Propagating Salad Burnet by Division, Seed and Self-Sown Seedlings

Division: the fastest route to a cropping plant

A salad burnet clump that has been in the ground three or four years develops a woody, bare center with the living growth pushed out to a ring around the edge. That is the signal to divide, and it is both propagation and rejuvenation in one operation. A divided plant crops the same season; a seedling takes most of a year.

Divide in early spring, just as new growth is starting and before the plant begins flowering. Late summer is an acceptable second window in mild areas, provided the divisions have six weeks of growing weather to root before hard frost. Do not divide in midsummer heat and do not divide in the depths of winter.

Lift the whole clump with a fork, working well outside the rosette so you keep as much of the taproot and its side roots as possible. Shake off enough soil to see the crown, then cut down through it with a sharp knife or an old bread knife. Aim for pieces about the size of your fist, each with several growing points and a decent length of root. Throw the woody center away; it will never crop properly again.

Replant immediately at the same depth, with the crown level with the soil surface rather than buried, and water in well. Trim the leaves back by about half on each division to reduce water loss while the roots recover. Expect four to six weeks before the piece starts producing properly, and do not pick from it until it does.

Saving and sowing your own seed

Salad burnet is wind-pollinated and the flower heads are odd-looking things: tight rounded green knobs held on tall wiry stems, with the upper flowers showing feathery crimson stigmas and the lower ones dangling stamens. Leave a few heads on one plant only, at the back of the group, and cut every stem off the others so the crop is unaffected.

The seed is ripe when the head has gone brown and dry and the individual units rub off easily under the thumb. Cut the whole stem, drop it head-first into a paper bag, and hang it somewhere dry for a fortnight. Then rub the heads between your palms and pick out the seed: hard, four-angled, corky husks about an eighth of an inch (3 mm) across, easy to see and easy to handle.

Store dry, cool and dark. Fresh seed germinates well, viability falls off noticeably after two years, so sow generously from the current year's collection rather than hoarding it. Sowing is exactly as for bought seed, a quarter of an inch (6 mm) deep into cool soil in spring or late summer, and germination takes eight to fourteen days at around 60F (16C).

Because plants are wind-pollinated and cross freely, seedlings vary a little in leaf size and vigor. Watch them through their first year and keep the ones that stay compact, produce plenty of central leaves and are slow to throw flower stems. That simple selection, repeated over a few seasons, gives you a strain that suits your garden better than anything you buy.

Working with the seedlings it gives you for nothing

Left to itself on dry, free-draining, chalky ground, salad burnet self-seeds enthusiastically. Seedlings turn up in gravel paths, between paving, along bed edges and in any thin, poor patch nearby. This is a genuine nuisance if you do not want it and the easiest propagation in the garden if you do.

The seedlings are simple to recognize once you know them: a small rosette of pinnate leaves, each with paired rounded leaflets and neat saw-toothed edges, and a distinct cucumber smell when you crush one. Smelling a seedling is the quickest way to tell it from a weed before you hoe it off.

Move them young. A seedling with three or four true leaves lifts with its taproot intact and transplants without checking at all. Once it is bigger the taproot has gone down several inches and any move sets the plant back for weeks. Lift with a trowel, taking a good plug of soil, replant at the same depth, water in and keep it just moist for the first fortnight.

To stop the self-seeding rather than use it, simply keep cutting the flower stems out at the crown, which you should be doing for leaf quality anyway. A plant that never flowers never seeds, and the whole question disappears.

1. Lift and split an old clump In early spring, fork up the whole plant, cut the crown into fist-sized pieces each with roots and growing points, and discard the woody center.
2. Replant and trim Set divisions at the original depth with the crown at soil level, twelve to fifteen inches (30 to 38 cm) apart, cut the foliage back by half and water in thoroughly.
3. Collect seed from one plant only Leave two or three heads to go brown on a single plant at the back, bag the stems, dry for two weeks and rub the seed out.
4. Pot or move volunteers early Transplant self-sown seedlings while they have only three or four true leaves, before the taproot sets, and water them for the first fortnight.

Salad burnet does not root from cuttings in any reliable way. It has no creeping stems and no runners, so division, seed and volunteers are the only three routes worth your time.

Keeping track so the stock does not run down

A salad burnet clump is productive for three or four years and then declines whether or not you notice. The way to avoid a sudden gap is to stagger the plants: divide or sow one part of the group each spring so you always have plants at different ages rather than a whole bed peaking and failing together.

That only works if you know how old each plant is, so keep a simple note: the position of each clump, the year it was sown or divided, and where any divisions from it were planted. Add the date you collected seed and the year it was harvested, since two-year-old seed germinates noticeably worse and you want to know which packet is which.

One more entry pays for itself: which seedlings you kept and why. A plant that held off flowering a fortnight longer than its neighbors is worth propagating from, and next spring you will not remember which one it was.