It wasn't necessary for the snow to melt to see the damage done by the cold to many ornamental and fruit trees. Serious damage has occurred to most of the peach trees and other stone fruits. Delay pruning these trees until you can determine which buds are still alive. Be patient, there is still time to prune.
Dead buds on woody plants fail to swell and bloom normally. Even those buds that bloom normally are not guaranteed to produce fruit, but early pruning may remove desirable plant tissue and any remaining fruit buds.Weather damage dictates the need for conservative pruning and conservative fertilization this year. Over-fertilization in years when fruit is not on the tree stimulates excessive vegetation growth.
After determining the dead branches, remove them. Don't allow dead, damaged or broken tissue to remain in the tree. These branches become a breeding site for a serious fungal disease called cytospora.
Cytospora affects many different woody plants, but fruit trees are among the most severely affected. In addition to the winter kill problems, fruit trees are pruned frequently, and open wounds allow the fungi to infect the tree.
Cytospora attacks trees that are weakened or stressed by any problem, including winterkill. The disease is not easily controlled. Sprays are not generally effective. The best disease-control strategy is to improve the tree's health. Do this by fertilizing trees with adequate nitrogen fertilizer. Avoid additional stress on the trees from insects, diseases and mechanical damage, including weed eaters and lawn mowers.
Infested branches should be removed and destroyed to prevent the disease from spreading. The disease is recognized by orange- or reddish-colored bark covered with black dots or pimple-like structures.
Euonymus, laurels, boxwood and other broad-leafed evergreens suffered greatly from the low temperatures. One pleasant surprise from the melting snow is the presence of healthy, undamaged tissue at the base of many of these plants. Fortunately, the snow covering the base of the plants prevented them from being killed outright. In many cases they will die back to the original snow line, but will regrow from the base.
Delay pruning until you determine the tissue that will regrow and produce healthy shoots. Don't worry about removing brown leaves. If the leaves are dead they will fall off soon enough or be removed in the normal pruning process. Over-pruning early in the season results in poor growth and weaker plants later in the season.
The full extent of damage to many trees will not be known until later in the growing season or possibly for several years. Freeze damage is difficult to assess and problems become more severe from exposure to low temperatures in subsequent years. Fertilize ornamental trees and shrubs with nitrogen fertilizer to promote healthy green growth this spring.
It is no surprise that when the snow melts it brings on gardening fever. Don't be in too big a hurry to work your soil. Check it by taking a handful of soil from underneath the soil surface. Form a ball of that soil and toss it gently in the air. If the ball crumbles easily, it's OK to go ahead and work that area of the garden. If it holds together, delay tilling the soil. Tilling soils that are too wet destroys the soil structure and makes them unworkable.
- SPRING 1991 garden workshops offered by USU Extension Service are held at the County Government Center, 2001 S. State, Room S1007. Classes are held from 2-4 p.m. or 7-9 p.m.
- Tuesday, March 12, "Tree Fruits": Proper selection, planting, care and pruning. No charge.
- Tuesday, March 19, "Small Fruits": Growing raspberries, strawberries and grapes in the home garden. No charge.
- Outdoor pruning demonstration will be held on Saturday, March 9, at 11 a.m. or 1 p.m., A.B. Culley residence, 3705 S. 7200 West, Magna. No charge.