Citrus trees both lemon and orange make interesting and attractive indoor plants.
They provide year round interest, with fragrant white flowers, followed by small fruits which take 4-6 months to reach full size. The fruits can be picked at any time after ripening, and will retain their flavour on the tree for several months.
All citrus plants enjoy high light levels, so smaller plants will do well on a windowsill in the house. Larger plants need a conservatory, greenhouse or sheltered summer garden, but should be given supplementary light if they are to be kept away from windows indoors. Be careful not to allow leaf scorch in direct summer sun through glass.
Flowers and Fruit - Generally flowering takes place in May, but can occur several times in the year with fruit setting each time. An enormous number of fragrant flowers appears, but only about 1% will set on the large trees (more than this would overload the branches when the fruit reaches full size). Calamondins, kumquats and some lemons set a higher percentage of fruit and may even have to be thinned to avoid weighing the branches down too much.
Dry, hot conditions will not favour fruit set, which can be improved by misting the flowers. Regular pinching out of branches will encourage bushy growth nearer the middle of the tree, and this can be carried out at any time of year.
Pruning of large branches is best done in February, just before growth starts speeding up, bearing in mind that Citrus trees store excess food in their leaves, so removing too much leaf may result in a poor fruit crop.
With the right care indoor citrus trees are not only an attractive addition to your home, but can yield a good supply of your own citrus fruits.