CSLB C-27 Landscaping ContractorPlanting and LandscapingMedium
A landscape contractor is performing annual maintenance on a client's property. They notice that several ornamental shrubs, which are known to flower on old wood, are producing very few blooms. Upon inquiry, the client states they had the shrubs 'shaped up' by another gardener late last fall. What is the most likely reason for the reduced flowering?
- AInsufficient fertilization during the growing season.
- BPest infestation that damaged flower buds, but not foliage.
- CPruning was performed at the wrong time of year for 'old wood' flowering shrubs.
- DDrought stress during the previous summer inhibited bud formation.
Show answer & explanationAnswer & explanation
Correct answer: C. Pruning was performed at the wrong time of year for 'old wood' flowering shrubs.
Shrubs that flower on 'old wood' (e.g., Hydrangea macrophylla, Forsythia) form their flower buds on stems produced during the previous growing season. Pruning these shrubs in late fall or winter removes these pre-formed flower buds, resulting in significantly reduced or absent flowering the following spring or summer.
Why the other options are wrong
- A. While fertilization affects overall vigor, incorrect timing of pruning is a more direct and common cause for reduced flowering on old-wood bloomers.
- B. Pest damage to flower buds would likely be visible upon inspection and might also affect foliage, which isn't mentioned.
- D. Drought stress can inhibit bud formation, but the scenario points to a recent 'shaping up' (pruning) event as the most direct cause of missing flowers on old-wood bloomers.
Pruning Old Wood Bloomers
Pruning shrubs that flower on 'old wood' (previous season's growth) should be done immediately after they finish flowering to avoid removing next year's flower buds.
- Flower buds form on previous year's stems.
- Prune after flowering, before new buds set.
- Fall/winter pruning removes flower buds.
Memory trick: For 'old wood' flowers, 'prune after bloom' or 'lose the show'.