Harvesting and Drying Lemon Verbena for the Strongest Scent

Cut in the morning, in dry weather

The lemon scent lives in oil glands on the leaf surface, and the amount of oil in a leaf swings a long way with the weather and the hour. Oil content peaks in the early morning after the dew has lifted but before the sun has been on the plant for long, because heat volatilises the oils away through the day. Cut at midday in a heatwave and you can lose a noticeable amount of the fragrance you were harvesting for.

Weather matters as much as time of day. Leaves cut after a run of warm, dry, sunny days are markedly stronger than leaves cut in a wet week, and they also carry far less water into the drying rack, which means they dry faster and are less likely to go moldy or brown. If you have a choice, wait for the dry spell.

The single biggest harvest of the year is the one you take just before the plant starts to shut down for the cold season. Growth has stopped adding new leaves, everything on the plant is mature, and it is all going to fall off anyway. Strip that plant properly rather than losing a full season of leaves to the ground.

Cut whole stems, and cut to a leaf pair

Do not pick lemon verbena leaf by leaf. It is a shrub and it responds to being cut, so harvesting is also pruning, and if you take single leaves you get all of the loss and none of the benefit. Take whole stem tips instead and strip the leaves off indoors.

Cut just above a pair of leaves, a quarter inch (5 mm) above the joint. Two new shoots normally break from that pair within a fortnight in warm weather, so every cut you make in the first half of the growing season increases the amount you can pick later. This is why a plant that is harvested regularly ends up bushier and more productive than one that is picked at sparingly.

Through the growing season you can take up to a third of the plant at a cut and expect it back within a month. Repeat cuts of that size two or three times over a season are entirely normal for a well-fed, well-watered plant in a decent pot. Stop cutting as the season cools, so the last flush of growth has time to firm up before the cold, and then take the whole crop at once at the end.

1. Take stem tips, not individual leaves Snip six to eight inches (15 to 20 cm) of shoot with clean pruners or scissors. Strip the leaves indoors on a tray where you are not fighting the plant.
2. Cut a quarter inch above a leaf pair Cutting into the bare stem between pairs leaves a stub that dies back and can rot. Cutting just above the pair gives you two new shoots from that point.
3. Take a third at a time in full growth A healthy plant regrows that in three to four weeks in warm weather. Taking half at once slows it down for the rest of the season.
4. Strip the whole plant before the cold Once nights are cooling the leaves will fall regardless. Cut the lot, dry it, and let the plant go into its bare dormant state with nothing wasted.

Drying: cool, dark, and moving air

Lemon verbena dries better than nearly any other culinary herb. Where mint and basil fade to hay, verbena holds its lemon character for a year or more if you dry it right, and the whole point of growing a large plant is to have a jar of it through the cold months.

The three things that spoil dried verbena are heat, light and still humid air. Heat drives off the oils you are trying to keep, light bleaches the leaves from green to a dull khaki and takes the aroma with it, and still damp air lets the leaves brown or mold before they are dry. An airy, shaded room, a spare cupboard with the door propped open or a dry shed all work. Direct sun on a windowsill does not.

Bundle the stems loosely, no thicker than you can circle with a finger and thumb, and hang them upside down. Loose bundles matter more than most people expect; a tight fat bunch stays damp in the middle and browns there. Depending on humidity the leaves are ready in one to two weeks, when they are brittle enough to crumble at a touch but still green rather than brown.

Strip the dry leaves from the stems and store them whole, not crushed. Every broken edge is a place for the oils to escape from, so a jar of whole leaves is still fragrant long after a jar of crumbled ones has gone flat. Crush them between your fingers as you use them.

Store dried leaves whole in an airtight jar in a dark cupboard, not in a clear jar on an open shelf. Light is what turns a bright green jar of verbena into a brown one with no smell, and it does it within a couple of months.

Using and keeping the crop

Dried lemon verbena is at its best steeped rather than cooked. Pour water just off the boil over a few leaves and leave them four or five minutes; boiling them hard drives the aroma into the air instead of the cup. The same steeping approach works for infusing cream, syrup, custard or a jar of sugar, where a handful of dried leaves left in for a fortnight will scent the whole jar.

Fresh leaves are more strongly lemon-scented than dried ones but rather tougher in texture, so they are better infused and removed than chopped in and eaten. If you want them in a dish, shred them very finely and use half what you would use of a soft herb.

A properly dried, whole-leaf jar kept dark stays good for a year, which conveniently carries you from one big pre-cold harvest to the next. Test it by rubbing a leaf between your fingers before you use it; if the smell is faint, no amount of steeping will bring it back and it is time to start the new jar.

Notes worth keeping about the harvest

The harvest is where record-keeping pays back fastest, because you can compare one batch with another and actually taste the difference.

Note the date of each cut and roughly how much you took, so you can see how many weeks the plant needed to regrow and plan the next cut instead of guessing. Note the weather in the days before a cut, and whether that batch smelled stronger or weaker than the last, since after two seasons a clear pattern emerges about dry spells. Note the date of the final pre-cold harvest and the total dry weight you got from the plant; that number tells you honestly whether last spring's cutback and this summer's feeding worked. Note where and how each batch was dried and how long it took, and note the date each jar was filled so you can tell at a glance whether the jar at the back of the cupboard is this year's or last.