BY Lori Murray, , Texas Superstar Specialist
EDITOR’S NOTE: Cameron County Horticulture Agent Jennifer Herrera gave me a file of articles on a variety of subjects created by a one-time Master Gardener Horticultural Education Committee that no longer exists. In looking over the files I discovered several that I think will be useful, so I have edited them and will run them from time to time (sometimes even without pictures!) as they seem appropriate.
Lori Murray, Cameron County Master Gardener, Texas Superstar Specialist.
Shrub pruning may be necessary for a variety of reasons. The method and timing can vary depending on the species, age, and condition of the plant. The main reasons for pruning, aside from wanting to create or maintain a rigid, formal appearance are:
1. to remove broken branches which resulted during planting.
2. to remove dead branches, or to remove areas infested with insects or disease.
3. to correct or improve the shape; for example, a branch may spoil the general balance of the plant, or may grow into other plants or a pathway.
4. to improve ventilation and light: i.e. a branch may cross other branches on the same plant and shut out light and air to the center of the plant.
NOTE: It is important when planning your landscape design to consider a shrub’s height and width when fully grown. A large growing shrub in a small space is a constant pruning chore.
WHAT AND HOW
Remember the purpose of pruning, except for diseased or damaged branches, is to control growth, and this process should occur gradually throughout the year as opposed to severe pruning once a year.
Regular pruning results in more air and light penetrating the plant, and results in leafy growth from the older wood, producing a fuller, healthier, more attractive plant.
REMEMBER when pruning to make all cuts at the base of a branch, i.e. at the branching point, leaving only a cut flush with the remaining branch or a stub of less than 1/4 inch (6 mm).
To achieve an irregular or informal ‘natural’ looking shrub or hedge which fits into every landscape, the cutting back of individual large, medium, and small branches, creates a soft appearance.
NOTE: Shearing off the outermost few inches of growth creates a hard, formal outline of a trimmed hedge.
Pruning to achieve a ‘natural’ look should be carried out in three stages:
1. Removal of large branches should be done below the center near the base of the shrub, the object being to shorten the overall height of the plant and to open the center for light penetration and air movement.
Only one or two such cuts are necessary. The branches removed are from parts of the shrub which are the most crowded and where their loss will be the least noticed. They should be removed if they are unattractive, damaged or diseased. Care should be given to cutting large branches because their removal will dramatically alter the look of the shrub.
2. Removal of medium sized branches should be done after the removal of larger ones, to continue the opening of the shrub for air and light penetration and to create uniformity in shrub density. Care should be exercised to avoid drastic pruning.
The overall look of the plant must be taken into account during the pruning progress. Removing branches over the entire shrub one by one and stepping back from the plant to assess the overall effect of balance and density is the best procedure.
3. Removal of some of the growing tips is the final pruning stage.
This pruning removes only 1 to 3 inches (2 to 8 cm) of growth and is used to continue the opening of the shrub. The overall look of the plant will be a soft, feathery appearance resulting from the removal of growing tips here and there over the entire shrub.
When to prune
The best time for pruning depends upon the shrub. When shrubs have lost their leaves due to winter or drought, prune them after the danger of frost has passed.
A leafless shrub allows for the assessment of the overall shape and possible health problems, as well as ease in seeing where cuts are to be made. Otherwise, light pruning to control growth throughout the year is acceptable.
If you have pruning questions about your particular shrubs contact your Certified Texas Nursery Professional.
(Source: Native Shrubs of the Lower Rio Grande Valley, Texas, Landscape Uses and Identification. Native Plant Project, Edinburg, TX 78540).
Cameron County Horticultural Education Committee, Cameron County Extension Service