There are a number of things that a gardener should do to prepare plants for the upcoming growing season. April is an ideal time accomplish all of the important cultural activities that are required to produce delicious fruit later in the season.
Generally we recommend that mature bearing fruit trees should be pruned in the spring each year. Moderate to light pruning is essential. If extensive pruning is necessary, it is best to be done over a 2 to 3 year period. There should be a balance between vegetative growth and fruiting within a tree. Severe pruning will cause excessive vegetative growth, reducing flowing and fruiting for several years. General rules for pruning tree fruit include the following guidelines.
- Remove broken, diseased, or insect-infested branches.
- Retain branches that are horizontal or have a 45 degree angle with the trunk. Remove branches that form a sharp upright angle with the trunk and weak branches that are drooping.
- If light does not penetrate into the center of the tree, thin out the interior by removing whole branches or branch portions of a larger limb.
- Stimulate growth where needed by cutting to shoots and buds that are pointing upward. Conversely, if pruning is required on very vigorous trees, prune to weak shoots or buds that are pointing in a downward direction.
Cropping of small fruit such as blueberries, grapes, currents and gooseberries is usually regulated by pruning, so more vigorous pruning in the spring is often appropriate. Blueberries are generally pruned by removing 2 to 3 whole canes per year, leaving only canes 6-years-old and younger. Grapes are pruned by selecting the 4 to 6 moderately-growing canes and then distributing 40 to 60 buds on these canes on moderately vigorous vines. All other canes are removed, with the exception of a few that are retained and cut to one bud to provide canes next year.
We recommend application of fertilizer in April so that the nutrients will be in the root zone when growth resumes in the May. When nutrient deficiencies occur, when additional growth is desired, or when excessive spring rain leaches nutrients early, a second application can be made at the end of May. With tree fruit and woody small fruit, fertilizing after the middle of June is not recommended because it may encourage growth too late in the season. If this occurs, new shoots may not harden off properly and become susceptible to winter injury.
Fertilizing with organic or slow release fertilizers is often less satisfactory on tree fruit and woody small fruit. Nutrients and especially nitrogen are made available continuously throughout the season, which may encourage late growth and increase the possibility of winter injury. The simplest solution is to apply a water soluble fertilizer such as 10-10-10. This fertilizer is readily available at garden centers and it can be used on all fruit. A 10-10-10 fertilizer contains 10% each of nitrogen, phosphorus, and potassium. Specific recommendations for the amount to apply are difficult because of the numerous factors that influence nutrient availability but a general guideline is provided in Table 1. Fertilizer should be spread evenly over the top of the ground under the tree or plant and out as far as the branches spread. Fertilizer should not be applied to strawberries in the spring of fruiting years. Fruit taste will be substantially diminished, strawberries will be softer, and the resulting vigorous vegetative growth will encourage the development of fruit rots.
Table 1. Fertilizer recommendations for selected fruit crops
|Fruit||Amount of 10-10-10 (Cups/Year of age)||Max. Amount to Apply Per Year|
Planting Fruit Trees and Small Fruit
The best time to plant trees and small fruit plants is as early in the spring as the ground can be appropriately worked. Usually this is early to mid April. Care should be taken not to work the soil too early when it is very wet since soil compaction is likely. Work the soil and apply soil amendments before planting. Early planting allows for root development and growth into the surrounding soil before warm weather creates a large demand by the top for water.
Remove Mulch from Strawberries
Strawberries are mulched in the fall to protect them from cold injury during the winter. Mulch should be removed now to allow leaf development. In the past, gardeners have left mulch on in the spring in the hopes of delaying bloom, thus reducing the chance of frost damage. Recent research has shown that delaying removal of mulch will reduce flowering. Mulch should be retained around the individual plant so that developing strawberries later in the spring will not become dirty and the chance of rot will be reduced. Excess mulch should be placed in the row middles to suppress weeds and make harvesting fruit more pleasant.
Repairing Trellis and Putting up Supports
April is an excellent time to install trellises on both tree fruit and small fruit. This is also an appropriate time to make repairs to existing structures. Shoots will not be growing at this time, so installation and repair around plants will result in minimal damage to the plants.