Gadenin日本語Get the appThe shape of the year
Mitsuba is a perennial, so the calendar is not a sowing-to-harvest line but a repeating cycle. Growth comes in two waves — a strong one in spring and a better one in autumn — separated by a summer stall when the plant tries to flower and largely stops making usable leaves. Winter is dormancy in cold gardens and a slow trickle of harvest in mild ones.
Once you see the year that way, the work sorts itself out. Spring is about feeding the flush and deciding which plants you will let flower. Summer is about keeping plants alive and cool rather than cropping them. Autumn is the main harvest and the time to sow if you are starting a new patch. Winter is tidying and protecting.
Nothing here is tied to a calendar date, because the trigger is always the weather rather than the month. Work from soil temperature, from your last and first frosts, and from what the plants are actually doing.
Spring: the first flush
Growth restarts as soil temperatures climb past about 45F (7C). Before it does, pull back last year's mulch, clear off any dead foliage, top-dress the bed with an inch (2.5 cm) of compost or leaf mold, and put the mulch back leaving a clear inch around each crown. That is nearly all the feeding an established patch needs for the year.
Autumn-sown seedlings that overwintered will now be well ahead of anything you sow in spring, and they are the first thing you cut. Established crowns follow within a couple of weeks. Start harvesting once a plant carries eight or ten stems, taking the outer third at a time.
Spring is also the window for lifting and dividing. Crowns in their fourth year, or any plant throwing noticeably thinner stems than its neighbors, should be lifted just as growth begins, split into pieces each with roots and two or three growing points, and replanted at the same depth with a good watering.
- Early spring: clear and mulch Remove dead top growth, top-dress with an inch (2.5 cm) of compost or leaf mold, and replace the mulch keeping it an inch clear of each crown.
- Early spring: divide old crowns Lift any plant entering its fourth year, split it into pieces with roots and two or three shoots each, and replant at the original depth. Water in well.
- Mid spring: first cuts Start taking the outer third of stems once a plant has eight or ten of them at six inches (15 cm) or more. Feed at half strength after each cut.
- Mid spring: sow a new patch if needed Surface-sow once soil sits at 55 to 68F (13 to 20C), in bright shade, and keep the surface damp for a full month.
- Late spring: choose your seeders Mark two or three plants to flower and self-seed. Cut the rising flower stems out of all the others at the base to keep them producing leaf.
Summer: hold, do not harvest
Once days run above 85F (29C) growth largely stops. Plants push up ridged flower stems, leaves toughen, and anything you cut regrows slowly if at all. Cutting hard now is how people lose established crowns, so ease right off and take only what you need for a meal.
The job through summer is keeping the root run cool and damp. Water thoroughly rather than lightly whenever the soil is dry an inch (2.5 cm) down, keep the mulch topped up, and add shade cloth if the canopy over the bed is thinner than you thought. Plants under a tree often need more water in summer, not less, because the tree takes it first.
This is also when the marked seed plants do their work — small white umbels, then green seed heads that darken as they ripen. Leave them to shed where you want seedlings, or cut the heads as they brown, dry them in a paper bag and sow the seed fresh in autumn.
| Season | Main jobs | Harvest |
|---|---|---|
| Early spring | Clear dead growth, top-dress, mulch, divide old crowns | First cuts from overwintered seedlings |
| Mid to late spring | Sow new patches, remove flower stems, feed after cutting | Main spring flush, cut every few days |
| Summer | Water deeply, keep mulch topped up, add shade if needed | Occasional stems only; growth stalls above 85F (29C) |
| Late summer | Collect or let seed drop from marked plants | Light picking as temperatures ease |
| Autumn | Sow 6 to 8 weeks before first hard frost, thin seedlings | Best crop of the year |
| Winter | Mulch crowns, cloche for winter picking, do not dig the bed | Occasional stems in mild spells or under cover |
Autumn and winter: the best crop, then rest
As nights cool the plants come back into growth, and this second flush is the one worth planning around. The stems are more tender than the spring crop and the aroma is stronger. Harvest freely now — the plant has the whole cool season ahead of it and will keep replacing what you take until frost.
Autumn is the best sowing window as well. Sow six to eight weeks before your first hard frost so seedlings reach three or four true leaves, and they will overwinter and give you your earliest crop next spring. Thin them before the cold sets in so no seedling is sitting in a damp huddle through winter.
After the first hard frost, top growth collapses in cold gardens. Cut the dead foliage away, put a two-inch (5 cm) mulch of leaves or straw over the crowns, and leave the bed alone — do not dig it, because both the crowns and this year's volunteer seedlings are in the top few inches. A cloche or low tunnel over part of the patch will keep a few stems coming through most of the winter.
Write down the date of the first spring cut, the date growth stalls in summer, the date the autumn flush starts and the date of your first hard frost. Four dates a year, and after two seasons you have a calendar for your own garden that beats any general one — you will know exactly when to sow, when to stop cutting and when to get the cloche out.
Established crowns are hardy well below zero in the ground, so winter losses are almost always wet rather than cold. If your bed lies wet, the useful winter job is improving drainage, not adding more cover.