Due to the dry winter and cold spring we experienced, many shrubs died back more than they normally would. So, how should you prune a shrub with a lot of dieback?
Here’s a four-step pruning approach for shrubs with thin stems. This approach will work for shrubs like potentilla, dogwood and any of the small spireas. The shrub featured in the photos is an Anthony Waterer spirea (Spirea x bumalda ‘Anthony Waterer’). Here’s a four-minute video where I demonstrate how to prune an Anthony Waterer spirea with dieback.
Step 1: Look closely at what you’re dealing with.
When you take a good look, you’ll notice there are three types of stems on a twiggy shrub with dieback. First, there are stems that are totally dead all the way to plant’s interior. You can recognize them because they have no new leaves at all, plus they snap when bent. Second, there are new stems this year, growing from the crown. These stems are green and supple with fresh leaves. Third, there are stems that died back partway, leaving the upper portion dead and the lower portion alive (with leaves).
Step 2: Cut out all the dead stems.
The first thing to do is to cut out all the dead stems (those with no leaves). Grab one by its tip, pull it to the side slightly so you can trace it towards the base of the shrub, and cut it as low as possible without cutting any of the new stems.
Usually, you can cut the dead branch at least a couple of inches below the height of the leaves on the new branches. By cutting it below the height of the new leaves, you’ll hide the cut stub from view. This practice makes the shrub look better when you’re finished. If you cut the dead stems above the new growth, you’ll have to wait for several weeks for the new growth to cover up all the cut stubs.
Avoid cutting any of the new stems emerging from the crown. Especially avoid randomly cutting their tips by shearing the plant. If you cut too many new stems, the shrub will look like it got a bad haircut.
Step 3: Cut off the dead portions the stems with partial dieback.
With dead stems removed, you’ll be able to work on the stems with partial dieback much easier. Cut off the upper dead portion of the branch with no leaves. Snip the stem right above a healthy leaf. Don’t worry too much about the shape of the plant at this point. Your goal should be simply to remove the dead portion of the branches.
Step 4: Prune for symmetry.
Once you’ve removed all the dead material, step back and take a look at the shape of the plant. It’s probably going to have a strange, asymmetrical shape.
To improve its appearance, try to envision the shrub as a mound. Then cut a few of the longer branches above a healthy leaf to create the mound shape.
Avoid cutting back all the live branches. If you cut all of them, you’ll get too much branching at the same height. The shrub will look strange when it loses its leaves in the fall.
This also includes shearing. Don’t shear your shrubs into balls. Take the time to prune them carefully and they’ll look great for the rest of the summer.
Although a shrub with significant dieback will be smaller than normal, it’s usually possible to prune it into healthy, attractive asset for your landscape. Smart pruning will allow the shrub to recover in future years.
Just in case you missed the link above, here’s a four-minute video where I demonstrate how to prune a shrub with dieback. Enjoy!