When to Trim Evergreen Shrubs?

Cut off fungal-diseased areas of the shrub anytime of year to control the spread of the disease.

Gardeners often need to prune their evergreen shrubs to reduce the size, maintain the shape, remove damaged areas or cut off diseased portions. The time to prune depends on the type of evergreen shrub growing in your yard. Prune certain evergreen shrubs, such as evergreen barberry, right after they blossom. Wait until spring, however, to prune others, such as junipers.

Identification

Two types of evergreen shrubs exist: Broad-leaved evergreens and narrow or needle-leaved evergreens. It's important to correctly identify the type of shrub growing in the yard to help determine when to prune. Examples of broad-leaved evergreens include azaleas, andromeda and holly. Types of narrow or needle-leaved evergreen consist of hemlock, yews and chamaecyparis. Prune these two types of shrubs at different times of the year -- or experience reduced blossoms the following year.

Broad-Leaved Evergreen Shrubs

Prune broad leaved-evergreen shrubs as soon as they finish blossoming or before July. Flowers set for the next year in the summer. If you prune after the shrubs have set their flowers, you will see bare spots where flowers are not produced. Shrubs that need complete rejuvenation can be cut down in the early spring, because it will take a year for the plant to grow and recover from the pruning. You know if you broad leaved-evergreen needs to be completely rejuvenated when it has grown too large for its location or produces leggy looking growth.

Narrow or Needle-Leaved Evergreens

For narrow or needle-leaved evergreens, prune in the early spring. Prune pine shrubs before new growth or candles grow after winter. It is essential to monitor the plant for new growth soon after the last frost for your region. Don't cut too much into the shrubbery of needle-leaved evergreens, because you will wind up with bare areas in the shrub.

Winter

Gardeners must not prune their shrubs in the late fall regardless if they have a broad-leaved or narrow-leaved shrub. Shrubs when pruned in the fall produce new growth that gets damaged in the winter. Freezing temperatures and snow will cause the new growth to die off, and in the spring you will have either browning of foliage or defoliated shrubs.

References

• Online Gardener: Pruning Evergreen Shrubs
• Texas A&M: Proper Pruning Techniques
• Terry L. Ettinger Horticulture Consulting Services: Question of the Week