Last Updated on March 17, 2024 by Kimberly Crawford
If your forsythia, rhododendron or weigela has no flowers it’s most likely caused by cutting it back at the wrong time. Knowing when a shrub blooms will solve the problem.
In Rhode Island (USDA Zone 6), the forsythia blooms in April. If it was looking shaggy last July and you sheared it back, you can bet that you won’t have much of a bloom this year.
Most Spring flowering shrubs, like forsythia, start growing their flower buds for the next season within just a few weeks of finishing the current year’s blooming. Remember this fact and you’ll know which shrub to prune when, and you’ll never prune at the wrong time again.
Spring Flowering Shrubs
#1. Forsythia
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 21 forsythia plant](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/forsythia-plant.jpg)
#2. Pieris
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 22 Pieris](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/pieris-plant.jpg)
#3. Rhododendron
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 23 rhododendron](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/rhododendron.jpg)
#4. Azalea
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 24 azalea flowers](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/azalea-flowers.jpg)
#5. lilac (Syringa)
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 25 lilac (Syringa)](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/Syringa-lilac.jpg)
#6. Mock orange (Philadelphus)
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 26 philadelphus plant](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/philadelphus-plant.jpg)
For shrubs that blooms in the Spring, do your pruning within 2 weeks after the shrub has finished flowering and then leave it alone for the rest of the season.
If it’s absolutely necessary you can remove a few straggling branches but cut them out one-by-one on an as-needed basis so the flowers on the rest of the shrub remain. Do not shear the entire shrub at this time or all the blooms will be cut off, ruining next season’s show.
Summer or Fall Flowering Shrubs
#1. Spiraea
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 27 spiraea](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/spirea-plant.jpg)
#2. Weigela
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 28 weigela](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/weigela-plant.jpg)
#3. Butterfly bush (Buddleia)
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 29 butterfly bush (Buddleia)](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/buddleia-davidii.jpg)
#4. Blue mist shrub (spigela)
#5. Rose of Sharon (Hibiscus)
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 31 Rose of Sharon (Hibiscus)](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/Hibiscus-plant.jpg)
#6. Summersweet (Clethra)
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 32 Summersweet (Clethra)](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/summersweet.jpg)
Shrubs that bloom in June, July, August or September can be pruned in late winter to shape them up for the coming season. But don’t wait until the middle of Spring to do it because most of the shrubs in this group start making the season’s flower buds in the Spring.
Cut these shrubs back as hard as necessary just as they begin to leaf out. As with the Spring-flowering shrub group, selective pruning throughout the growing season is okay – just don’t take out the hedge shears to do the job. Use small hand clippers or loppers to just cut the branches that need to come off.
Best Time to Prune Evergreens
Related: 39 Small and Dwarf Evergreen Shrubs For Small Landscapes
#1. Yew (Taxus)
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 33 Yew (Taxus)](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/yew-Taxus.jpg)
#2. Juniper (Juniperus)
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 34 Juniper (Juniperus)](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/juniper-plant.jpg)
#3. Pines (Pinus)
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 35 Pines (Pinus)](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/Pines-Pinus.jpg)
#4. Spruce (Picea)
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 36 Spruce (Picea)](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/Spruce-Picea.jpg)
These should be pruned when they are dormant. Here in USDA zone 6 that means mid-December, January and February. The act of pruning kick starts a chemical reaction in the plant that sends out new growth.
When the cuts are made just before Spring the result is lush new foliage and branching in the coming season. If the cuts are made in late Summer or Autumn the new growth that emerges will probably be killed by frost before it has time to mature enough (aka harden off) to survive the winter. This rule also applies to deciduous shrubs like:
- burning bush (Euonymous alatus)
- Harry Lauder’s Walking Stick (Corylus avellana ‘Contorta’)
- shrub dogwood (Cornus alba)
A Word About Hydrangeas
![When to Prune Shrubs For Better Blooming: Trim Shrubs at the Right Time So You Don't Cut Off the Flowers 37 Hydrangeas](https://images.farmfoodfamily.com/wp-content/uploads/2018/10/Hydrangeas.jpg)
It’s important to know what variety of hydrangea you have to determine how to prune it. Generally, the older hydrangeas (Hydrangea macrophylla) can be pruned after flowering. The newer varieties such as Endless Summer ™ (also H. macrophylla) hydrangeas are bred to bloom on new or old wood so timing doesn’t matter as much.
Hydrangea paniculata, which is popular in tree form, blooms on current season growth so it can be cut back just before Spring comes. When in doubt about what type of hydrangea you have do your research and use a very light hand if you aren’t sure.