Rose of Sharon shrubs are classified as hardy in USDA zones 5-8. Within those zones, they should overwinter easily, barring exceptional weather. If you are growing in zone 5 or 4, or expecting unusually cold weather, you may be wondering how you can help protect your plant to help it survive until spring?
The purple pillar rose of sharon (Hibiscus syriacus ‘Gandini Santiago’) is a stunning choice for gardens, known for its towering height and abundance of vibrant purple blooms in summer. But when frigid winter weather arrives, extra care is needed to ensure this beautiful plant survives the cold months and emerges healthy in spring.
Proper winter preparation and protection are crucial for purple pillar rose of sharon, even though it has excellent cold hardiness when established. Follow these tips to help your plant not just survive winter, but thrive through it
Overview of Purple Pillar Rose of Sharon
Before we get into winter care, let’s review what makes this variety so unique:
- Deciduous shrub with bright purple flowers blooming from summer into fall
- Narrow, columnar shape grows 10-16 ft. tall but only 2-3 ft. wide
- Hardy in zones 5-9
- Can tolerate cold winters in most areas
- Prefers full sun and moist, well-draining soil
- Low maintenance needs with little required pruning
- Deer resistant and attracts pollinators
Now that we’ve covered the basics let’s look at how to protect this plant through the tough winter months.
Is Purple Pillar Rose of Sharon Cold Hardy?
The purple pillar rose of sharon is rated hardy for USDA zones 5-9. This means it can generally withstand winter temperatures down to -20°F once established. However, even cold hardy plants benefit from some protection when conditions are severe.
For gardeners in zones 5-6, providing extra winter care is advised. Those in warmer zones 7-9 can relax a bit more, but should still take precautions.
Stop Fertilizing in Early Fall
Fertilizing should cease by early September at the latest. Late season fertilizer can spur new growth that is more prone to winter damage.
Ending fertilizer in early fall allows the plant to harden off naturally and focus energy on cold tolerance rather than new foliage.
Remove Dead Growth and Fallen Leaves
Before winter dormancy, trim off any dead or damaged branches. Removing spent foliage helps minimize disease issues.
Also rake up fallen leaves around the base, as they can harbor harmful fungal diseases over winter. Starting with a clean slate promotes health.
Water Infrequently After First Frost
Once light frosts begin, discontinue frequent watering. The soil should not stay soggy wet heading into freezing weather.
However, a deep watering every 2-3 weeks during winter dry spells is beneficial. Roots still need occasional moisture when dormant.
Add Insulating Winter Mulch
Placing 2-4 inches of shredded bark, leaves, straw or other organic mulch around the base provides insulation against harsh winds and temperature swings.
The extra protection keeps soil warmer and roots protected. Let the ground freeze before applying winter mulch.
Protect With Burlap or Screening
For additional protection in zones 5-6, wrap plants with burlap or commercial protective screening to buffer from desiccating winds.
Avoid plastic wraps that prevent airflow. Secure coverings loosely to avoid damaging branches.
Prevent Damage from Heavy Snow
The columnar shape makes purple pillar prone to potential stem and branch damage if heavy snow or ice accumulates.
Carefully knock off buildup with a broom. Prune away any split or broken branches in early spring.
Delay Pruning Until Spring
Avoid pruning in late fall or winter, as this can encourage vulnerable new growth. Save pruning for early spring after the worst of winter passes.
Watch for Pests Like Scale
Inspect plants prior to winter for scale infestations. Remove any visible scale with a scrub brush or natural oil spray. Unchecked scale weakens plants over winter.
What to Expect in Winter
Here are some common changes and challenges to expect with purple pillar rose of sharon during cold months:
- Defoliation as leaves drop before dormancy
- Minor dieback of tender branch tips due to frost
- Flower buds set on new wood, so blooms unaffected
- Freezing and thawing damages roots if soil isn’t mulched
- Harsh winds or heavy snow can cause stem breakage
With proper winter care, the purple pillar rose of sharon will thrive for years in zones 5-9. A little extra protection makes all the difference for these stunning bloomers!
By providing attentive care and protection during the cold months, your purple pillar rose of sharon will be poised for another sensational floral display when summer returns. Just a bit of preparation will go a long way toward ensuring this unique plant remains an eye-catching focal point in your garden.
Watering Rose of Sharon in Winter
Whether in a pot or growing in the ground, it’s important to make sure your plant has enough water in its system before it freezes. Water thoroughly before an anticipated frost or cold spell. Mulching is helpful to hold warmth in the top layer of the soil.
Subsequent watering is only needed if the winter fails to supply rain and snow regularly, in which case, water when dry to two inches deep – an inch of water a week is a good rule.
Cutting Back Rose of Sharon for Winter
Roses of Sharon are deciduous shrubs, so will lose their leaves in fall. Pruning, usually done for shaping and improving air circulation, can be done any time between leaf-drop and bud break in spring. If you are concerned about rose of Sharon being hardy in your area, leave the pruning until late winter so there will not be fresh cuts open to the weather.
30 Seconds with Purple Pillar® Rose of Sharon
FAQ
What to do with Rose of Sharon in winter?
Pruning: Prune Rose of Sharon in late winter or early spring (rose of Sharon blooms on new wood) to remove any dead or damaged wood and to shape the plant as desired. Pruning can also help promote flowering and control the size of the shrub. Avoid heavy pruning, as this can reduce flowering in the following season.
Should Rose of Sharon be cut back for winter?
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Timing is key:Pruning in late winter/early spring allows you to enjoy the blooms later in the season without sacrificing next year’s flowering potential.
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Purpose of pruning:Pruning helps maintain the plant’s shape and size, encourages more robust branching, and promotes larger blooms.
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What to prune:Remove any dead, diseased, or damaged branches, as well as any branches that are crossing or growing into the center of the plant.
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Renewal pruning:For older shrubs, consider renewal pruning by removing one-third of the largest, oldest, or weakest branches to the ground level. This encourages new growth and larger flowers.
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How much to cut back:You can prune back about one-third of the shrub’s wood each year to maintain size or promote branching.
Can you prune the purple pillar rose of Sharon?
Pruning: Rose of Sharon needs little to no regular pruning. If you wish to prune, however, late winter or early spring is the best time to do so. Up to one-third of the plant can be removed at a time.
What do you do with a hibiscus plant in the winter?
They will soon produce new growth. Hibiscus overwinter best indoors if provided with bright light and warm temperatures.
Does Purple Pillar Rose of Sharon spread?
Discover More Information On Purple Pillar® Rose of Sharon
Unlike its wide-spreading counterparts, the Purple Pillar® grows in a narrow column, reaching a height of 10 to 16 feet while maintaining a modest spread of 4 to 5 feet.
Why is my Purple Pillar Rose of Sharon not blooming?
If your Rose of Sharon is not blooming and you give it the right amount of water and sun, it may be that your shrub isn’t getting enough phosphorous. This should be the last step if none of the above helps. This is easily fixable with a high- phosphorus, low-nitrogen fertilizer every couple of weeks.