Brueckner Rhododendron Garden Head Gardener demonstrates how to prune Rose of Sharon, a late summer blooming shrub in the hardy hibiscus family, and offers these How-to tips:
- When to Prune: Now; early spring in Mississauga, Ontario
- How to Prune: Open method, not closed
- How much / how many canes (branches) to prune
- How to control or maintain shrub height
- When to fertilize: After Pruning, and regularly all season
|Rose of Sharon shrub before pruning ~ Head Gardener BRG Mississauga|
This is the time to prune Rose of Sharon, and other summer flowering shrubs.
Tip: This is also the time to prune roses, so think Rose of Sharon = roses. (See Pruning Roses on this page.)
This long-unpruned Rose of Sharon was transplanted to its new home in BRG last summer, a mass of tangled and crossed branches. But, having survived the winter, it's now time to give it a good pruning, with a goal to open up the crowded interior of the plant to let air and sunlight in. This is the Open method; the Closed method is trimming off all branches on the outside of the plant, more suited to hedge plants and topiary.
|Rose of Sharon ~ Count the Canes Before Pruning|
And to determine how many branches you may safely remove (prune), you must first count what is there, including any damaged or dead canes.
In the shrub above, there are 9 main canes (branches) coming from the ground, so three canes including dead and damaged canes could be removed.
|Pruned Canes (Branches) Rose of Sharon|
First decide which, if any, of the main canes to prune. Give priority to canes that have visible damage in the bark, or have been broken over the winter, or canes that are crossing or rubbing against their neighbours.
|Prune to Open Center of Rose of Sharon|
Determine which branches are growing inward, or rubbing against other branches, or show breakage or other damage. As well, prune out any weaker, smaller branches that will not produce healthy blooms yet will sap the shrub's strength if left in place. All of these should be pruned out.
Again, try to prune no more than one third of the length of any branch. Select a cane, look for an outward facing bud, and prune just above the bud on a 45 degree angle or slant.
|Maintain or Control Height of Rose of Sharon|
The height of this Rose of Sharon in the photo is fairly low, around 6 feet high, and can be pruned when standing on the ground. Note not all branches are the exact same length, but generally the same height. Where each cane is pruned depends on where the outward facing bud is on the branch.
|Rose of Sharon After Pruning Mississauga Ontario in Spring|
Rose of Sharon blooms on new wood, and regular feeding over the coming months will encourage lots of new growth and buds that will be a gorgeous show in mid to late August, about 4-5 months from now.
|When Crocuses Bloom, Prune Rose of Sharon and Roses.|
Here's a video of the pruning this day:
Pruning Rose of Sharon
General Pruning TipsThese are good pruning tips for all shrubs, but do not prune Spring flowering shrubs and trees such as spirea, flowering almonds, cherries, etc., until AFTER they have bloomed this season.
Rhododendrons are spring bloomers, and will be pruned for shape and to remove dead wood in mid to late June. Rhododendrons also need spent blossoms removed after flowering, so it is a two-part process. Not all rhodos will need branches pruned, but all will need old blossoms removed.
Rose of Sharon August 2011
|Rose of Sharon Full Bloom|