Gadenin日本語Get the appRoot cuttings are the standard method
Angelica tree propagates from root cuttings more readily than almost anything else in a temperate garden, which is exactly why it suckers so aggressively in the first place. Any severed section of root of pencil thickness or better, left in contact with soil, is likely to throw a shoot. This makes deliberate propagation almost trivially easy and also explains why careless digging around an established clump produces a scatter of new plants.
Take the cuttings while the plant is fully dormant in the middle of winter, when the roots are loaded with stored reserves. Work back from the edge of the clump rather than digging into the crown; you want roots running outward at a depth of four to eight inches (10 to 20 cm), not the woody base of the plant.
- Expose an outward-running root Dig a trench a couple of feet (60 cm) out from the clump and follow a root back toward the plant. Aim for root at least as thick as a pencil; thin fibrous root rarely produces a shoot.
- Cut sections and keep track of which end is which Cut sections two to four inches (5 to 10 cm) long. Cut the end nearest the parent plant square and the far end at a slant. Planted upside down a root cutting will usually fail, and after ten minutes on the bench you cannot tell the ends apart without the convention.
- Insert vertically into free-draining compost Push each section square end up into a pot of gritty potting mix so the top is level with the surface, then cover with a quarter-inch (5 mm) of grit. Alternatively lay sections horizontally an inch (2.5 cm) deep, which works nearly as well and removes the orientation problem.
- Keep cool, barely moist and out of direct sun A cold frame or an unheated greenhouse is ideal. The cuttings need cold and patience, not warmth. Water only enough to stop the compost drying out; wet compost rots the sections.
- Wait for shoots in spring, and do not repot early Shoots appear in spring, typically six to ten weeks after the cuttings were taken, but roots form after the shoot rather than before it. Leave the cutting undisturbed until you see roots at the drainage holes, usually by midsummer, before potting up.
Lifting suckers is quicker still
If a clump is established, the easiest new plants are the suckers you were going to remove anyway. A sucker a foot or two (30 to 60 cm) tall, standing a good distance from the parent, will usually have made some root of its own. Lift it in winter while dormant: dig around it in a circle a foot (30 cm) across, then follow the connecting root back toward the parent and sever it with a spade, keeping as much of the connecting root with the sucker as you can.
Success is much higher on suckers in their second year than on this season's growth, because the first-year ones are often still living entirely off the parent's root and have almost no roots of their own. If a lifted sucker comes up with no fibrous root at all, treat what you have as a root cutting rather than a plant: cut the top off, lay the root section in a pot, and let it start again.
| Method | When | Time to a usable plant | Reliability |
|---|---|---|---|
| Root cuttings | Midwinter, fully dormant | One full season to pot on, two to plant out | High. The default method |
| Lifting second-year suckers | Winter, dormant | Often plantable immediately | High if roots come with it |
| Lifting first-year suckers | Winter, dormant | One season in a pot | Moderate. Usually rootless |
| Seed | Sown after cold stratification | Two to three years | Slow and uneven. Rarely worth it |
| Stem cuttings | Not recommended | - | Poor. The wood does not root readily |
Every root fragment you leave behind when lifting a sucker is itself a potential new plant. If you are trying to restrict the patch as well as propagate from it, sieve the disturbed soil and remove the pieces rather than forking them back in.
Seed is possible but slow
Mature plants carry large sprays of small cream flowers in late summer, followed by dark berries. The seed germinates, but it needs a period of cold moist stratification of two to three months to break dormancy, germination is uneven across a couple of seasons, and seedlings take two to three years to reach a size worth planting out. Given how easily root cuttings work there is little reason to bother unless you specifically want genetic variation.
There is also a containment argument against letting the plant seed at all. Birds take the berries and carry seed well beyond your garden, which is one of the routes by which this species has spread into wild ground. Where the plant is a listed invasive, cutting the flower heads off before the berries ripen is the responsible baseline, and it costs you nothing since the shoots are the crop.
Forcing cut stems indoors
This is the trick worth knowing. Stems cut in late winter, while fully dormant but after they have had their winter chilling, will break their terminal buds indoors in nothing but water. It gives you a crop of shoots weeks ahead of the garden and it makes productive use of stems you were removing anyway during winter thinning.
Cut stems about two to three feet (60 to 90 cm) long, with a fat, healthy terminal bud, and take them from stems you have already decided to remove. Stand them in a jar with three or four inches (8 to 10 cm) of water in a bright room at normal indoor temperature, around 60 to 68F (15 to 20C). Change the water every couple of days and recut the base by half an inch (1 cm) each time, or the cut ends foul and the buds abort.
Buds usually break within one to three weeks and are ready to cut once the shoot reaches four inches (10 cm) with the leaflets still folded, exactly as in the garden. The stem gives you one bud and then it is spent; put it out for disposal afterwards, and remember that a forced stem is dead wood, not a cutting to be planted.
Force only stems you are culling. Cutting sound stems off a healthy clump in winter to force indoors costs you the same buds you would have harvested outside in spring, plus the stem itself.