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Pruning guide: Why? When? How?

The wind hit hard as February waned, damaging structures, vehicles and, most of all, trees. Late winter is the right time for most pruning anyway – a surprise to many – but now the task at hand is “corrective pruning.”

What can you do, and how should you do it, to salvage or improve your beloved shrubs and trees?

Storm-damaged trees

Decision No. 1: What is worth trying to save?

• Blow-overs: If a tree blew over and the root system has been hanging out in the air for a couple of weeks, it’s probably too late to fix. If it’s a valuable plant, consult with an arborist soon. You may be able to salvage the good roots in the soil and trim others. If you catch a blow-over quickly: Right the plant, surround the roots with compost to avoid air spaces, stake it and weigh down the uprooted side to hold it in place until the roots take hold.

• Stripped and wounded bark: When a broken branch strips the bark down a tree trunk, the most important information is how far does the wound reach around the trunk? If the bark is removed or cut more than one-third around the circumference, it’s generally considered a lost cause. Remove the tree for safety and to spare it the inevitable, undignified death.

• Valuable plant/expendable plant: Some trees such as silver maples, Norway maples and Bradford pears are no longer considered great choices, and you may have others that no longer appeal or serve a purpose. If damaged, let them go. Then consult with pros and do the homework: What plant would suit your yard better?

Decision No. 2: What can you do yourself?

You can certainly cut off broken branches and pick up the fallen debris yourself. Learn how and where to prune, and when to stop. If someone who loves you says, “That could be dangerous …” believe it. Or give yourself smart advice.

• Don’t do anything higher than your head with a chainsaw or any cutting tools.

• Don’t get on a ladder with sharp objects, unless you are a professional.

• Don’t pull or cut big fallen limbs off that have weighed down other branches. There is a powerful snap-back response that can smash anything in its wake – including your face.

Most shrub and tree damage can wait until a CNLP or certified arborist gets to you. Exceptions are uprighting a valued plant as soon as possible, and cutting off a broken branch so it can’t strip the bark any further. But make safety your first consideration.

Pruning rules

Broken or not, many of your woody plants call for pruning – and this is the right time for most. With these pruning principles you can improve the health and appearance of many landscape plants. For the work that’s too much to do yourself, get professional help and discuss the work in depth.

1. At any time of year remove diseased, dead or broken branches or limbs (done properly). Also remove limbs that rub against each other, tracing them to points lower in the plant and choosing one to remove. (Rubbing leads to wounds.)

2. If bark is pulled off or flapping, use a sharp knife to make clean edges. Don’t cut deeper than the bark, and do not use wound paint.

3. To cut broken branches from a tree trunk: Do not cut flush with the trunk. Do not leave stubs. Do cut just outside the swollen parts, where branch meets trunk, called the “branch bark ridge” or “branch bark collar.” That’s where the vital calls are that can seal off the wound.

4. Never top trees, and don’t flat-top shrubs unless you must have a hedge. Flat cutting or topping produces crowded, weak, thick new growth that is neither healthy nor attractive. Shrubs that are topped end up with a top layer of green and all bare sticks beneath.

5. Multistemmed shrubs may benefit from thinning, by taking out selective branches from inside the plant. (Proven Winners has an article and illustrations online highlighting basic pruning principles. Check it out here.)

You may also head back some branches by cutting them back to a bud or branch that faces in a preferred direction. Most shrubs would be naturally beautiful without any pruning.

6. Wait to prune spring-flowering plants such as lilacs until after they flower. (You’d be cutting off the flower buds.) Don’t cut back Big-Leaf Hydrangea stems now (in case flower buds may emerge in the stems.) Don’t prune roses until midspring, when forsythias bloom.

The big lesson

Extreme weather can certainly wreak havoc, but healthy plants in the right sites will thrive and survive most storms, pests, diseases and predators. Most plant problems are cultural. Choose plants that belong where you put them, considering wind, floods, soil and human-imposed threats.

Choose woody plants that will not outgrow the location. If you are continually pruning to make something smaller, it is in the wrong place. Care for plants properly during the first years of establishment.

So much depends on us to prevent the damage of the future.

Sally Cunningham is a garden writer, lecturer and consultant.

* Here is Sally Cunningham's last column:

Sally Cunningham: Extreme weather and your plants

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