Gadenin日本語Get the appChoose the method by habit
Both habits root readily, but the sensible route differs. Creeping types propagate themselves and mostly need you to move the results. Tall types are best taken as stem cuttings, and conveniently the cuttings are exactly the material you remove when you cut the clump back in early summer to stop it flopping. One job supplies the other.
| Method | Best for | When | Time to root |
|---|---|---|---|
| Stem cuttings | Tall upright types | Early summer, before flower buds form | Two to three weeks |
| Broken pieces pushed into soil | Creeping mat types | Any time in the growing season | One to two weeks |
| Single fallen leaves | Fleshy-leaved creeping types | Spring to late summer | Three to six weeks to a visible plantlet |
| Division of the crown | Tall upright types | Early spring as shoots appear | Immediate, it is a plant already |
| Seed | Species only, not named plants | Spring, surface sown | Slow, and offspring vary |
Stem cuttings from the tall types
Take these in early summer, when the stems are firm but have not started to form buds. A cutting taken after flowering starts will root, but it wastes the plant's energy and gives a weaker result.
- Cut a shoot three to five inches long Take the top three to five inches (8 to 12 cm) of a healthy stem with a clean blade, cutting just above a leaf joint on the parent so the parent branches from that point.
- Strip the lower leaves Pull off the leaves from the bottom third to leave a clean length of stem. Buried leaves rot and take the cutting with them.
- Let the cut dry Stand the cuttings somewhere shaded and airy for one to three days until the cut end forms a dry skin. This one step prevents most rot, and skipping it is the usual reason cuttings fail.
- Insert into gritty mix Push each cutting an inch (2 to 3 cm) into equal parts compost and coarse grit. Firm just enough to hold it upright. Several cuttings fit around the edge of one small pot.
- Keep it bright, not wet Bright shade, no cover, no propagator, no misting. Water very lightly once after a week. Humidity rots succulent cuttings rather than helping them.
- Test after two to three weeks Tug gently. Resistance means roots. Pot the rooted cuttings individually and treat them as normal plants, but give them one winter in a sheltered spot before planting out.
Creeping types root from anything
There is very little to say about propagating creeping sedum except that it is nearly impossible to fail. A stem that is knocked off and lands on soil will produce roots at the leaf joints within a fortnight. Even a single fat leaf that drops onto damp grit will make a tiny plantlet from its base. This is why these types colonise gravel drives and the tops of walls without anybody planting them.
The practical version is to pull off a handful of rooted pieces from the edge of an established mat, scatter them where you want the plant, and press each one down so the underside of the stem touches soil. Sprinkle a little grit over the stems to hold them in contact. Water once, then leave them. In six weeks the patch will be knitting together.
The same trait makes creeping sedum spread where you did not intend it. When you sweep or weed near a mat, collect the broken pieces rather than leaving them lying in a border, or you will be pulling stonecrop out of your gravel for years.
Division of a tall clump
Division is the fastest way to get full-sized plants, and it is also the maintenance job that keeps a tall clump from splitting open. Do it in early spring when the fat new buds are just visible at ground level, so you can see what you are cutting.
Lift the whole clump, shake the soil off, and pull or cut it into pieces carrying three to five buds each. The outer pieces are the young, vigorous ones; the woody center has usually stopped producing good growth and should go on the compost pile. Replant at the same depth, eighteen inches (45 cm) apart, and do not water for a week.
Seed, and why you probably should not bother
Sedum seed is dust fine. Sown on the surface of a gritty mix, pressed down but not covered, and kept just moist at around 65F (18C), it germinates in two to four weeks. The seedlings are minute and take two seasons to reach any size.
The real objection is that seedlings from a garden plant will not match the parent. Leaf color, height and flower shade all vary, and any plant with a name is a selected clone that only comes true from cuttings or division. Grow from seed if you want to raise a species from a reputable source or you simply enjoy it, and use cuttings for everything else.
Keep track of what you took
Cuttings and divisions look identical once they are in pots, and by autumn you will not remember which parent gave which tray. Note the date you took them, the parent plant and its position, and the date the first ones rooted. Over two seasons this tells you the exact fortnight in early summer that works best in your garden, which is far more useful than any general rule.