November Gardening Tips

Tips for New Hampshire gardeners in November

Protect trees and shrubs from vole damage over the winter by placing cylindrical guards made of ¼” galvanized hardware cloth around their bases.

Voles are compact rodents with stocky bodies and short legs and tails. In the spring and summer they feed on grasses, weeds and fruits, but once there is snow on the ground they can cause a tremendous amount of damage by feeding on roots and bark. Extensive feeding can girdle the stems of trees and shrubs and kill them. Young trees are especially vulnerable, although when vole populations are high, voles will feed on any age tree. Plants voles are likely to damage include: apple, blueberry, peach, pear, cherry, dogwood, Japanese maple and juniper.

Wait to prune trees and shrubs until spring.

In the fall, plants are in the process of going dormant and do not produce very much new growth until the spring. Plants that are pruned in the fall are at greater risk of winter injury, because new wounds are more susceptible to extreme cold. Avoid dieback at pruning sites by waiting to prune until late winter or early spring, just before plants enter a rapid growth phase. When trees are pruned in the late dormant season new wounds are only exposed for a short time before active growth starts and healing can begin.

It’s still not too late to plant a few more bulbs.

Many spring blooming bulbs, and even garlic, can be successfully planted up until the ground freezes. Planting depth and spacing depends largely on the type of bulb you are growing. The packaging that bulbs come in usually includes planting instructions, but in the absence of those, plant bulbs two to three times deeper than their diameter and at least three inches apart. Bulbs should always be planted with their pointed end up and the root end facing downward. If you are not sure which end is which, it is better to plant bulbs on their sides rather than upside down.

Check houseplants for pest issues.

It is very possible that a plant that spent the summer outside picked up a few insect pests or developed a disease issue during that time. Isolate and treat infested/infected plants before issues spread to others. Remember that using a pesticide should always be a last resort. Many pest issues can be resolved by hand-picking insects or diseased leaves from plants.

Apply limestone to the lawn or garden at the rate recommended by a soil test.

Lime increases the soil pH, which is a measure of acidity or alkalinity. The optimum pH level for most lawns and gardens is between 6.0 to 6.8. Keep in mind that lime should not be applied unless a soil test indicates that it is needed. Too much lime can be just as harmful as too little, causing potential nutrient deficiencies. It can take as long as six months for lime to fully raise the soil pH, so a fall application will help you prepare your garden for the next growing season. Rain, snow, and frost heaving help incorporate limestone into the soil, gradually raise the pH over the winter.

Protect evergreen trees and shrubs from winter damage.

Broadleaf evergreens, such as Rhododendrons, are particularly susceptible to drying out in the winter months, though needled evergreens can sustain damage as well. Symptoms of winter burn include brown dead leaves and needles that appear in late winter and spring. Because they do not shed their leaves, evergreens lose water over the winter in a process called transpiration. When the ground freezes, evergreens sometimes lose water faster than it is taken up, and their leaves begin to dry out. Desiccation can be mitigated by erecting windbreaks made from burlap or canvas to attached frames around plants on the side facing prevailing winds, or plants can be entirely wrapped with burlap if they are small and compact. Never use black plastic, as it causes extreme temperature fluctuations that can damage plant tissues. 

Keep deer out of the garden by installing fencing around plants susceptible to deer, or applying repellents.

Deer often show preference for holly, arborvitae, rhododendron, yew and apple. Excluding deer from these plants with fencing is the most effective strategy. If you have just one plant that the deer seem to find irresistible, you may find that it is more economical to build a wire cage around that individual tree or shrub. Since deer usually only browse on woody plants during the winter months, you may only need to have the cage in place during that season. Repellents are the next best way of dealing with deer. Repellents that trigger a fear response are often most effective, and generally contain ingredients such as putrescent egg solids, predator urine, or slaughterhouse wastes. Wrapping certain plants, such as arborvitae, with burlap may also limit deer browsing.