How To Grow Curry Leaf Tree In UK And How to Store Its Leaves?
Curry leaf tree, botanical name is Murraya koenigii, has extremely aromatic leaves, which are used in making various curries all over India, especially in southern India and Sri-Lanka. The leaf pattern is bi-pinnate. It's flowers and fruits are somewhat similar in looks to the famous, medicinal Neem Trees of India, Azadirachta indica. Because both the tree leaves look similar, but this is not bitter, it is sometimes called Meetha Neem (sweet Neem). In India, they grow in most types of soil and can grow up to 2-2 1/2 meters. Leaves are most flavoursome when used fresh, straight off the tree. If you can find them only rarely, you can freeze them, but do not wash before freezing. Any water on the leaves will 'burn' them. Leaves can be bought from many Indian grocers in UK. They are sold either fresh or dry in packets. Fresh have better flavour. Dry leaves have hardly any flavour, but better than none.
In cold countries, the 'tree' has to be kept indoors, except in summer months. It is not frost hardy. You can buy small trees from some nurseries in UK, but make sure that you do not confuse it with the so called 'Curry plant' Heichrysum italicum. Curry leaf trees have small, berry like fruits with a single stone. They become dark purple in colour and taste sweet when ripe, but not really nice enough to be eaten as a fruit. These trees are difficult to grow from seeds, which remain viable only for a short period after falling off the tree. In India, people often harvest new plants from under the existing tree. I remember my father potting lots of little ones and passing them on to friends and family. It is perhaps easier to grow from a cutting. I have tried it; I got one plant survive from 3 cuttings that I started with, not bad!
Remember that the tree often loses all its leaves during winter. Do not worry, it is not dead, just resting. Don't throw it out!
Edited April 2021
Curry leaves give a very distinctive aroma to a dish, not replicated by any other herb even remotely. Apart from cooking they are also used in several natural remedies including for digestive system ailments, skin conditions and diabetes.
Harvesting seedlings: Curry leaf trees produces white flowers in summer, which then produce small, berry like fruit. The berries mature into purple fruits, which then fall to the ground. They have a hard stone in the centre, the seed. As monsoon usually follows the fruit fall, you often see many seedlings appearing under the parent tree. It is best to harvest these seedlings and pot them immediately after digging them out.
Sowing: You may get lucky if you can find and sow seeds immediately after they fall, not yet dry. If they dry out, they will not germinate. Sow in soil that is well draining, perhaps with a little grit added.
Cutting: Select a semi hardwood branch, with a couple of bi-pinnate leaves attached to it. Cut the branch at the base with a sharp knife, cleanly. Remove lower leaves, if there are more than 2-3. Dip it in rooting powder, if you have any. Pot it in a mix of 50 percent potting compost and 50 percent aquarium gravel or a mixture of 50 percent vermiculite and 50 percent perlite. This will prevent water clogging at roots. Make a hole in the compost using the back of a pencil or similar. Place the cutting inside, gently firming the soil around it. Water it a little. Enclose the pot in a plastic bag, transparent one so you can keep an eye on it. Keep it in a warm, but not sunny place. If you are lucky, it will begin to make roots in 3-5 weeks.
Caring for the plant: Here in south England, I keep mine in the kitchen the whole year round, taking it out only in very hot weather. It must be brought indoors during cold weather. When placing it outdoors during summer, find a sunny position, not too windy. Water it in summer regularly, less often in winter, after checking the soil for moisture. Do not let it stand in water.
Storing fresh leaves: Either leave them on their stalks or strip them off the stalks. Wash well and spread out on a towel for 12 hours, until all water has dried off. 1) Place in a plastic bag, press to remove as much air as you can and seal. Keep them in fridge. 2) Wrap them in a paper towel, then keep in a plastic bag in the vegetable drawer of the fridge. 3) They can be frozen like this, if you can buy them only occasionally. You can take out as many as you want and use them directly from the freezer, without defrosting. 4) You can dry washed leaves. Spread out on a towel/newspaper, in shade or in a warm room or a conservatory. Then store them in airtight jars.