How to Pinch Shiso for a Bushy Plant and a Long Picking Season

Make the first pinch at four pairs of true leaves

Left alone, shiso puts everything into one central stem, runs up to two or three feet (60 to 90 cm), and flowers at the top. You get a small number of leaves on a bare stalk and a short season. Pinch out the growing tip and the two buds sitting in the joint below it are released, so one stem becomes two.

The right moment is four pairs of true leaves, when the plant is six to eight inches (15 to 20 cm) tall. Earlier than that and the plant has not built enough root to push strong side shoots, so they come out thin and stall. Much later and the lower joints have hardened, and the buds there stay shut.

1. Count down one joint from the tip Find the topmost joint where you can see two small green buds in the leaf axils, and cut cleanly just above it. Those two buds become your new leading shoots.
2. Leave a quarter inch above the buds A quarter of an inch (5 mm) is enough to avoid nicking the buds without leaving a stub. A longer stub dies back brown and looks like disease.
3. Use scissors, not fingers Shiso stems are square and fibrous. Pulling with your fingers strips a length of skin down the stem, which dries back and can rot in wet weather. Cut horizontally with clean scissors.
4. Eat what you cut The pinched tip is the most tender and most strongly scented part of the whole plant. This is your first harvest, not a prunings pile.

For about a week after the first pinch the plant appears to have stopped. It is building the side shoots. Once they move it will outgrow an unpinched plant within a fortnight and never look back.

Each pinch roughly doubles the number of shoots

The maths is simple and it is the whole argument for the job. One pinch gives you two shoots, pinching both of those gives four, pinching those gives eight. Leaf count follows shoot count, so how much shiso you pick over a summer is essentially decided by how many times you go round the plant with scissors.

It does not multiply for ever. Once the new shoots are coming thin and the leaves noticeably smaller than the ones below, the plant has divided as far as it usefully can. From that point stop counting pinches and simply harvest from the tips, which keeps the shape without asking for more branching.

Repeat every two to three weeks

Judge the next pinch by leaf count rather than by the calendar. When the shoots from the last pinch carry three or four pairs of leaves, they are ready to be pinched in turn. In the fast growth of high summer that comes round in about two weeks; in cooler spring or autumn weather it is nearer three.

Pinching and harvesting are the same action. Cut what you need for the kitchen from the tips of the shoots rather than stripping leaves from the middle of the plant, and the plant is pinched as a side effect.

Once the days shorten, pinch out flower spikes too

Shiso is a short-day plant. It does not flower because it is old or stressed; it flowers because the nights are getting longer, and it will do that on cue in late summer regardless of how well you have grown it. The first sign is the tip leaves becoming small, narrow and crowded together, with a thin green spike pushing up between them.

Once flowering takes hold the leaves turn small, tough and much less aromatic, and the stems go woody. Pinching out every spike as it appears will not stop the process, but it will hold the plant in leaf for another three to four weeks, which is a meaningful extension at the end of the season.

1. Cut two joints below the spike Taking just the spike itself gets you a new one within days. Cutting two joints down removes the tip that is committed to flowering and forces side shoots that are still in leaf mode.
2. Go round the whole plant weekly Spikes appear on every shoot at roughly the same time. Missing a few on the shaded inside of the bush is enough to pull the whole plant towards flowering.
3. Reduce feeding as you do it High-nitrogen feed at this stage produces soft growth that goes straight to flower anyway. Ease off and let the plant coast.
4. Know when to stop fighting When new shoots are thin and the leaves are half the size they were in midsummer, accept it. Cut the whole plant, use the lot, and let a few plants flower for seed.

The flower spikes themselves are worth keeping when you cut them. Picked young, while the buds are still tightly closed and green, they carry the same scent as the leaves in concentrated form.

Rescuing a plant you never pinched

A plant that has been left to run up on a single stem is not lost, as long as there is still green growth low down. Cut it back hard, to a height that leaves three or four pairs of leaves on the stem, and dormant buds at those joints will break within ten to fourteen days. You lose about two weeks and gain a bush.

The one situation where this does not work is a stem that has gone genuinely woody and brown to the base with no green leaves left on it. Woody shiso stem rarely produces new shoots. Pull it, and sow again if there is enough season left.

Note in your records the date you made the first pinch and the date the first flower spike appeared. Compare those two dates across a couple of seasons and you will know exactly how many pinches your own summer has room for.