Tree and Shrub Spring Update

Dormant Oil
Spring Pre-Emergent for your trees and shrubs.

When controlling weeds in lawns, the pre-emergent herbicide used in spring is the most effective way to control weeds. If they never start growing in the lawn, you do not have to worry about them multiplying. The same thing goes for insects on your trees and shrubs.

Think of applying dormant oil to your plants as being like a pre-emergent for insects. In most cases, insects mature very quickly and are old enough for reproduction in a short amount of time. Adults lay eggs on and inside the leaves and stems in the fall. These eggs sit over the winter, and then begin hatching as the temperatures increase in the spring. Leaf miners are one of the biggest problems early in the spring. Small flies lay eggs on the undersides of leaves. In the spring these eggs hatch and the larval insect burrows into the flesh of the leaf, eating its way through and causing damage.

Dormant oil, or Horticultural oil, will suffocate and kill the over-wintering eggs from last year's adult insects. This product is often applied in conjunction with a contact insecticide in order to control any newly hatched eggs or larvae that might already be feeding on your plants in the early spring. February and March are the best times to apply dormant oil, and this is the time of year we apply our spring dormant oil treatment for our tree and shrub customers.

Dealing With Freeze Damage
Facts and corrective actions

It is not uncommon for spring temperatures in the Southeast to be 70 degrees for several days, and then suddenly drop to below freezing. When the temperatures rise, many plants will begin to bud with new spring growth. Unfortunately this new growth is often killed by frosts that come afterwards.

New plant growth contains a good amount of water. When the temperatures freeze, the water held in the new growth freezes, and this causes irreparable damage to the cells of the new growth. Plant material that is freeze damaged will curl and turn dark brown or black in color. Not only can the new leaves be damaged, but the stems of the new material can become dark and brittle if affected by freeze damage.

There are several protective measures that can be taken to help avoid freeze damage to your plants. Unfortunately you cannot go outside and tell them not to grow; they do not listen too well. You can, however, use items such as frost cloth, burlap, old sheets, plastic drop cloths, and cardboard boxes to help protect your plants from a coming freeze. Exposure to wind chill is what causes the most damage to plants, and these items will help keep the wind off your plant material. It is VERY IMPORTANT that you remove this protective material the next day.

You may have plant material that is simply to large or too tall to effectively cover, and damage will most likely occur. This is not as bad as it seems. Freeze damage normally occurs on new growth, and this damaged material can simply be pruned off later in the spring. DO NOT prune immediately, however. Leave the damaged material on your plants until there is no more reasonable chance for freezing weather. The dead material at the tips will prevent the plant from producing more new premature growth, and it will also insulate the rest of the plant.

In some severe cases you may find the bark on some of the newer, smaller limbs will be split by the freezing temperatures. This can cause the material on the entire limb to die. Just as with the damaged leaf and stem material, you should wait to prune it out until after there is no more reasonable chance of freezing weather.