Pruning Techniques
Pruning timing, heading vs thinning cuts, crown work, branch bark ridge, deadheading, and proper cut angles.
- Determine correct pruning timing for spring-flowering and summer-flowering shrubs
- Distinguish between heading cuts and thinning cuts and their effects on growth
- Identify the branch bark ridge and branch collar for proper pruning cuts
Lesson 1
Pruning Timing for Spring & Summer Bloomers
The Timing Rule
The most important pruning principle for the Red Seal exam is knowing WHEN to prune. The rule is based on when the plant flowers and when it forms its flower buds:
Spring-flowering shrubs (lilac, forsythia, azalea, rhododendron) bloom on old wood - branches that grew the previous year. These plants form their flower buds in late summer or fall. The best time to prune spring-flowering shrubs is immediately after flowering. If you prune them in fall or winter, you remove the flower buds and the plant will not bloom the following spring.
Summer-flowering shrubs (butterfly bush, hydrangea paniculata, potentilla) bloom on new wood - the current season's growth. These plants can be pruned in late winter or early spring before new growth begins, because they will form flowers on the new branches that grow after pruning.
Spring Bloomers - Prune After Flowering
Bloom on old wood
Lilac - prune right after May bloom
Forsythia - prune after April bloom
Azalea - prune after spring bloom
Wait until flowers fade, then prune
Summer Bloomers - Prune in Late Winter
Bloom on new wood
Butterfly Bush - prune hard in March
Hydrangea paniculata - prune in early spring
Potentilla - prune before new growth
Exam Tip
When the exam asks "When is the best time to prune spring-flowering shrubs?" the answer is always immediately after flowering.
Prune spring-flowering shrubs immediately after flowering. Prune summer-flowering shrubs in late winter or early spring. This is based on whether the plant blooms on old wood or new wood.