Citrus Tree Care: Tips for Thriving Trees and Bountiful Harvests

Citrus tree care

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Citrus trees are an ideal fruit tree for our hot and humid climate and can be grown either in the ground or in a large pot. Pot-grown citrus make a decorative addition to balconies or courtyards but will not produce as many fruit compared to citrus grown in the ground.

In-ground planting allows citrus trees to establish deep root systems, enabling them to access a wider range of nutrients and moisture, which is particularly beneficial in hot environments. This method is suitable for gardeners who have ample outdoor space and desire a more permanent, landscape-integrated option.

Citrus trees in grown in large pots are great for those with limited space, such as in urban settings or on patios and balconies. Container growing provides the advantage of mobility; the trees can be moved to optimise sunlight exposure or to protect them from extreme weather conditions. Additionally, pot cultivation allows for better control over the soil quality and drainage, which is crucial for healthy citrus growth.

Soil preparation

Citrus trees thrive in well-draining soil with a pH range of 6.0-7.5. Most garden centres sell pH testing kits for home use to ensure you have the correct pH for your citrus tree. Incorporate well-rotted compost, and aged manure into the soil to improve soil structure, provide nutrients, and aid water retention.

If growing your citrus in a pot, select a premium potting mix.

Fertilising your citrus tree

Feed your citrus at the beginning of each season to encourage growth and increase fruit production. Apply around the drip line (the outermost edge of the tree canopy), to target the feeder roots which are found in the top 30-45 of soil. Feeder roots contain the most active root hairs and are responsible for absorbing nutrients and water.

Pesticides and pest management

Citrus bug

Australia is home to several common citrus pests that can affect the health and productivity of citrus trees.

  • Citrus gall wasp (Bruchophagus fellis): This pest lays eggs in young citrus stems, forming galls that can weaken the branches and affect fruit production. Prune and destroy affected branches.
  • Bronze orange bug/stink bug (Musgraveia sulciventris): These bugs feed on citrus sap, causing leaves to turn yellow and drop prematurely. They also emit a foul odour when disturbed. Regular inspection and manual removal can help control their population.
  • Citrus leafminer (Phyllocnistis citrella): The larvae of this pest tunnel through citrus leaves, creating silvery trails. While it doesn’t usually cause severe damage, it can affect the aesthetics of the tree.
  • Aphids: Various species of aphids can infest citrus trees, causing distortion of new growth, yellowing leaves, and the production of sticky honeydew that attracts sooty mould. Natural predators like ladybugs can help keep aphid populations in check.
  • Scale insects: Soft and armoured scale insects can be a problem for citrus trees. They feed on sap and can weaken the plant, causing leaves to yellow and drop.
  • Whiteflies: These small insects suck sap from citrus leaves, causing yellowing, wilting, and stunted growth. They also produce honeydew, leading to sooty mould growth.
  • Mealybugs: Mealybugs feed on citrus sap, secreting honeydew and attracting ants. They can also transmit plant diseases.
  • Thrips: Thrips can damage citrus flowers and young fruit, causing scars and deformities.

Regular monitoring allows you to swiftly detect any signs of unwelcome visitors. If you happen to spot any pests, use an organic pesticide tailored to citrus pests.

Mulching

Cypress mulch

Mulching helps with moisture retention, keeps the roots cooler in summer and suppresses weeds. Add a 5 cm layer of organic mulch and spread it around the base of a citrus tree.  As the mulch decomposes, it enriches the soil with organic matter, provides an environment for beneficial microbes and improves soil structure.

Do not allow mulch to come into direct contact with the tree trunk, which can lead to collar rot.

Watering

Established vs. Newly Planted Trees:

  • Newly planted: Water immediately after planting. For the first week, water every other day, then 1-2 times a week for a couple of months.
  • Established trees: These typically need to be watered every 1-3 weeks, but this can vary depending on soil and weather conditions.

It’s better to water deeply and less frequently than to give shallow, frequent watering. Deep watering encourages roots to grow deeper, making the tree more drought-tolerant.

When watering, make sure that the water penetrates well into the soil and not just the top few cm. Use a soaker hose or drip irrigation system to deliver water directly to the base and root zone, ensuring deep penetration and less water loss due to evaporation.

Container-grown citrus will require more frequent watering than citrus in the ground. However, ensure pots have proper drainage holes to prevent them from becoming waterlogged.

Staking

Staking your citrus

Stake young citrus trees to ensure they grow straight and are protected during windy conditions. Use wooden stakes that are as tall as the tree. Young citrus trees will need to be staked to ensure they grow straight, especially when they are young or newly planted, which can help them grow straight and provide additional support in windy conditions. Opt for wooden stakes around 150 cm long. For larger trees, two or three stakes may be necessary.

Position the stake 15 cm from the trunk, and push it into the ground at least 30 cm to ensure it is stable. Place multiple stakes evenly around the tree, spacing them apart in a triangular configuration. Use a stretchy garden tie to tie the tree to the stake. Avoid wire or thin string as it can cut into the tree bark. Make sure the tie is snug, but not too tight, the tree should still be able to move slightly.

Varieties to grow

Buddha's hand citrus
Buddha’s hand citrus (Citrus medica var. sarcodacylis)

Most varieties of citrus grow well in the Illawarra and Sutherland Shire. Choose fruits your family enjoy eating, or consider growing varieties not readily available in supermarkets. The Australian finger lime (Citrus australasica) is a native species of citrus with finger-shaped fruits that contain juice-filled vesicles. The taste is similar to that of a lime. This tree grows well in the region but can be a little more fussy than other citrus species. Kumquats (Citrus japonica) and calamondins (Citrus × microcarpa) are grown for their small and tart fruits that make great jams or candied. Buddha’s hand (Citrus medica var. sarcodacylis) is an unusual species of citrus with yellow, hand-shaped fruits. The fruit contains almost no flesh, however, the peel is highly fragrant and is used as a replacement to lemon or lime zest, or candied.

If you have any citrus-related questions, feel free to visit us in store for expert advice.

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