Gadenin日本語Get the appTake softwood cuttings early in the season
The best cutting material is this year's growth taken while it is still flexible but no longer floppy: bend a shoot and it should curve well before it snaps. That stage arrives in late spring to early summer, roughly six to eight weeks after growth starts. Wood taken later has hardened and roots slowly, and wood taken too early collapses before it roots.
Choose non-flowering shoots. A shoot carrying a flower head is spending its energy on the flower, and the cutting rots more often than it roots. Look at the lower, shaded part of the shrub, where the shoots that never flowered are, and take from there.
Cut in the early morning while the shoot is full of water, and get the material into a plastic bag out of the sun immediately. A hydrangea cutting that wilts before you have prepared it has already lost most of its chances.
- Cut a four to six inch shoot Take four to six inches (10 to 15 cm) from the tip of a non-flowering shoot, cutting just above a pair of leaves on the parent plant so the stump does not die back.
- Trim to just below a node Recut the base with a clean blade a quarter of an inch (5 mm) below a leaf joint. Roots form fastest at the node, and a long stub of stem below it simply rots.
- Strip the lower leaves Remove all leaves except the top pair. Any leaf that touches the compost will rot and take the cutting with it. Keep the two top leaves; the cutting needs them to make roots.
- Halve the remaining leaves Cut the two remaining leaves across the middle with scissors. Hydrangea leaves are huge and lose water faster than a rootless stem can replace it. Halving them roughly doubles the survival rate.
- Dip and insert Dip the base in rooting hormone, tap off the excess, and push it about an inch and a half (4 cm) into moist, gritty potting mix. Firm gently so the base is in contact with the medium.
- Cover and shade Cover with a clear bag or propagator lid held clear of the leaves, and stand it in bright shade at around 68F (20C). Direct sun under a bag will cook the cuttings within an hour.
Vent the cover for a few minutes every couple of days to let the air change. Condensation running down the inside is fine; standing water in the tray is not, and is the usual cause of blackened stems.
Layering: the method that almost never fails
If the shrub has any branch low enough to reach the ground, layering is easier than cuttings and needs no propagator, no hormone and almost no attention. The branch stays attached to the parent and keeps being fed while it roots, so there is nothing to wilt and nothing to rot.
Do it in spring or early summer, once the wood has firmed slightly. Choose a flexible outer branch, bend it down to the soil, and find the point about a foot (30 cm) back from the tip where it naturally touches. That contact point is where the roots will form.
Scrape a shallow wound an inch (2.5 cm) long on the underside of the stem at that point, pin it into a shallow depression with a wire staple or a stone, and cover it with two inches (5 cm) of soil. Keep the tip of the branch above ground, and keep the buried patch moist through the summer. By the following spring it will have rooted and can be severed from the parent and lifted.
| Method | Best time | Ready to plant out | Difficulty |
|---|---|---|---|
| Softwood cutting | Late spring to early summer | Following spring | Moderate |
| Semi-ripe cutting | Late summer | Following early summer | Moderate |
| Layering | Spring or early summer | Following spring | Very easy |
| Division of a suckering clump | Dormant season | Immediately | Easy but only for suckering kinds |
The first weeks after rooting
Cuttings usually root in three to six weeks. Test by tugging one very gently; resistance means roots. Do not pull them out to check, because a cutting that has just started rooting will be set back weeks by the disturbance.
Once rooted, wean them off the humidity gradually. Open the cover a little more each day for a week or so before removing it entirely. A cutting taken straight from a closed propagator into open air will collapse within hours, having grown leaves adapted to saturated air.
Pot up individually into a free-draining compost once roots show at the drainage holes, and keep the young plants in a sheltered, shaded spot for their first winter. They are far more frost-tender than the parent shrub. In a cold climate, overwinter the pots in an unheated shed or frame rather than trusting them outside.
Do not feed a newly rooted cutting for the first month. The root system is tiny and fertilizer salts scorch it. Wait until you can see fresh leaf growth, then start with a quarter-strength liquid feed.
Why seed is not worth it, and what to log
Hydrangeas do set viable seed, but seedlings do not resemble the parent. Flower head shape, color behavior and vigor all scatter, and you wait three to four years to find out what you got. For a garden shrub you want a copy, and only cuttings or layering give you one.
Keep a simple record of every batch: the date you took the cuttings, which shrub they came from, how many you stuck and how many rooted. After two seasons that record tells you the exact week in your own garden when cuttings take best, which is more useful than any general rule about late spring.