Gadenin日本語Get the appWhy division, and why every third year
Asatsuki is a chives-type bunching allium (Allium schoenoprasum var. foliosum) that multiplies underground on its own. Each bulb splits into two or three over a season, so a station planted with three bulbs holds twenty or more after three years. That crowding is exactly what makes the plant productive at first and exactly what strangles it later.
By the third or fourth year the center of the clump gets woody, the leaves there come up short and pale, and the whole thing crops less even under a good feeding regime. Division is the cure and it is not optional maintenance; a clump left undivided for six years is a fraction as productive as one split on schedule. It is also how you turn one bought bag of bulbs into a permanent supply without buying again.
A clump due for division looks obvious once you know the sign: a ring of decent leaves around a bare or stunted middle. Do not try to feed your way past it.
When to divide
The best window is early autumn, when the summer dormancy is ending and the bulbs are plump but have not yet pushed their autumn leaves. Divisions made then root strongly in warm soil and are fully established before winter. Early spring, just as the first shoots appear, is the second-best option and the right call where winters are severe.
Do not divide in the middle of the summer dormancy in hot dry soil, and do not divide during the flowering push in early summer. In both cases the bulbs have no capacity to root out and losses run high.
| Timing | Suitability | Notes |
|---|---|---|
| Early autumn, as heat eases | Best | Bulbs plump, soil warm and damp, roots out before winter |
| Early spring, at first shoots | Good | Safest in cold-winter areas. Cut leaves back to 2 inches (5 cm) |
| Early summer, flowering | Poor | Energy is in the flower stalks. Heavy setback |
| Midsummer, deep dormancy | Poor | Hot dry soil, no root activity, high rot risk |
Dividing a clump, step by step
The job takes minutes per clump and the main risk is letting the bulbs dry out between lifting and replanting. Have the new positions prepared and watered before you lift anything, and work on no more clumps at a time than you can replant within the hour.
- Cut the leaves back first Shear the clump to about two inches (5 cm). This makes the bulbs visible, cuts water loss while they are out of the ground, and stops you fighting a mass of foliage. In autumn there may be little foliage to remove anyway.
- Lift the whole clump with a fork Push a fork in four to six inches (10 to 15 cm) out from the edge of the clump on three or four sides and lever gently until the whole mass lifts. Do not pull the clump up by the leaves; the bulbs separate and stay in the ground.
- Shake off soil and pull it apart by hand Loosen the soil from the roots and work your thumbs into the mass. Healthy bulbs come apart with light pressure along their natural joins. Use a knife only on a woody old core that will not yield.
- Sort into groups of three or four bulbs Each division should have three or four firm bulbs with roots attached. Single bulbs will grow but take an extra season to become a cuttable clump. Discard soft bulbs, the woody dead center, and anything with mold at the neck.
- Replant at once, one inch deep Set each division with the bulb tips about an inch (2.5 cm) below the surface, six to eight inches (15 to 20 cm) between stations. Firm lightly and water in thoroughly. If you cannot replant immediately, keep the divisions in damp compost in the shade for a day at most.
Expect new leaves in two to three weeks in autumn. Do not cut anything from a fresh division for at least eight weeks; it is rebuilding roots, not making a crop.
Growing from seed
Seed is the slow route but it is how you build a large planting cheaply. Sow in modules in spring at 60 to 70F (15 to 21C) and expect fourteen to twenty-one days to emerge, each seedling appearing as a bent thread with the seed coat stuck to the tip. Keep the surface continuously damp for the whole of that window; one dry afternoon at day eight kills seed that was about to appear.
Sow eight to twelve seeds into each module and never thin them. A single seedling is a single hair and is useless on its own; the point is to plant the whole cluster out as one clump. Plant out when the cluster is four to five inches (10 to 13 cm) tall, spaced six to eight inches (15 to 20 cm) apart. Take no harvest in the first year. Seed also loses viability fast, so a packet more than two years old germinates thinly and unevenly. If a sowing comes up in patches with bare gaps, suspect the age of the seed first.
Choosing what to keep, and recording it
Division is selection whether you think about it or not. Every time you split a clump, keep the divisions from the plants that gave you the thickest leaves, resisted rust best, and came back earliest in spring, and compost the weak material rather than replanting it out of thrift. Over four or five rounds this measurably improves the strain in your own ground.
Note the date each station was divided, how many divisions came off it, and where each one went. Without that record you will not know two years later which clumps are three years old and due, which is why so many gardens end up with everything congested at once. Also record how long each division took to produce its first cuttable leaves; that number tells you how far ahead of demand you need to divide.