Winter Citrus Care

Unlike many other fruits, citrus fruit will not ripen or become sweeter after picking. So, it’s important to harvest fruit only once they’re ready. Commercial citrus orchards often use special tools to measure the ripeness of citrus fruit. The best way for home gardeners to test ripeness is to try one! Once the fruit is the correct colour (e.g., oranges and mandarins have bright orange skin), pick one fruit and see whether it’s as juicy and sweet as you’d expect. If it’s not, wait another week and try again. Sweetness and juiciness increase over time. However over-ripe fruit can start to become less juicy.

Don’t be concerned if your once-orange Valencia Oranges start to turn a bit green. The longer the fruit is left on the tree during warm weather, the chlorophyll (green pigment in plants) starts to accumulate in the skin. It doesn’t adversely affect the sweetness or the taste of the orange. In fact, many people think that these re-greened oranges taste better! Valencia Oranges can be left on the tree for several months.

Fruit Fly is a serious citrus pest. Adult Fruit Fly lay eggs into the skin of developing fruit, the eggs hatch and larvae burrow into the fruit. As citrus fruit continues to mature during winter, it’s important to maintain Fruit Fly prevention measures.

Spray Yates Nature's Way Fruit Fly Control over the lower foliage, or a band around the trunk, each week, until all fruit is harvested. It attracts and kills both Queensland and Mediterranean Fruit Fly using a combination of a protein and sugar-based bait and an insecticide derived from a naturally occurring soil bacteria.

Also, pick up any fallen and infested fruit and dispose of it in a plastic bag. This helps to stop the Fruit Fly life cycle.

Lumpy swellings along the stems of citrus trees are an indication of Citrus Gall Wasp. Citrus Gall Wasp (Bruchophagus fellis) is native to warm coastal areas in New South Wales and Queensland but has also become an increasing problem in Victoria and Western Australia. Its original host was the native Australian Finger Lime but can also seriously affect other citrus including Lemons, Grapefruit and Oranges.

There are 3 main stages in the Citrus Gall Wasp life cycle: 1. The small black adult wasp lays eggs underneath the bark on soft new spring growth. 2. Larvae hatch from the eggs, eat the stem tissue and the lumpy galls form around the developing larvae. 3. The larvae mature into the adult wasp which emerges from the gall the following spring, leaving small pin-prick holes.

The galls not only look unattractive, but they can also lead to poor plant health and a reduced harvest. It’s important to be vigilant and look out for these galls and winter is an ideal time to act to reduce this nasty pest, before the adult wasps emerge in spring.

There are no sprays registered for controlling Citrus Gall Wasp in home gardens, and once galls are formed the damage is permanent.

Prune off affected stems and place these sections in a sealed plastic bag and put them in the garbage (don’t put gall-infested stems in the compost bin). Disposing of affected stems in winter before the adult wasps have emerged stops the life cycle and helps to reduce new infestations in spring.

Some citrus trees are less cold-tolerant than others and can suddenly go yellow with the onset of cold weather. There is no need for concern, the plant is simply struggling to take up nutrients.

Avoid feeding, move potted plants to a warmer position, and wait for warmer weather to return.

Keep the soil or potting mix consistently moist. Too much moisture can lead to Citrus fruit splitting. Insufficient moisture can adversely affect fruit quality.

At the end of winter, it’s time to start feeding Citrus trees, to prepare them for the busy spring season. Apply Yates Thrive Natural Citrus & Fruit Organic Based Pelletised Plant Food around the root zone of in-ground and potted Citrus trees and water in well.

Refresh the mulch around the root zone of citrus trees, however, keep it from contacting the trunk, as this can promote diseases such as Collar Rot.

If there are shoots growing from beneath the graft, trim these back flush with the trunk. These shoots are from the tree's hardy rootstock, but will not develop the fruit you're after. They can be viciously thorny and also eventually take over the tree if not removed.

For old citrus trees that won’t bounce back, sometimes you can hard prune or ‘skeletonise’ to rejuvenate them. This is best done in late winter after fruiting and before new leaf and stem buds form.

Using a bush saw, bow saw, or chainsaw prune the tree back to the trunk and major branches.

Avoid making horizontal cuts as these will pool with water and be a site for infection. Prune on an angle so the water drops off.

Feed soon after pruning with Yates Dynamic Lifter Soil Improver & Plant Fertiliser.