Spring Pruning Do’s & Don’ts

— Written By and last updated by Leeann Crump

Spring is a great time to be outside taking care of garden tasks. The air is brisk, bird song fills the air, and it’s nice to finally get some exercise after being cooped up during this rainy winter. Pruning landscape plants is a common spring task, and understanding a few points helps make your pruning sessions successful.

Rule Number One: do not prune your azaleas in the Spring, if you want to have flowers! Spring flowering shrubs (like azaleas, rhodendrons, and forsythia) set their buds for flowers last summer. The rule of thumb for azaleas is to prune after flowering in the spring, and no later than July 4; pruning later than that will result in greatly reduced flowering the following spring. However, azaleas will often send up “sprouts”: gangly shoots that rise above the shrub, which can give azaleas a messy, untidy appearance. These individual shoots can be pruned back any time of the year; they typically do not have flower buds and pruning them will not diminish flowering.

There are several pruning tasks that can be done just about any time, and spring is a good time of year to do it, to clean things up for the new season. This includes the removal of dead, diseased, or crossing branches on the plant. Crossing branches creates the potential for branch wounding where branches touch and rub together. Removing one of the branches may prevent future problems and improves the overall appearance of the plant.

If you have a shrub that is overlarge and you are trying to reduce the size, the best time to do this task is after spring flush is completed; mid June would be ideal. You may cut back a plant by up to one third of the size without worrying too much about causing stress to the plant. The timing for the size reduction pruning is essential: If you cut back a large shrub with the goal of reducing size in the early spring, you will see an enormous flush of growth from the energy reserves in plant roots, and before long you will be right back where you started. Save size reduction pruning for June. Conversely, if you have a plant that has gotten “leggy” (with few leaves on the bottom) or generally has been allowed to get out of shape, early spring may be a good time do a “rejuvenating” cut. A rejuvenating cut is a drastic pruning done early before the spring flush of growth begins. It takes the plant back to about 12” tall, and is an opportunity to start over with shaping the plant almost “from scratch”. This type of cut should be limited to those plants that have vigorous “latent” buds, which will pop out and regrow the shrub once it is cut back. Azaleas and hollies do well with this type of cut. Obviously, if you do this with azaleas you will lose all your blooms for the year, but sometimes it is worth it to get a plant back in good shape. Keep in mind anytime a drastic pruning is done, there are rare occasions when the plant is so stressed that it will not survive. However, often this is type of pruning is the last resort to save a plant which otherwise would have it removed due to poor shape or over large size.

Some plants do not lend themselves to much shaping, size reduction, or rejuvenation. Junipers are easy care plants and are often long-lived in the landscape. Over time they often get much larger than was originally envisioned. However, junipers can not be cut back hard, beyond where there is active growth. If you notice how junipers grow, the active growth is toward the end of the branch; going down the branch into the interior of the plant there is no green growth. These plants do not have latent buds, so should not be pruned back past where there is green growth. If a cut is made beyond that point, there will not be any new growth to cover up the bare area.

Pruning is a necessary garden chore to ensure healthy plants in the landscape. When done properly, it is a pleasant, occasional task rather than a repetitive, onerous one. We have some excellent pruning resources at Cooperative Extension, so give us a call at 997-8255 if you have questions about how to prune a specific plant.