage of nitrogen in the fertilizer. So ammonium nitrate is 33% nitrogen. To apply 2-3 pounds of nitrogen, one would need to apply 6-9 pounds of ammonium nitrate. If this can be split into two or three applications by applying part of the fertilizer in October, some in November, and the remainder in December. How do you calculate the size of the plants root area? Consider that most woody plants will have a root area that extends 2-3 times the diameter of the to trees canopy or limbs. Measure from the trunk to the outer edge of the tree's canopy, multiply that number by 2 to get the radius of the trees root area. Then plug this number into the formula for calculating the are of a circle, A = pi times the square of the radius.
 

Fall mulching.

Fall is an excellent time to apply mulch to the landscape. Often municipalities will offer free mulch made from composted yard waste collected over the past summer. Mulch is an important addition to any landscape. Not only does mulch make the landscape look better, but mulch also has many other beneficial characteristics including reducing weed growth, conserving moisture, moderating soil temperatures in summer and winter, and reducing erosion and soil splashing. Mulches are categorized into two basic groups depending on their makeup.

• Organic mulches include such material as bark, wood chips, leaves, grass clippings, pine needles, compost, and newspaper. Organic mulches decompose over time and the organic matter becomes incorporated into the soil. This process is mostly desirable since organic matter tends to improve aeration and water holding capacity of the soil, and also promotes the activity of beneficial soil organisms including earthworms, bacteria, and fungi. The activity of these organisms release nutrients that are needed by plants. The fact that organic mulches breakdown over time means that new mulch will need to be applied periodically depending on what type of mulch is being used.
• Inorganic mulches include such material as gravel, plastic, landscape fabrics, and rubber pellets made from recycled tires. Inorganic mulches are relatively inert so they do not break down over time. Plastics and certain landscape fabrics will break down in sunlight. Often a layer of organic mulch is placed over these materials to reduce sunlight exposure. This both prolongs their life in the landscape and improves the attractiveness of the material. Consider the long-term implications when applying an inorganic mulch. Gravel is impossible to separate from the soil once mixed and may become a nuisance on paved walkways and in adjacent turf areas. Chipped limestone will make soils more alkaline and should not be used.
• Mulches are usually applied to a depth of about 2 to 2 and a half inches and should not be applied deeper than about 4 inches. They are most frequently applied in late fall after the soil has frozen. A layer of mulch helps prevent freeze/thaw cycles in the winter. Newly planted plants are especially susceptible to fluctuations in soil temperatures and may even be heaved out of the soil during severe freezing and thawing.