Hardy in zones 5-10, rose of sharon, or shrub althea, allows us to grow tropical looking blooms in non-tropical locations. Rose of sharon is usually planted in the ground but it can also be grown in containers as a lovely patio plant. One problem with growing rose of sharon in a pot is that it can get quite large, with some species growing up to 12 feet (3.5 m.). Another problem with rose of sharon in pots is that it may not be able to survive harsh winters without suitable care. That said, winter care for rose of sharon planted in the ground may be required. Continue reading to learn more about overwintering rose of sharon.
Preparing Rose of Sharon for Winter
While generally we are not thinking about winter in July, it’s important to know not to fertilize these shrubs after this month. Fertilizing too late in summer can cause tender new growth to grow, which can be damaged by frost later. It also wastes the plant’s energy on this new growth, when it should be putting energy into developing strong roots that can withstand the winter chill.
Rose of sharon plants bloom in late summer to early autumn. In October, the flowers fade and develop into seed pods. The seeds that develop are a source of winter food for goldfinches, titmice, cardinals, and wrens. The remaining seeds drop close to the parent plant in the winter and may germinate in spring, creating colonies of the shrub.
To prevent unwanted plants, deadhead rose of sharon flowers in late fall. You can also collect these seeds for later plantings by putting nylon pantyhose or paper bags over the developing seed pods. When the pods split open, the seeds will be caught in the nylon or bags.
Rose of Sharon Winter Care
In most zones, preparing rose of sharon for winter is not necessary. In zone 5, though, it’s a good idea to add a heap of mulch over the plant crown for protecting rose of sharon in winter. Potted rose of sharon may need winter protection as well. Either heap mulch or straw over potted plants or wrap with bubble wrap. It’s most important that the plant crown be protected in colder climates. Protecting rose of sharon in winter when it’s planted in areas of high wind may also be necessary.
Since rose of sharon blooms on new wood, you can lightly prune, as needed, throughout the year. Any heavy pruning should be done as part of your rose of sharon winter care regiment in February and March.
Rose of sharon leafs out later in spring than many other shrubs, so if you cannot get out to prune it in February or March, just do it before new growth begins in spring. Do not do heavy pruning of rose of sharon in autumn.