Gardening

With good timing and technique, pruning will help your plants flourish

Person pruning a tree with red clippers

I’ve received a few notes from folks who are concerned about tree limbs. They are not referring to all those branches that are on the ground as a result of all the strong winds we had. Instead, the concern is removal of unwanted limbs, aka pruning. When is the best time to prune, they ask?

I don’t spend enough time on pruning. Sure, I always mention that if you are going to prune a lilac, the time to do it is immediately after flowering as they set buds soon thereafter and you want yours to have maximum blooms the following year. This is the same advice I give when it comes to most spring-flowering shrubs such as forsythia and rose trees of China (prunus triloba).

In fact, it is best to prune most spring-flowering things right after they flower. There is enough time for them to start on next year’s crop of flowers. Alaskans grow lots of lilacs, but in addition, mock orange, spirea, spring-blooming clematis, cotoneaster and viburnum flower early enough to be prune immediately — relatively speaking — after they flower so they can form next year’s buds.

When it comes to other shrubs, late winter is the best time to prune. The same is true for trees, including fruit trees. Note the use of the term “best,” as you should prune these plants anytime if the occasion demands it — like a limb might fall on one of your cars or the greenhouse or the limb is blocking a window. In those cases, don’t wait.

There are real reasons for pruning in late winter. For one, you can see the silhouette of the branches because there is no leaf cover. You can tie rags or put tape on the limbs you want removed. Sometimes it is hard to tell which limbs are dead and which are not when there are no leaves, but it isn’t that difficult.

The main reason late winter is the better time to prune, however, is because plants produce new cells at this time. They are starting the growth process for the season. These cells help your pruning cuts to heal quicker.

How you prune has a lot to do with why you are doing the chore. Fruit trees, for example, are pruned at the end of winter because it encourages new growth which improves fruit production. Branches are removed to keep the the canopy open so they get great sun and have space for fruit. Remove unwanted suckers so things don’t get crowded.

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Most evergreen trees only need pruning at their bases. This opens up the canopy so there is adequate air circulation and can improve your view. Evergreens have leader branches at their tops which helps keep their shape, but you may need to stop in and do some trimming.

Deciduous trees may need shaping. Dead or weakened limbs need to be removed, too. Look for crossing branches which rub and create visual disturbance and remove one. Also branches on deciduous trees are not supposed to grow downward. Remove these too.

Cuts on trees should be to a lateral branch or trunk. Always leave a bit of the stub rather than cut right to the bark. This way a healthy, protective “collar” will form as the wound heals. Make your first cut under the limb and then cut from the top. This will prevent the limb from falling and peeling off the bark. Do not use healing paints or salves. Let the branch cut heal naturally. This is why you are doing this in late winter.

Cut shrub branches, roses in particular, back to a bud that faces outward, not inward toward the plant. The cut should sling downward so it won’t collect water and rot. Cut bigger limbs back to a lateral branch.

Each plant has its own pruning needs. The general goals are to shape the tree or bush for landscape needs and to guide future growth, to remove limbs that are dangerous and might cause harm. You also want to get rid of “weaknesses,” such as branches creating sharp V-shaped notches, which can split.

Obviously, I have only scratched the surface. In addition to sharp tools, you will want to spend a few minutes on the internet seeing how to prune the specific type of plant you have to work on. There are great articles and videos. It is a popular subject.

So, pick a nice day when you can work “happily” outside, but don’t wait too long. Those new cells are forming. Those birch leaves will be the size of a squirrel’s ear before we know it. Thank goodness!

Jeff’s Alaska Garden Calendar

Alaska Botanical Garden: Time to join. Discounts, nursery plants etc. www.alaskabg.org

Flower seeds to start: Lobelia , snapdragons, carnation, Verbena, Pelargonium, gladioli.

Herb seeds to start: Lavender, lovage, lemon balm, oregano

Vegetable seeds to start: Tomatoes if you have a greenhouse or room and lights.

Jeff Lowenfels | Alaska gardening and growing

Jeff Lowenfels has written a weekly gardening column for the ADN for more than 45 years. His columns won the 2022 gold medal at the Garden Communicators International conference. He’s authored several books on organic gardening, and his latest book, "Teaming With Bacteria," is available on Amazon. Reach him at jefflowenfels@gmail.com.

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