There’s a Facebook page titled “Crimes Against Horticulture” that gathers photos of horrendously mutilated trees and shrubs. It’s what people do when they feel compelled to prune plants, but they don’t know why. The extent of human creativity can be viewed on their posts, which defy both logic and nature. It is a valuable, visual cautionary tale about what power tools have done to landscape plants everywhere.
Early in my career, my 80-something mentor, landscape architect Milton Sessions, taught me about pruning woody shrubs and trees his way. First of all, he said, “They should never look like they are pruned and I don’t want to see any blunt ends.” I was specifically tasked with shaping the old shrubs in a way that results in a natural-looking plant. He demonstrated how to remove wayward branches deep inside the branching structure to create the results I want on the outside. “Sure it takes longer,” he explained, “But you won’t have to do it again for a very long time. Use clippers to shape your old shrubs and you’ll ruin them. You’ll have to do it often and for the life of that shrub.”
Sessions taught me another simple rule about how to approach maintenance pruning on woodies that’s ideal for beginners: “Always begin by removing all dead, diseased or conflicting branches first.” These are three conditions that may threaten the health of the plant by creating injuries where moisture is lost and pathogens flourish. Wounds also draw off growth energy to nonproductive parts of the tree. Fortunately these are easy to spot and resolve without special training.
With deciduous plants, dividing dead wood (twigs or branches) from living is impossible in the winter. Afterwards when leaves come, dead wood stands out like a sore thumb. Early in the season is the best time to spot and remove these three scenarios so wounds can heal completely before winter.
CONFLICTING WOOD
Whenever two branches or twigs touch there is a wound. It gets worse every time the wind blows, sawing the bark back and forth until it’s worn off. This is where internal moisture flows out and disease comes in. You must resolve every conflict by deciding which branch takes priority, then sacrifice the other. Make your decisions on which one is healthiest and contributes most to the overall beauty of the form.
DEAD WOOD
Whether it’s cold or heat or drought, plants show their displeasure with tip die back. They sacrifice parts of the canopy to minimize the amount of foliage it must support. Die back is caused by many things, but no matter the source, it should be immediately removed to stop any spread into fresh wood. When removing dead wood, make sure you cut further down into the green wood so living cells will callus off the wound securely against pathogens.
Insiders hide large tree cuts by washing the open wound with watered down interior latex (tinted to match the bark) paint for more immediate protection and to discourage moisture loss and unsightly sap bleeds.
DISEASED WOOD
You may notice rot, peeling bark, bugs, black fungus and a dozen other typical problems. The easiest way to keep any of it from spreading from a small spot to the rest of the tree is to simply prune it off and discard. Branches invaded by mistletoe must be cut a foot back from this tree parasite to make sure all its root-like haustoria are removed.
I quickly learned that after completing these three requirements with most any plant, there was no further pruning to be done. Once a year natural pruning was vastly preferred by this lazy gardener over tedious shearing and clean up which has proliferated with cheap power tools, the gateway to future crimes against horticulture.
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Maureen Gilmer is an author, horticulturist and landscape designer. Learn more at www.MoPlants.com
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