The fruits of the lemon tree are one of the most ubiquitous of all citrus fruits because of their various culinary and therapeutic uses, among many other benefits.
Having your own lemon tree will give you a free source of this fragrant and nutritious fruit. Not only that, this small tree gives a burst of bright and cheerful colour as it flowers and its fruits ripen.
The Basics of the Lemon Tree
Lemon, or Citrus limon, is a species in the flowering plant family Rutaceae. It is a small evergreen native to South Asia, particularly north-eastern India.
Lemon trees are cultivated primarily for their fruit. They are famous for their yellow, ellipsoidal fruit with a distinct flavour and aroma, and are a good source of vitamins and minerals.
There are several varieties of lemon tree, each distinguished by the characteristics of its fruit.
Domestic lemon trees grow on average around 3 to 6 metres tall and 4.5 to 6 metres wide.
Bonnie Brae
This lemon tree has oblong fruits with smooth, thin skin. They are seedless and are grown primarily in the United States.
Eureka
Also known as Four Seasons, the Eureka lemon is one of the most common supermarket lemons. Young Eureka lemon trees are also available to home gardeners. It can produce flowers and fruits together all year round.
Eureka lemon trees can grow up to 6 metres tall.
Lisbon Lemon
The fruit of the Lisbon lemon tree, like the Eureka, is also one of the common supermarket lemons. Its fruit has thinner and smoother skin compared with the Eureka. The Lisbon lemon is either seedless or has very few seeds.
Lisbon lemon trees can grow around 6 to 9 metres.
Femminello St. Teresa (Sorrento)
This lemon tree is native to Italy. Its fruit, which is high in lemon oils, is traditionally used for making limoncello.
Meyer Lemon
Although technically not a true lemon, the Meyer lemon sits under the same genus, Citrus, and is included here because it is popular as a home and supermarket lemon.
The Meyer lemon is a hybrid native to China, a cross between mandarin/pomelo and citron. It was widely grown commercially but the original trees were infected with a virus and had to be destroyed. An "Improved Meyer Lemon" free of the virus was released in the mid-1970s.
This lemon tree grows to around 2 to 3 metres tall. It has dark shiny leaves and white flowers with a purple base. The Meyer lemon fruit is rounder and less acidic than the fruit of the true lemon tree.
Planting Your Lemon Tree
Lemon trees are sensitive to cold, even more so than most citrus trees.
In Australia, choose a position on the north side of the garden to maximise sun exposure. These trees grow best at around 26 to 28 degrees Celsius.
Most lemon trees need to stay above 13 degrees Celsius, or they will go dormant. You can also choose to plant your lemon trees indoors or in a greenhouse to keep them away from cold wind and protect them from temperature drops.
Plant your lemon tree in full sun, as they need plenty of light.
Lemon trees prefer slightly acidic soil of around pH 5.5 to 6.5 but can tolerate a wide range of soils. The most important requirement is good drainage, as lemon trees do not like soggy soil. Working a quality soil amendment through your planting area before you dig improves drainage and gives young roots the best possible start.
If planting from a sapling, do not bury all of its roots. Dig a hole shallower than the root ball, place your lemon tree in the hole, and backfill. Water deeply after planting and mulch to retain moisture. Water newly planted lemon trees every other day, especially in warm climates, until they are established. Keep the soil moist but make sure it does not become soggy.
If planting from seeds, wait until your seedlings are about 15 to 30 centimetres tall before transplanting them outdoors or into another container. Lemon trees also grow well in large pots; a good-quality plastic pot with adequate drainage holes gives you the flexibility to move the tree to a sheltered spot during cold snaps.
Caring for Your Lemon Tree
Once your lemon trees are established, approximately a month after transplant, water once a week.
Feed your lemon tree using a mild fertiliser every six months. Make sure to fertilise only from the base of the tree, as you do not want to burn the leaves with fertiliser.
To keep pests off your lemon tree, spray its leaves regularly to remove dust and pests.
Lemon trees do not usually need to be pruned formally. However, you can still prune them to size according to your preference, especially for indoor trees.
Prune dead leaves, stems, flowers, or fruits from your lemon tree. Snip away all diseased parts to avoid the spread to other parts of the tree and to other plants.
Protect young trees from frost by covering them with a tarp or blanket. A tree guard placed around the trunk also shields the bark from wind, wildlife, and accidental damage while the tree establishes. If you need to stake a young tree for support, use a soft plant or tree tie to secure it without cutting into the bark.
Common Problems with Lemon Trees
Overwatering can cause stress on your lemon tree. Shallow watering can also pose problems, so avoid placing your lemon trees on lawns with sprinklers to prevent root rot.
Lemon trees bring a lot of benefits through their fruits and even their leaves, but these citrus plants are not free from pests and diseases.
Citrus Canker
Lemon trees can get citrus canker, which is a highly contagious infection. It results in leaf loss, fruit drop, and dieback.
A copper fungicide can be used as a preventive measure. A lemon tree infected by citrus canker will need to be destroyed.
Sooty Mould Fungus
This fungal infection can cause black leaves. Aphids, mealybugs, and whiteflies can bring this infection to your tree through their excretions.
To prevent or control sooty mould, address the pest issues first by spraying your lemon tree with neem oil. Spray on top and underneath the foliage to reach pests hiding in those spots. Repeat insecticide application in about two weeks.
After controlling the pests, apply a liquid copper fungicide to contain the mould growth.
Greasy Spot Fungus
When your lemon tree has the greasy spot fungus, the underside of its leaves will have yellow-brown blisters. These blisters will eventually look oily as the disease progresses.
Like the previous diseases, a copper fungicide will address greasy spot fungal issues on your lemon tree.
Brown Rot or Collar Rot
The phytophthora fungus causes brown rot or collar rot on your lemon tree. When your tree is infected, hard dark brown patches will appear on the trunk. There may be some excretion of liquid oozing out of the affected area.
The brown patches will eventually dry and crack, leaving sunken marks along the trunk.
This fungus can come from moist soil. Remove infected branches by pruning and treat with the appropriate fungicide.
Anthracnose
Like brown rot, anthracnose is caused by a fungus from wet soil, usually after prolonged rain. This fungus will cause twig dieback, stained fruits, and leaf drop.
The botrytis fungus, also known as grey mould, is another disease that can affect lemon trees after prolonged periods of rain.
Ready to set your lemon tree up for success? Browse our soil amendments and tree guards to give it the best possible start.
