Gadenin日本語Get the appChoose the method by the season you are standing in
This is one of the easier woody shrubs to propagate, and there is a workable method available in almost every season. What you should not do is take cuttings from seed capsules or expect seed to reproduce the plant you like, because seedlings vary widely and rarely match the parent in flower color or form.
The table sorts the methods by when you can start them, with an honest note on how long each takes and how reliably it works.
| Method | When to start | Speed and reliability |
|---|---|---|
| Softwood cuttings | Early summer, from flexible new shoots | Roots in three to five weeks; the highest success rate |
| Semi-ripe cuttings | Late summer, from shoots firming at the base | Roots in six to eight weeks; reliable but slower |
| Hardwood cuttings | Late autumn to winter, from bare dormant wood | Roots by the following spring; slow, needs no equipment |
| Simple layering | Spring, on a low flexible branch | Rooted by the following spring; almost cannot fail |
| Removing a rooted sucker | Late winter while dormant | Immediate, but only if the plant has thrown one |
| Seed | Winter, after cold moist storage | Germinates easily but the offspring will not match the parent |
Softwood cuttings, the method that works best
Early summer is the moment. The shoots the plant has pushed since leaf-out are long enough to cut from but still soft, and they root faster than wood at any other stage. Take them first thing in the morning while the shoots are full of water, and keep them out of the sun from the second you cut them.
Pick shoots that bend without snapping and that carry no flower buds. A shoot heading into flower puts its energy into the bud rather than into roots, and it will usually rot before it strikes.
- Cut four to six inch (10 to 15 cm) tips Take the top of a non-flowering shoot with three or four leaf joints on it, cutting just below a joint with a clean blade. Drop the cuttings straight into a bag with a little water in it, and work on them within the hour.
- Strip the lower leaves and halve the upper ones Remove all leaves from the bottom half of the cutting, leaving two or three at the top, and cut those remaining leaves across by half. That reduces water loss without removing the plant's ability to feed the developing roots.
- Dip in rooting hormone and insert Dip the base in rooting powder or gel, tap off the excess, and push the cutting a third of its length into a free-draining mix of equal parts compost and perlite or sharp sand. Firm it in so the base is in contact with the mix.
- Keep the air humid and the light bright but indirect Cover the pot with a clear bag held off the leaves by canes, or use a propagator. Aim for around 70F (21C). Direct sun cooks them; deep shade starves them. Vent the cover for a few minutes daily to stop mold forming.
- Test at three weeks Give a cutting the gentlest tug. Resistance means roots. Once several are rooted, open the cover progressively over a week to harden them, then pot them up individually into ordinary potting mix.
Take twice as many cuttings as you want plants. They cost nothing, some will always fail, and a full tray is far easier to keep humid than a lone pot.
Hardwood cuttings and layering, for the patient
Hardwood cuttings need no propagator, no misting and almost no attention, which makes them the sensible option if you want a hedge's worth of plants and do not mind waiting. Take them in late autumn or winter while the shrub is bare, using pencil-thick wood from this year's growth. Cut lengths eight to ten inches (20 to 25 cm) long, with a straight cut below a bud at the base and a sloping cut above a bud at the top so you can tell which way up they go.
Push them two thirds of their length into a slit trench in a sheltered corner of the garden, or into deep pots of gritty potting mix stood outside, leaving two buds above ground. Firm them in, and leave them entirely alone. Some will push leaves in spring before they have rooted, which means nothing; do not lift them to check. Lift and pot the successes the following autumn, a full year after taking them.
Layering is the closest thing to a guaranteed result. In spring, pick a low branch flexible enough to reach the ground. Nick the underside of the bark where it will touch the soil, peg it down with a wire staple or a stone, and bury that section under three inches (8 cm) of soil, leaving the tip pointing upward and clear. Keep the spot from drying out through the summer. By the following spring it will have rooted, and you can sever it from the parent and lift it with its own root system already working.
Seed, and why the shrub does this for you already
Rose of Sharon seeds itself around freely, and most gardeners meet its seed propagation as a weeding problem rather than as a project. Every one-day flower is followed by a green capsule that dries brown, splits into five sections and scatters dozens of viable seeds. Those seeds germinate readily in bare soil, gravel and the crowns of border perennials, and one mature unattended shrub can produce hundreds of seedlings within a few yards of it.
If you actually want seedlings, collect capsules when they have turned brown but have not yet split, dry them indoors in a paper bag until they open, and store the seed cool and dry. Sow after six to eight weeks of cold, moist storage in the fridge, then keep the pots around 70F (21C). Germination is quick and the plants are easy. They flower in two to three years.
The catch is that the offspring will not match the parent. Flower color, form and the density of bloom all vary from seedling to seedling, and most are noticeably plainer than the plant they came from. If you want the plant you already have, take a cutting. Use seed only when you want a batch of tough, cheap plants for a screen and do not mind what color they turn out.
Whichever method you use, keep a note of the date you took the material, which plant it came from and how many of each batch struck. Two seasons of those figures tell you exactly which fortnight in early summer gives you the best strike rate in your own garden, and that is worth more than any general advice about timing.