Roses of Sharon, in the same family as hibiscus, hollyhock, and mallow, are adored for their long and abundant bloom season. They can often bloom for months in summer given optimal conditions. What if your plant is not blooming, or the buds are failing to open, or falling off? Perhaps the location is not offering the best exposure, or the area is too crowded. There can be several reasons why a rose of Sharon may stop or slow its bloom. Let’s examine them.
Common Reasons Why Rose of Sharon Isn’t Blooming
The simplest reason for fewer flowers may be it’s not getting enough sun. Roses of Sharon bloom best with full sun, defined at six or more hours of direct sun. This is usually found in open southern or western exposures.
Stress from over or under watering can cause rose of Sharon shrubs to drop its flower buds, cancelling your summer show. While drought-tolerant once established, these plants like consistent moisture with excellent drainage.
Pruning too late in the season can be another cause. If you prune after flower buds form in the spring, you can delay or remove your flowers.
While fairly deer-resistant, roses of Sharon can be chomped if your local deer are ravenous. If so, prune the damage and hope you have time in the season for new flower buds to bloom.
Pruning Rose of Sharon to Help it Bloom
Pruning is very beneficial to rose of Sharon bushes. Roses of Sharon bloom on “new wood” from the current season. The ideal time to prune is from fall through late winter (after leaf fall and prior to buds breaking).
An annual pruning to clean up the plant encourages as much new wood as possible (= more flowers) and increases air circulation around the stems. This discourages diseases like fungus, or powdery mildew which can weaken the plant and its flowering for the season.
Deadheading (removal of spent flowers) is only necessary if you are concerned about preventing seedlings in your garden. This isn’t necessary if you have a newer, sterile variety. Unlike some annual flowers, deadheading will not promote new blooms in the same season.
Fertilizing Rose of Sharon to Help It Bloom
Will fertilizer boost the blooming on your rose of Sharon? Roses of Sharon prefer a lean diet overall. They don’t need much in the way of fertilizer. If you want to give a young plant some help becoming established in the first year or two in your yard, consider adding some organic slow-release fertilizer in spring. The ratio of nutrients (N-P-K) should be either balanced as in a 10-10-10 formula, or higher in phosphorus (the middle number). A formulation with very high nitrogen (N) will spur foliage growth at the expense of flowers.
If your soil is depleted, a surface application of compost annual in fall will foster good soil and nutrition uptake.
Get Rose of Sharon to Produce More Blooms
If you want to encourage your rose of Sharon to flower more, first check that it’s in a full sun location. Make sure it’s getting consistent water but that the soil drains easily. Then evaluate your pruning – an annual pruning done from fall through late winter will encourage the fullest blooming. If you prune after buds emerge, you may cut off the flowers. If you don’t prune at all, the plant will grow leggy with sparse blooms at the top.
Why Rose of Sharon Isn’t Blooming
- It’s not getting six-hours of sun.
- It’s getting too much or too little water.
- It wasn’t pruned.
- It was pruned at the wrong time.
- Deer pruned it.