The rose of Sharon (Hibiscus syriacus) is a deciduous shrub that blooms in late summer. Rose of Sharon is a tall shrub, reaching heights of twelve feet and widths of six feet. Make sure you leave enough room in your garden for this shrub.
The rose of Sharon puts on leaves late in the spring, so do not be alarmed when there are no leaves on your tree and other trees are growing leaves. When they do come in, leaves are three to four inches long with three lobes and jagged edges. The flowers are two to five inches wide, in shades of white, pink, red, blue, purple, and violet.
Rose of Sharon thrives best in loamy soil with lots of organic matter. In order to produce soil like that, you should till to a depth of six inches and then put three inches of compost on the soil. Till it again to mix it in well. Make sure the flower bed you put the rose of Sharon in is in a sunny, well drained spot. It does not tolerate wet feet for any length of time. Mulching around the tree out to the drip line helps keep temperatures lower and conserves moisture for the plant. Do not let any mulch touch the actual trunk of the tree, though.
If you live where the winter temperatures get below -10 degrees, be sure to mulch around the tree to protect it from the cold. Rose of Sharon likes heat.
Every winter or early spring, prune away last year’s growth to encourage as many blooms as possible. Since rose of Sharon can be propagated by cuttings, save the pruned off bits to start another plant. You should take only the ones that are around five inches long, dip one end in rooting solution, then plant and keep moist. Eventually, the sticks will develop roots and you can plant them where you want them.
You can also plant rose of Sharon from seed. Let the flowers stay on the bush and produce the bean shaped pod. When they are dry, harvest them and get the seeds. You can either direct sow your seeds in the spring, or start them six to eight weeks before the last frost and grow them until it is safe to transplant them.
The rose of Sharon thrives best under benign neglect. Do not fertilize it or you can cause the buds to drop. You can spread compost around the tree extending out to the dripline to give it naturally slow release fertilizer that will not burn the plant.
Japanese beetles, aphids, and spider mites love the rose of Sharon. The aphids and Japanese beetles can be killed with a dusting of Sevin dust. The spider mites must be treated with a mitecide, not an insecticide.
The rose of Sharon is also vulnerable to leaf spot, blight, and cankers. If your buds drop off, you are over or under watering your plant. You want to water it one inch a week and do so all at once. This helps the tree develop strong roots.