Gadenin日本語Get the appThe year in outline
Lemon balm has a very predictable annual rhythm, and once you have seen a clump through one season you can anticipate the whole of the next. There are only four or five jobs in it, and their timing is set by the plant rather than by the calendar.
| Stage | What the plant is doing | What to do |
|---|---|---|
| Early spring | Shoots pushing from the crown | Clear last year's dead stems, feed lightly, divide if the center is bare |
| Mid spring | Fast leafy growth | Start picking; plant out young plants and seedlings |
| Early summer | Stems lengthening, buds forming in the leaf joints | The main cut: take the clump down by half and harvest heavily |
| Midsummer | Regrowth, or flowering if uncut | Hard cut to four inches (10 cm) for a fresh flush; deadhead anything you let flower |
| Late summer | Second flush of clean leaves | Pick freely, freeze the surplus, remove any seeding stems |
| Autumn | Growth slowing, color fading | Last light picking; divide if you did not in spring; stop hard cutting |
| Winter | Dormant, top growth dead | Cut dead stems to the base, clear the debris, keep the crown from sitting wet |
Spring: clear, feed, and divide if it needs it
As soon as the new shoots show at the crown, cut away whatever dead stems are still standing and clear the litter from around the base. This is not tidiness for its own sake: rust and leaf spot overwinter in that debris, and a clump cleaned up in spring is markedly less troubled later.
Give it one light feed and no more. This is also the moment to divide, while the shoots are a few inches high and the plant has all season to recover. If the middle of the clump was bare last year, it will be worse this year, so lift it now rather than promising yourself you will do it in autumn.
Picking can start as soon as there is enough growth to spare. Spring leaves are among the best of the year.
Early summer: the one week that matters
Watch the shoot tips from late spring. When the stems begin to run up and you can see small green buds in the leaf joints towards the top, the plant is about to flower. That is the signal, and it comes at much the same point each year in a given garden.
Cut the whole clump back by half, above a pair of leaves on each stem. This is your biggest harvest of the year and the leaves are at their most fragrant. The plant breaks into side shoots within a fortnight and gives you a second crop instead of a crop of seed.
Everything difficult about lemon balm follows from missing this week. Flowering coarsens the leaf, drops the scent, and fills the surrounding beds with seedlings that you will be pulling out for the next two springs.
Midsummer: the hard cut, and what to do about bees
By the middle of summer the regrowth starts to look dusty and tired, mildew appears on the lower leaves, and the plant makes another attempt at flowering. Take it right down to about four inches (10 cm), clear the cut material away, water it and give it a light feed as it starts to reshoot. In two to three weeks you have a clean, compact, strongly scented plant, and it will carry you to the frosts.
Bees are genuinely enthusiastic about lemon balm flowers, and there is a fair case for letting some open. Compromise: let one clump, or a few stems at the back, flower for the bees, and cut those stems the moment the petals drop and before the seed colors. You get the insects without the seedlings.
Do not make a hard cut with fewer than about six weeks of growing weather left. The plant needs to put some growth back on before it goes dormant.
Autumn and winter
Pick lightly through autumn and freeze what you can while the leaves are still good. Growth slows, the color fades, and the plant winds down; there is nothing to correct in that. Early autumn is a workable second window for division if spring got away from you, as long as the pieces have time to root before the cold.
After the first hard frosts the top growth blackens. Cut it to the base and take it away rather than leaving it as a mulch over the crown, which holds water exactly where you least want it. In heavy soil, that one piece of housekeeping is the difference between a clump that reappears in spring and one that does not.
The plant is fully hardy and needs no protection in all but the coldest gardens. A pot is the exception: the roots are far more exposed in a container, so move it against a wall or sink the pot into the ground for the winter.
Keep a short note each year of the date the buds first appeared and the dates of your two cuts. Within two seasons you will know your own garden's timing well enough to plan the harvest a month ahead, which is the single most useful thing you can know about this plant.