Many gardeners like to cut back their garden hibiscus after it blooms in the fall. However, this is not a good idea. Read why here.
Hibiscus syriacus, also called shrub althea or garden marshmallow, grows very successfully in gardens. Once rooted, the shrub is fully hardy and, if treated properly, displays a large profusion of yellow, pink, white or purple flowers in summer. Once the plant has bloomed off in late summer, the question becomes: prune or not? Here is what you need to know about the best time to prune your garden marshmallow, and how to do it.
Pruning hibiscus in the spring
Unlike many flowering shrubs, hibiscus is not pruned in the fall, but rather in late winter or early spring. The reason for this is that the shoot ends, which may not be fully mature, serve as a buffer mass in case heavy frosts over the winter cause the plant to freeze back. Pruning also stimulates the growth of the hibiscus, and that should start in the spring if possible. So let the pruning shears stick around for a few more months without worry. In late winter, end of January/beginning of February, there is still enough time for the care. Rose mallows (Hibiscus moscheutos) are an exception. They go in late summer and are cut off near the ground in the fall.
Care pruning on the hibiscus
In principle, a hibiscus does not need to be pruned heavily at all. However, the plant tolerates shaping pruning very well and thanks the care with a vital flowering. If the crown structure is already complete, only over-aged, withered and troublesome branches need to be removed to maintain shape and flowering. Cut back the previous year’s flowering shoots significantly, so the hibiscus will be nice and dense. So that it is not too crowded, in addition, from time to time at a branching completely cut off a flowering shoot.
Rejuvenation pruning for more flowers
If a hibiscus is not pruned for a long time, only sparse flowers develop on the shoots, the plant becomes lazy in flowering. To counteract this, the hibiscus should be given a rejuvenating pruning every few years. This involves cutting off all branches at different heights.
For a beautiful crown, the outer branches should be cut shorter than the inner ones. Massive pruning in the spring is followed by very strong sprouting, which should be re-cut later in the summer. If you have done a rejuvenation pruning on your garden marshmallow, it will probably fail to bloom this year. The following year, however, you can look forward all the more to a great bloom.
How to properly overwinter hibiscus
The frost-hardy garden hibiscus can spend the winter outside without any problems. Young plants should be covered with a layer of mulch or brushwood around the roots. If the plant is in a rather drafty spot, a cover of fleece is good for surviving very cold nights. Heat-loving hibiscus species such as the China rose (Hibiscus rosa-sinensis) must be brought indoors for overwintering. It is best to place the plant in a bright place at about 15 °C / 59 °F room temperature. Suitable for this purpose, for example, a winter garden or a bright staircase. Water the plant regularly, but little, and do not fertilize. Do not be alarmed if the leaves fall in the winter quarters. A certain loss of foliage and flowers is normal after putting away and is due to the change of location and light.