Citron (Citrus medica) is an evergreen, irregular, open-headed, slow-growing shrub or small tree, reaching a height of about 2.5-4.5 m, with large, light green leaves, lemon scented with slightly serrate edges and long spines at the leaf axils. The flowers are generally unisexual providing self-pollination, painted purple on the outside and are followed by large, ovate or oblong, narrowing up till the stylar end, fragrant fruits that contain a large number of seeds. The rind is leathery, furrowed, and adherent. The inner portion is thick, white and fleshy and the outer portion is uniformly thin, and very fragrant. The pulp is usually acidic, but also sweet and even pulpless varieties are found. The pulp is small and greenish and the juice is scarce and very acid in most types.
Citron is very tender and extremely sensitive, maybe the least resistant to winter temperatures of all the Citrus fruits because of its continuous growth tendency, with almost no dormancy, blooming several times a year. The color varies from green, when unripe, to a yellow-orange when overripe. The citron would never fall off the tree and could reach 4-5 kg if not picked off timely or even early. However, they should be picked off before the winter as the branches might break, or bend to the ground.
Grow Citron in a bright place, with direct sunlight. As they can't stand temperatures below zero they should be grown in cold green houses or at least in a sheltered place. When all risks of late freezing have gone by, place them outside or remove the protections. Mulch the soil around the young plants, using straw or dry leaves. Young plants usually are provided with stakes, so that they can develop erect.
Citron need a soft and light soil, with good aeration and very well drained. Towards the end of the winter, or the beginning of the spring, add some mature manure or earthworm humus to the soil near the trunk. Water rarely, about once every 4-5 weeks with 1-2 buckets of water, keeping the soil dry for a few days before watering again.
Citron trees are propagated from cuttings taken from branches of 2-4 years old and quickly buried deeply in soil without defoliation. For quicker growth, the Citron may be budded onto rough lemon, grapefruit, sour orange or sweet orange but the fruits do not attain the size of those produced from cuttings, and the citron tends to overgrow the rootstock.
