The Chinese hibiscus (Hibiscus rosa-sinensis) is a very popular houseplant and is also widely grown as an outdoor shrub in the tropics and subtropics. It’s fairly easy to grow—at least as long as you can offer it full sun and good atmospheric humidity!—but it’s not that easy to propagate. Certainly, efforts to root a hibiscus tip cuttings in a glass of water—a technique I don’t recommend anyway (read Starting Cuttings in Water: Not Such a Good Idea)—are almost always unsuccessful. But if you apply a rooting hormone and slip the cuttings into a good, fairly sterile potting mix, the success rate increases enormously.
Step by Step
Here’s how to do it:
If possible, start in spring or early summer (you can also take cuttings in other seasons, but they take longer to root and the success rate decreases).
With pruning shears, cut off a section of stem tip about 3 to 5 inches (7 to 12 cm) long. Any angle cut from 45? to 90? is fine. Remove any flower buds and also the leaves at the lower end of the cutting, freeing up about 1 1/4 to 2 inches (3 to 4 cm) of bare stem.
Now, pinch the upper tip. Pinching will slow down the cutting’s green growth, thus direct more energy towards the production of new roots. It also stimulates the budding plant to produce natural rooting hormones. Also, pinching at this stage will encourage improved branching later.
Apply a rooting hormone to the cut end. You can either pour some into a dish and dip the stem in it or brush it onto the stem with a cotton swab.
Next, insert the cutting into a pot of moist potting soil, make sure that at least two nodes (former leaf junction points) are covered with potting soil, and press lightly so it stands up on its own. To save space and soil, you can put several cuttings in the same pot as long as you separate them later.
Cover the container with some sort of transparent cover (a plastic dome, a clear plastic bag, a recycled plastic pop bottle, etc.) to create a sort of mini-greenhouse that will keep the humidity extremely high and moderate temperature changes. Place the container in a warm spot (about 75–80 °F/24–27 °C) under medium light (beneath a grow light, for example), but avoid direct sunlight at this point. After all, you want to maintain good, even heat, not boil the poor cuttings!
When New Leaves Appear
When new leaves appear (and that can take between 2 weeks and 2 months depending on a whole host of factors), it’s a sign the cutting has rooted and you can start to acclimatize it to normal indoor conditions, gradually removing the mini-greenhouse covering over a 4- or 5-day period. If you planted several cuttings in the same pot, now is the time to pot them up individually.
That’s all there is to it! You’ll have a nice little hibiscus that will probably begin to bloom in a few months.
You’ll find the young plant will need to be repotted into larger and larger containers as it grows, perhaps even twice the first year. And in mild climates where Chinese hibiscus can be grown outdoors, always acclimatize it gradually to outdoor conditions before planting permanently in the garden.
To learn more about how to grow this Chinese hibiscus as a houseplant, read The Secrets to Growing a Hibiscus Indoors.