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The Good Old Lemon Tree

© John Bottomley

Citrus trees are grown widely in this Mediterranean climate and are for the most part very decorative trees. In Asian countries they are sometimes shaped and pruned for ornamental purposes, and are grown in the ground or in containers.

Citrus trees came to Australia first in 1788, when Captain Arthur Phillip sailed here with orders to introduce plants and seeds. The Lemon Tree is very popular and very prolific bearer of fruit in this part of the world. We have a couple of these and it seems we get good lemons for most of the year; we must be doing something right.

The better of the two trees we have is planted in an open and sunny position, just outside the back door, and gets plenty of good rotted compost and animal manure. The other one does not give as much fruit, but I suspect it is because the position we chose is not sunny enough, and there are too many other large trees around which take a lot of the goodness out of the soil. This winter I am going to transplant it in a more sunny position.

It is my understanding that running a shallow ditch around the tree may be the best way to water young lemon trees, the ditch should not be too close to the trunk. The ditch will serve as a reservoir and during dry periods should be filled two or three times a week. Regular watering in the summer is absolutely essential even when the trees are mature; those deprived of water will not grow healthy crops.

I usually apply a citrus fertiliser during the months of August, November and April. A balanced fertiliser is best and the manure should be spread evenly throughout the root zone about 1 metre (3.3 feet) from the trunk.

Some of the pests associated with lemon trees are red scale, brown scale, and citrus aphids. It is best to apply white oil to the scale insects in January, February and March. Three applications will be required if the infestation is very severe. It is recommended that non-toxic sprays are very useful and can be used against a variety of pests without a residual build up.

Some fungal problems can occur with lemon trees such as a soil fungus called 'collar rot', and another type of fungus called 'sooty mould'. Planting too deeply can cause 'collar rot', so can heaping soil, compost, or animal manure around the bud. The first signs of this disease are gum beads around the affected area. After some time the bark rots and peels off. If the tree starts to decline, the tree is usually too far-gone to revive. It is possible, if the disease is caught in the early stages, to cut off the affected bark and paint the wound over with Bordeaux paste.