Pruning season In South Texas, it's the weather not the date

January 27, 2005
by Donna Roberts, Victoria County Master Gardener

Every February, the day after Valentine's Day, I shudder as I prune my dead-looking perennials back to only a few inches from the ground. I always worry that somehow I am destroying all of my plants that attract birds and shower me with color throughout the growing season. I am still working on getting over that feeling because I know that pruning is one of the most beneficial of all gardening activities. I'm always amazed when new buds pop out from what once was a dead-looking branch.

No matter where one lives, each gardening season can be characterized as having three parts, early, mid and late. Even in South Texas where frost is infrequent, we still have extreme heat, drought and flooding, and there is inevitably a division and change of seasons - a time to prune and a time not to prune. Plant growth cycles are tied to day length, whether the days are increasing or decreasing in length and whether the average temperature is ascending or descending.

Good pruning also brings rewards in the form of bigger and better plants, higher quality fruit, and well-shaped trees and hedges. Pruning is not only about removing unwanted shoots but also about stimulating the growth of others. It does not necessarily reduce the height of a plant unless repeated regularly because previously dormant buds will simply replace the removed shoots and continue upward growth. It will produce a bushier tree or shrub, which is why removing the main growing tip is important in formative pruning for young trees.

Let's start by talking about objectives in proper pruning. Following is a list of suggestions for when you begin:

Cut out dead and diseased wood - wood that has started to die back as a result of frost damage, previous pruning wounds or just disease infection. Cut back to healthy wood, just above a bud

Remove branches with narrow attachments - less than 30 degrees, as they will have a weak joint and split off later in life. Leave branches with wide angles - 60 to 70 degrees

Eliminate badly crossed branches - cutting out branches that cross and rub together will improve the appearance of the plant and reduce the risk of infections caused by the friction damage

Prune out all-green shoots on variegated shrubs - these shoots are more vigorous and in time may dominate the plant

Eliminate multiple shoots growing from a wounded tree - these cause overcrowding if allowed to remain - cut them off at the base, flush with the branch or trunk

Remove basal shoots - a.k.a. suckers
Cut out winter damage - shrubs, especially evergreens that are not totally hardy, may be damaged by a very severe winter - it's not just frost that can cause the damage, but also cold winds are a culprit.
There are several techniques for pruning including:

Clipping to shape - as with shrubs

Reducing new growth by half - this helps in the plant not becoming straggly and bare at the base

Pruning by deadheading - this makes the plants look tidier, keeps them low and compact and improves flowering

Shortening sideshoots - this stimulates more sideshoots and therefore more flowers by reducing new shoots by two-thirds after flowering

Cutting out one stem in three - this helps shrubs remain compact and vigorous with plenty of new growth - it also prevents shrubs from becoming too woody and tangled with age

Cutting back to the ground - I usually do this with my hibiscus and firecracker plants in mid-February as it makes them fuller and more colorful.

Pruning has obvious benefits to help shape a plant, not only by removal of a branch or shoot but also by causing new shoots to grow from dormant buds. To reduce the risk of infection from fungi and bacteria, the right cut is also necessary. One should make a sloping cut in the same direction as the new bud. Avoid cutting so close to the bud that you risk damaging it, but do not leave a long stump as this is more likely to become infected.

Nicking and notching are two words used by some gardeners interchangeably; others use nicking to imply a cut below the bud and notching for a cut above the bud. Nicking a small crescent or triangle of bark below a dormant bud will inhibit growth. These methods are mostly used for fruit trees, to promote or inhibit the development of specific buds. Late spring is an appropriate time for this kind of growth control. Notching a small crescent or triangle of bark above a dormant bud tends to stimulate it into growth.

If you prune in winter when the plant is dormant, little internal activity will be taking place, but regrowth will be extensive when the plant does start to grow again. Pruning in spring and early summer often produces thin growth with narrow angles between old and new shoots. Pruning in mid or late summer has the least effect on new growth. There is a risk that shoots produced late will be less able to resist cold damage, so it is best to avoid pruning this time of year for plants of borderline hardiness. In our climate, it is generally best to not prune extensively until after mid February when our chance of frost is very low. You should not try to prune by specific dates, but according to the progress of the seasons and their effect on plant growth in a particular year. Therefore if you read advice from other parts of the country on pruning, be sure to know when to prune in South Texas. For example, if advice were to prune a certain plant in late spring, after flowering, in most places in a normal year this would be in May. However, in very mild areas such as in South Texas, flowering could start as early as March. You may also have to delay pruning if spring is very late one year. Recently, with our unusual weather pattern in Victoria, adjustments in pruning will be likely. A guide to go by if in doubt is as follows:

Early spring - March

Mid-spring - April

Late spring - May

Early summer - June

Mid summer - July

Late summer - August

Early autumn - September

Mid autumn - October

Late autumn - November

Early winter - December

Mid-winter - January

Late winter - February.

This is obviously just a guide so it's best to always be prepared to make adjustments to suit local conditions.

I know that after our recent white Christmas you must have some pretty unattractive plants in your beds and gardens - I know I do. However, instead of going out now and tidying up, have a little more patience and wait until mid February when it will hopefully be safe to start your pruning. As I look out my windows at the black limbs and dead looking plants, I can only think back at what a beautiful sight it was on Christmas Eve and Christmas morning in South Texas in 2004 - I think I can live with the sight until February.