Gadenin日本語Get the appWhen the scent is strongest
Two things decide how much lemon there is in the leaf: the time of day and the point in the season. Pick in the morning once the dew has gone but before the sun has been on the plant for long, and pick in the stretch just before the flower buds open. Those leaves are noticeably more fragrant than the same plant a fortnight later.
After that the plant coarsens fast. Once flowering is underway the leaves get tougher, the lemon note thins and a slightly musty background comes forward. This is the main reason to cut a clump back before it flowers, and why a hard midsummer cut is worth making: the fresh flush that follows is as good as the spring growth.
Leaves picked in rain or straight after watering are full of water and taste weak. If you are picking a quantity to preserve, wait for a morning after a couple of dry days.
How to cut, and what it does to the plant
Cut whole stems just above a pair of leaves rather than stripping individual leaves off. Two shoots break from that joint, so every harvest makes the clump bushier and picking doubles as pruning. Stripping leaves leaves you with bare stems that do nothing.
You can take up to half of a healthy established clump at one go without checking it. In the first season after planting, take a third at most and let the plant build a root system; from the second year on it will out-grow anything you can reasonably pick.
Why drying disappoints, and what to do instead
Lemon balm loses more of its aroma in drying than almost any other common herb. The compounds that make the lemon smell are volatile and they go off with the moisture, so a jar of home-dried leaves that smelled wonderful when it went in often smells of hay by midwinter.
Freezing keeps far more. So does putting the fresh leaf straight into something else, whether that is a syrup, a vinegar or an oil. Treat lemon balm as a fresh and frozen herb, and dry it only when you specifically want bulk for tea and accept that it will be a shadow of the fresh leaf.
Ways to keep it, and what each is good for
Choose the method from the use rather than the other way round. Most disappointment with stored lemon balm comes from drying a large harvest that was really destined for cold drinks.
| Method | How long it keeps | Best for |
|---|---|---|
| Stems standing in water on the counter | Two to three days | Whatever you are going to use today |
| Wrapped in damp paper in the fridge | About five days | Small amounts for cooking and drinks |
| Whole leaves frozen flat in a bag | Six months | Tea and infusions; the leaf collapses on thawing |
| Chopped and frozen in ice cubes | Six months | Dropping straight into a cold drink |
| Steeped into a sugar syrup, refrigerated | A month | Drinks and desserts; keeps the scent best of all |
| Air dried in the shade, sealed in a jar | Three to four months of useful scent | Bulk tea, when you accept a weaker result |
Do not wash leaves you intend to freeze or dry unless they are actually dirty. Water on the leaf slows drying, encourages browning and dilutes what you are trying to keep.
If you do dry it, dry it fast and dark
Speed and darkness are what preserve the scent. Strip the leaves from the stems, spread them in a single layer on a rack somewhere warm, shaded and with air moving, and get them crisp in two or three days rather than the week a hanging bunch takes. Leaves that go leathery and brown over a fortnight in a humid room have lost the lot.
Store them whole in a sealed jar in the dark and crush them only as you use them. A jar left on a sunny windowsill will be worthless in a month, however well it was dried.
When a clump stops giving you anything worth picking
A plant that has flowered, or one whose center has gone woody and bare, will not produce good leaf again on its own. Cut it hard to about four inches (10 cm), water it, and it will give you a clean flush in two to three weeks provided there are still six or more weeks of growing weather left.
It is worth noting each year when you made each cut and how long the regrowth took, alongside the date the first buds showed. Lemon balm runs to flower at much the same point each season in a given garden, and after two years of notes you will know the week to pick heavily and the week to cut, without having to watch the plant daily.