Cut hibiscus correctly – instructions and timing

Hibiscus rosa-sinensis, marshmallow, Chinese rose mallow, indoor hibiscus or China rose is one of our most popular ornamental plants. It is actually called Hibiscus x rosa-sinensis because it is a cross between different hibiscus species.

This hibiscus blooms indoors in spurts almost all year round and, as a permanent bloomer, beautifies balconies and terraces from summer to autumn. This is the hibiscus that can be seen most often in the flower trade, it is grown in an incredible number of varieties and is available in white, yellow, orange, all shades of red, with colored accents in the flower and with double flowers.

Prune Hibiscus rosa-sinensis

With a good supply of nutrients, Hibiscus rosa-sinensis will eventually grow vigorously and grow in spurts throughout the growing season. This growth is then steered in the right direction by pruning:

• The hibiscus can always be cut back after a flowering period
• In other words, in autumn, this promotes the chance for lush new growth
• You should always cut down to the old wood
• The “internal framework” should remain as compact as possible
• The hibiscus only flowers on its new shoots
• The main cut follows in early spring, just before budding begins
• The hibiscus is severely shortened to the size of a hand, if necessary also thinned out
• If never cut, the hibiscus will grow nice and tall over time
• The new shoots with the flowers are literally becoming more and more of a “marginal phenomenon”
• At some point, the flowers would sit very far out, but then the joy of blooming also diminished
• The way to care for the flowers has just become very long …
• Also, buds that are far apart will look like fewer buds
• If you don’t like that or if the hibiscus is getting too big, a radical rejuvenation cut is due

How much you cut back at the beginning depends very much on the individual specimen. You sometimes have to wait years for a hibiscus to really start growing. The H. rosa-sinensis are cultivated using growth regulators. If a hibiscus has been given a lot of growth regulators, it will take a long time to overcome the crushing effect and return to natural growth.

The new hibiscus star: garden hibiscus

The Hibiscus syriacus, garden hibiscus, shrub marshmallow, rose marshmallow is enjoying increasing popularity in German gardens. This is not surprising, since the Hibiscus syriacus is a very attractive flowering shrub and the only representative of the genus that can overwinter outside in Germany.

Not in the last cold hole, and only in a sunny, warm location with a favorable microclimate, abundant flowers appear. The young plant needs winter protection; the adult hibiscus becomes a real, hardy garden hibiscus. It blooms in white, pink, red, burgundy, violet and must be accompanied by pruning so that it does this for many years:

1. The young hibiscus gets a grooming pruning, even if you plan to basically let it grow freely. Which is definitely good for him, as you can see here www.baumarten.net/baeume/straucheibisch.shtml.

In order for it to grow in such a pleasing shape, the young hibiscus needs some stimulation: If you cut back the young plants every spring, you encourage branching from the base. The first cut can be made immediately after planting, carefully, but you can remove any weak and damaged shoots.

2. Older hibiscus get a maintenance cut every early spring , during which the crown can be carefully shaped. All weak, thin or withered shoots are also removed. Thin but well-placed and viable shoots can be trimmed down to a few buds.

Furthermore, the maintenance cut is ongoing pruning care: If the hibiscus grows stronger on one side or otherwise irregularly, the corresponding shoots are shortened to the next side branch that grows well or – if there isn’t one – eradicated right at the base.

3. A targeted pruning of the flowers can support the rich flowering even more: If you shorten the one-year shoots by about a third in late winter, you can increase the number of flowers considerably.

At the same time, it is thinned out, since the bush becomes more and more dense due to pruning of this kind, otherwise there will be a lack of light inside the bush over time.

4. A rejuvenation cut is recommended for any hibiscus that has not been pruned for a long time, and it also offers a correction option if the hibiscus was allowed to develop unchecked on one side.

They first remove all dead or visibly over-aged shoots, then resolutely trim the rest. Only a third of the branch mass remains, even inside the bush, so your hibiscus can breathe again and sprout anew.

However, you should not give the hibiscus an “upside-down pot cut ”, but make sure it has a pleasing basic shape – consisting of a central shoot that protrudes slightly over the side branches and branches at regular “tier” intervals.

However, an annual trimming of the young H. syriacus is not absolutely necessary, if you want you can let it grow completely freely for a while. Only when it is older is it advisable to cut back the long shoots vigorously in late winter, then the hibiscus will produce more flowers again in spring. It is enough if you leave two to three eyes on each last year’s shoot.

The following applies to all garden hibiscus: If shoots freeze in heavy frost, they are cut away in the spring when pruning back into the fresh wood to prevent rot.

Grow your own hibiscus standard

The hibiscus is often cultivated as a standard, and you can grow such a standard yourself with targeted pruning measures. However, you need a little patience, it takes several years for this growth habit to develop.

How to proceed:

• Transplant young Hibiscus into its final pot and let it rest for a while
• Cut all branches of the still young plant to two or three buds
• If the main stem is well developed (take care when buying), leave it untrimmed
• It is said to grow taller and in subsequent years will be limited to 5 shoots with a bud each February
• The remaining side branches can be decimated to a bud
• If the main trunk shoots to the sides, these shoots are cut in between
• If all goes well, the main trunk will eventually have reached the desired height
• Now the base of the crown is expanded from the 5 strong shoots to the crown
• The trunk extension is shortened, the shoots on the crown branches are carefully shaped
• They should branch out, but not indiscriminately, always keeping a few shoots with individual buds
• These shoots are meant to grow strong and then branch further into an evenly branched crown
• Removing stem shoots and shaping the crown is part of the constant maintenance of the standard tree

The whole variety of hibiscus and their pruning

There isn’t just one hibiscus, although you might get that impression when you shop around in florists or garden discounters at the start of the season – Hibiscus rosa-sinensis and its hybrids were e.g. B. proclaimed by a producer association for consumer brands as the houseplant of May 2015, with a corresponding abundance of hibiscus in the shops.

Measured against this mass of hybrids, the garden hibiscus almost seems like a rare exotic, while the genus Hibiscus includes around 300 species (between 150 and 500).

In the age of the internet, (room) gardeners are discovering more and more types of hibiscus that can be ordered from specialized dealers or via file-sharing platforms. Then the following often happens: Plant comes without detailed instructions, because it is assumed that you are one of the specialists who can see by the tip of the nose (tip of the leaf) of a hibiscus which growth group it belongs to. If you are just discovering the extensive variety of hibiscus, this is not necessarily the case, so here is a small hibiscus sorting:

Hibiscus x rosa-sinensis and relatives

The Hibiscus x rosa-sinensis pruning described above also fits its relatives or ancestors, with slight differences in the pruning intensity required:

• Hibiscus arnottianus: One of the ancestors of the modern Hibiscus x rosa-sinensis. In its native Hawaii it grows into trees, with us in the right environment also quite vigorously, it must/can be pruned intensively on a regular basis.
• Hibiscus asplenum is an original relative of rosa-sinensis, which (usually uncompressed) grows sparsely, i.e. forms side shoots. Vigor normal, pruning like H. rosa-sinensis.
• Hibiscus baptistii: graceful growth, slender branches, little pruning.
• Hibiscus cooperii: Is pruned as little as possible because the white or red variegated leaves and partly reddish stems are almost more attractive than the relatively small flowers.
• Hibiscus El Capitolio needs regular pruning for strong stems, because it has to carry a multi-flowering, also fast-growing.
• Hibiscus schizopetalus needs a lot of heat, sun and fertiliser, so if it shows strong growth, you should still be careful when pruning the delicate plant.
• Hibiscus storckii grows rather dainty and is pruned normally

The wild, original hibiscus species

There is a very interesting range of wild hibiscus species that are attracting more and more interest these days: an increasing number of people only want to cultivate ‘real plants’ that have not been treated with growth hormones. This is especially true for hibiscus, the flowers of which (all) can be used as tea or edible decoration if they have not been treated with hormones, pesticides or shine spray. The wild hibiscus are quite different in growth and need different pruning care:

• Hibiscus acetosella, False Roselle, grows unpruned with a dominant main stem (high stem candidate), but can be encouraged to branch by pruning. Flowers in late autumn/early winter, main cut next summer.
• Hibiscus burtt-davyi, is said to grow like a tree by itself, regular pruning encourages the abundant appearance of the orange-pink tiered flowers.
• Hibiscus coccineus, perennial hibiscus that feeds over the winter. There is therefore no pruning, only the dead shoots are cleaned out.
• Hibiscus diversifolius grows shrubby and quite vigorous, needs space and regular pruning.
• Hibiscus laevis oh H. militaris dies in winter and does not need pruning.
• Hibiscus ludwigii grows like a shrub and is pruned like a garden hibiscus, but does not tolerate sub-zero temperatures.
• Hibiscus moscheutus can be grown in the garden and grows like a perennial, so dies down in winter and doesn’t need pruning.
• Hibiscus mutabilis from Asia presents flowers that change color throughout the day, grows very slowly and needs little pruning.
• Hibiscus paramutabilis like this, the flowers just don’t change colour, both “..mutabilis” tolerate cold temperatures down to -15 °C as adult plants.
• Hibiscus pedunculatus flowers in the year of sowing and is pruned for the first time after this flowering.
• Hibiscus radiatus can be trained to compact growth in USDA zone 10-11 (Germany: 5b-8b) by pruning at the top. In our country it survives only one garden season anyway, cultivation in the tub is not proven.
• Hibiscus sabdariffa, Roselle, short-lived, value-added hibiscus (pods taste like cranberries), USDA Zone 7+ can be gardened, pruned at harvest.
• Hibiscus taiwaniana see H. mutabilis.
• Hibiscus tiliaceus, linden-leaved hibiscus, can easily be grown from seed to a meter-high tree, which unfortunately only blooms in our heated greenhouse and is pruned there like a garden hibiscus.
• Hibiscus trionum, hour flower, self-seeding small hibiscus, the seeds even survive cold frosts, the plant itself is short-lived, does not need pruning.

Conclusion
There’s no problem pruning a hibiscus if it’s a naturally growing hibiscus (and you know what kind of naturally growing hibiscus). Surprises can only lurk in the Hibiscus-rosa-sinensis hybrids sold in mass trade – if they got a lot of growth hormones “in their youth”, you hardly need to prune them for years and then you suddenly have a vigorously growing hibiscus in front of you.