Gadenin日本語Get the appLayering: the plant does most of the work
Forsythia self-layers. Any arching stem whose tip rests on bare soil for a season will root where it touches, and by the following year you have a new plant joined to the parent by a length of old stem. Gardeners discover this by accident, usually while wondering why the shrub has appeared two feet outside its original outline. Used deliberately, it is the simplest and most reliable way to make new plants, and it needs no equipment at all.
To do it on purpose, choose a low, flexible stem from the outside of the shrub in spring or early autumn. Bend it down to the ground, scrape a shallow trench where it touches, and pin it there with a wire staple, a tent peg or a stone. Cover the pinned section with two or three inches (5 to 8 cm) of soil, leaving the last eight to twelve inches (20 to 30 cm) of the tip above ground, and keep the spot from drying out.
Rooting takes one growing season in most cases, sometimes two on a slow site. Check by tugging the tip gently in late summer or the following spring; resistance means roots. Sever the layer from the parent, leave it in place for a few more weeks to establish on its own roots, then lift it with a spade and move it. A layer transplants far better than a cutting because it arrives with a substantial root system already made.
Nicking the underside of the stem where it will be buried, a shallow slice halfway through the bark, speeds rooting and makes it more even. It is not essential with forsythia, which roots readily anyway, but it costs nothing and improves the odds on an older, stiffer stem.
Softwood and semi-ripe cuttings
Cuttings suit you better than layering when you want a lot of plants, for a screen or a boundary line, rather than one or two. Forsythia roots from soft young growth in late spring and early summer, and from firmer semi-ripe wood in mid to late summer. The soft ones root faster but wilt easily, the semi-ripe ones are slower and far more forgiving to a beginner.
Take softwood cuttings early in the morning while the shoots are full of water. Cut four to six inch (10 to 15 cm) lengths from the tips of the current season's growth, trim each just below a leaf joint, strip the lower leaves and halve any large remaining ones to cut water loss. Insert them around the edge of a pot of free-draining gritty potting mix, water, and cover with a clear bag or propagator to hold humidity. Keep them out of direct sun. Roots usually appear in three to five weeks.
Semi-ripe cuttings are taken from wood that is firm at the base and still soft at the tip. Same length, same preparation, but they cope with less humidity and can go into a shaded cold frame or a sheltered spot outdoors. Expect six to ten weeks. Rooting hormone helps a little with both types and is not the difference between success and failure with this plant.
Hardwood cuttings work too and are the least effort of all. In late autumn or early winter, cut pencil-thick lengths of the season's ripened wood eight to ten inches (20 to 25 cm) long, cut flat at the bottom and angled at the top so you can tell which way up they go, and push them two thirds of their length into a slit trench of gritty soil in a spare corner. Leave them alone for a full year. A good proportion will have rooted by the following autumn.
| Method | When to take | Time to root | Best for |
|---|---|---|---|
| Layering a low stem | Spring or early autumn | One growing season | One or two strong plants with no kit |
| Softwood cutting | Late spring to early summer | 3 to 5 weeks | Fast results if you can keep humidity up |
| Semi-ripe cutting | Mid to late summer | 6 to 10 weeks | Reliable batches in a cold frame |
| Hardwood cutting | Late autumn to early winter | About a year | Large numbers with almost no attention |
| Lifting a rooted layer | Late winter, while dormant | Immediate | Moving a self-layered shoot that already rooted |
Growing the young plants on
Rooted cuttings should stay in their pot until the roots fill it, then be potted individually and grown for a season before planting out. Do not rush a rooted cutting straight into open ground in its first autumn; it has a small root system and a dry spell or a heaving frost will kill it, whereas the same plant a year later is essentially unkillable.
Pinch the growing tip of a young plant once it has made six or eight inches (15 to 20 cm) of growth. That forces branching low down and gives you a bushy plant with several stems from the base, which is what you want in a shrub whose long-term pruning depends on renewing stems from the crown. A single-stemmed young forsythia takes years to build a proper framework.
Do not expect flowers early. A plant from a cutting typically takes two to three years to flower properly, and a layer often flowers a year sooner because it starts life larger. Both are normal and neither is a sign that the propagation failed.
- Label with the date and the method Write the date taken and whether it is softwood, semi-ripe or hardwood. Rooting times differ by weeks and unlabelled pots get abandoned too early.
- Check for roots by resistance, not by digging A gentle tug that meets resistance means roots. Tipping the pot out repeatedly breaks the fine new roots you are checking for.
- Wean gradually off humidity Once rooted, open the bag or frame for longer each day over a week or two. A cutting moved straight into open air will collapse.
- Pot up before the roots circle Move each rooted cutting into its own pot as soon as roots reach the sides. Circling roots in a small pot follow the plant into the ground.
- Overwinter somewhere sheltered Young plants in pots are far more exposed to cold at the root than the same plant in the ground. A cold frame or a wall base is enough.
Keep a note of how many cuttings you took and how many rooted, along with the date and method. Two seasons of that record tells you which method actually works in your conditions, which is worth more than any general figure.
Forcing cut branches indoors
Forsythia is the classic shrub for forcing, because the flower buds are already fully formed and simply waiting for warmth. Cut branches in late winter, bring them indoors, and they will open weeks ahead of the plant outside. It costs you nothing if you take the branches you were going to remove anyway, though remember that every stem cut is flowers you will not see on the shrub itself.
Cut stems two to three feet (60 to 90 cm) long on a mild day in late winter, choosing wood thickly studded with fat buds. Recut the base at a steep angle, split the bottom inch, and stand them in deep water in a cool room, out of direct sun and away from a radiator. Cooler conditions bring them on more slowly and the flowers last much longer. Change the water every few days.
Expect one to three weeks to open, depending on how far the winter has already progressed. Branches cut very early, soon after midwinter, take the longest and are the least reliable; the closer you get to the shrub's own flowering time outdoors, the faster and more evenly they respond. Once open, moving the vase somewhere cooler each night extends the display noticeably.
Take the forcing branches from stems you would remove anyway during renewal, or from the inside of a crowded shrub, and you get the flowers indoors without paying for them outdoors. Cutting the best-budded outer stems for the house is a straight swap, not a bonus.