Proper pruning of ornamental plants


Are you as tired of making New Year’s resolutions and then breaking them as I am? My resolutions were actually very simple… get my garage cleaned out, get in shape, and to keep off the weight I lost last year. We are only in the second week of January and my desk looks like it became the national storage area for the world’s supply of useless and discarded paperwork. I was taking out the garbage the other day and actually had to stop and rest on the way to the dumpster (I made it fine the first 50 feet but it was the last 50 feet that really got to me. I have also gained five or six pounds thanks to all the holiday food we fixed at the house – we are a family of four but cooked enough for twenty just in case I guess. This makes me a perfect 0 for 3 on my resolutions, I hope you are doing better.

I got a real wake-up call just the other day while I was of all things getting my New Year’s hair cut. It was a real eye opener for me to see all the gray hair falling onto the black apron that was draped over me; I always remembered my hair as dark brown so I pulled a few old photos just to be sure. Well, if my hair was a plant, I’d know just what to do about it! A little pruning would certainly be in order.

The health and beauty of most ornamental plants depend to a certain degree on proper pruning. Pruning is something that should never ever be done simply at random. You should always keep in mind the natural form of your plant before you make the first cut. Cultural pruning is done to encourage and promote fruit and flower production, promote the health of your plant and to a small degree control the size and shape of the plant. I have always maintained though if you have to constantly prune a plant to keep its size under control, the plant is the wrong choice for its location.

There are times that pruning is actually urgent and must be performed immediately. Such is the case when you are removing limbs that create a hazard to your home or to someone’s safety and to remove diseased or broken limbs that can endanger the health of your plant. Other than these cases, timing is everything with pruning.

Here is a general rule that holds true for most plants. If it blooms before May 1 prune it immediately after flowering (azaleas for example) and if it blooms after May 1 prune it during the late winter or early spring (crape myrtles for example).

It is critical to remember the number one rule of pruning and that is pruning is localized in effect. What that means is that wherever you make a cut is where the new growth will sprout. I personally think that one of the worst mistakes that most pruners make is shearing our plants, the old “buzz cut” as I call it. I have seen this done to everything from crapes to boxwoods to forsythia and even large trees. Actually what this does is to promote a canopy of foliage at the top of the plant while its interior becomes barren of leaves and flowers. Most plants done this way will become thin and unattractive. Try making deep cuts into the interior of the plant and staggering the height a little bit.  This takes longer but the added sunlight that reaches the interior of the plant will give you a fuller more natural appearing plant. This works great with such plants as forsythia, hollies, boxwoods, and even azaleas as well as many others. Pruning deep inside the canopy can also reduce the need to re-prune the plant as often. Trust me, the additional time is worth it. Here is another little trick, if you like a very formal appearance, such as a boxwood hedge row, leave the top of the hedge ever so slightly narrower than the bottom. This allows sunlight to reach the whole plant and again will make the hedge fuller from top to bottom. Don’t just shear it straight down the side.

People often ask me what to do about those plants that have gotten totally out of control size wise or else older plants that just aren’t doing so well. There is a special pruning technique (actually I considered doing this with my hair when I saw how gray it has gotten). Many shrubs can be given a new lease on life with a severe renewal pruning.  This requires cutting the entire plant back to a stump. Although not all plants can be pruned this way, it works great for such plants as hollies or even azalias. Hollies and other non-grafted plants can be cut back to within six to twelve inches of the ground while grafted plants such as camellias should never be pruned below the graft line about fourteen to sixteen inches high. The resulting growth will be new, young, and vigorous but be patient because it will take some time for the plant to re-gain enough size to be attractive again. Junipers, pines, and many other narrow leafed shrubs do not have dormant buds on their main trunk and will die if severely pruned in this manner. Boxwoods, likewise should not be severely pruned as they are extremely slow to grow back. Pruning sealers or other products such as paint to cover the pruning wound is not necessary. The plant will heal itself just as well without them.

My second rule of pruning is very simple. Don’t be afraid to prune! Many people are so afraid of making a mistake while pruning that they either don’t do a good job or else skip pruning all together. Proper pruning takes practice and we all make mistakes. Most plants (with just a few exceptions) are very forgiving in that they will grow back and recover. At worst they’ll be slightly misshapen for a little while or else we cut off a few bloom buds. These things are bad, but the plant will recover and so will you. DON’T BE AFRAID TO PRUNE! If you are still not sure about pruning technique, timing of pruning or have other questions you can call us at the Extension Office at 221-3392.

My final rule of pruning is always keep your pruning tools sharp and in good condition. This includes hand pruners, lopers, shears, and a good pruning saw. Nothing will mess up a beautiful landscape plant, not to mention causing you great aggravation, like a set of dull pruners. Also keep a little WD-40 or three way oil handy to keep your tools lubricated. Finally, you will need a container of weak bleach solution (about 1 part bleach in 9 parts water) for sanitation. Rubbing alcohol works even better because it will not cause your pruners to rust. Dip your pruners into the bleach (or alcohol) solution after each cut and you will greatly decrease your chances of spreading diseases in your orchards, gardens, and landscapes.