The Best Time to Trim Rhododendrons

Rhododendrons

• Also referred to as "rhodies," these large plants feature leathery, evergreen leaves and large clusters of flowers--often in reds, pinks, purples and white. One of the most important things you'll need to do is deadheading. This is the removal of all dead blooms once the flowering season has ended. Once the bloom clusters have lost their color and begun to dry up, simply snap off the bloom group at its base. This allows for new growth and prevents the plant going to seed. The energy of the plant will then be directed into root building and next season's flower buds.

Azaleas

• It's permissible to deadhead azaleas, too, but not as necessary. Although rhododendrons grow in a mostly uniform manner and don't typically require pruning, azaleas will occasionally send off an erratic or oddly spaced branch. You can remove these after the bloom season, but not after July, as the plant will begin its growth for the following year. Cut back the odd branch to keep it within the bounds of the overall plant shape.

Stem Bark Splitting

• If you live in an area that experiences periodic rapid temperature changes and freezing, your plants may suffer from stem bark splitting. The bark above ground splits and may peel off. Branches above the injury may subsequently die off, but not immediately. It can take a year or two. Trim back or cut out all branches that have been affected on your injured plants.

Other Concerns

• Yellowing leaves can be an indication of iron deficiency. There are treatments for this, such as spraying with an iron sulfate solution or mixing chelated iron into water to provide affected plants. Insects and disease problems are rare, but can occur. Solutions for any of these typically don't result in having to trim the plants. But if you notice any dead branches or sections, cut them out in late fall, winter or early spring.