Simple guide to Citrus
Citrus are shallow rooted trees which like good drainage and plenty of sun. They will grow in most soils except poorly drained, wet ones.
Lemons
Lisbon: Thick skinned, long bearing variety, usually thorny, medium height, strong flavour, and good for Melbourne climate. Vigorous growth. Good in clay soils.
Eureka: Tend to be thornless, good in cooler climates, more Summer bearing than other varieties, needs well drained soil, does not grow well in clay.
Meyer: Thin skinned variety, almost cross between an orange and lemon with a sweeter, less acidic taste. Cold tolerant, smaller growing and not very thorny. Vigorous growth. Better for pots.
Limes
Limes can be sensitive to frost, so in Melbourne they will need some protection, either up against a brick wall or close to a house in a sunny position.
Tahitian: This variety is the best for Melbourne’s climate and bears fruit from Autumn to Spring that can be used in drinks and cooking.
Kaffir/Makrut: The aromatic leaves can be used in Thai cooking.
Oranges
Navel: Thin skinned and seedless fruit, borne in Winter and early Spring.
Valencia: Late Spring – early summer fruit bearing. Will fruit in cooler climates.
Mandarins
Full sun position. Fruit sets in late Autumn to Winter. Imperial variety has few seeds. Prone to alternate fruit bearing, this may be reduced by thinning heavy crops.
Grapefruit
Warm sheltered position required in Melbourne. Varieties include March Seedless and Wheeny (cooler climates).
Cumquats & Calamondin
Highly ornamental small tree which is more cold resistant than other citrus. Fragrant flowers and attractive small bitter orange fruits are suitable for marmalade. Excellent in tubs.
Keeping a citrus tree healthy
Citrus are hungry plants that need to be well fed in order to produce a beautiful crop of fruit. Adding an aged manure and some compost will help keep your citrus at its best.
When watering, water out to the edge of the tree canopy, to ensure the shallow roots spreading across the top of the soil have access to water.
If the young tree has a lot of flower buds and/or fruit, you should consider removing some. This will mean the tree will expend less energy in fruit production and reduces risk of nutritional deficiencies.
If you notice ants climbing around in the tree, you probably have scale. Treat the scale with horticultural oil, which is non-toxic. You may need to reapply a few times to completely remove the problem.
Yellow leaves usually indicates a lack of nutrients. Try feeding with a liquid fertiliser as well as with blood and bone, cow or poultry manure in Spring.
Straggly trees can be thickened up with a good prune. In Spring/Summer, cutting back the tree will cause a flush of new growth and you will end up with a bushier shaped tree.
Swellings on the branches mean that your tree is playing host to citrus gall wasp. Winter is a good time to control the wasp, because it is dormant. Cut off the affected branches and through them in the bin.
If your tree has dropped a lot of leaves, it may be suffering from collar rot. Check the bark around the trunk to see if there is rotting or other damage. Clear mulch away from the base, and treat with a copper fungicide such as Bordeaux Paste.
