During the winter months, it is important to provide proper care for Citrus plants to help them produce a bountiful and heavy crop. In this article, we will discuss the key aspects of winter citrus care, including when to harvest, maintenance tasks, pruning techniques, and common pests to watch out for, like Fruit Fly and Citrus Gall Wasp. Here's how to care for your Citrus plants this winter.
Winter is peak harvest time for many Citrus. It's so wonderful to be able to step out into your backyard or courtyard and pick your very own fresh and delicious Mandarins, Oranges, Lemons and Tahitian Limes. But how do you know when the best time is to pick Citrus?
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 a 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.
Signs of pest attack include small puncture marks. Fruit Flies lay their eggs by piercing the skin of the fruit, leaving behind tiny holes or puncture marks. These marks may not always be visible to the naked eye but can be felt when running your fingers over the surface.
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 (Bruchophagus fellis). Citrus Gall Wasp 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 three 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 to control 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, so their leaves can suddenly yellow with the onset of cold weather. There is no need for concern, the plant is simply struggling to take up nutrients.
This isn't due to a lack of fertiliser, so avoid feeding. Simply move potted plants to a warmer position, and wait for warmer weather to return.
Citrus plants are heavy feeders, so like to be fed well and often. At the end of winter, it's time to start feeding Citrus trees to prepare them for the busy spring season. Apply a specialised citrus food, such as Yates Dynamic Lifter Fruit & Citrus Plant Food Pellets or 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.
Apply a fresh layer of mulch, such as Yates Dynamic Lifter 4 in 1 Mulch, around the root zone of Citrus trees. Mulch helps retain moisture in the soil, regulates soil temperature, suppresses weeds, and provides a nutrient-rich environment for beneficial microorganisms. Additionally, mulch can help protect the roots of citrus trees from temperature fluctuations and extreme weather conditions during the winter months. However, keep it from contacting the trunk, as this can promote diseases such as Collar Rot.
Keep the soil or potting mix adequately watered to maintain consistent moisture. Excess water or too much moisture can lead to Citrus fruit splitting. Insufficient moisture can adversely affect fruit quality.
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.
As Citrus trees age, it is not uncommon for them to become less productive. However, with proper care and maintenance, you can help rejuvenate your older citrus trees and encourage them to produce more fruit during the winter months.
Hard pruning involves cutting back a significant portion of the tree's branches, typically removing up to one-third of its growth. You can use a bush saw, bow saw or chainsaw. While this may seem drastic, it can actually help rejuvenate the tree by promoting new growth and improving air circulation within the canopy. This can result in a healthier tree with better fruit production in the long run.
When hard pruning older Citrus trees, it's important to make clean cuts with sharp pruning shears. Focus on removing any dead, diseased, or crossing branches, as well as any branches that are growing too close together. Additionally, thin out any overcrowded branches to allow for better air circulation and light penetration.
After pruning, water and feed your Citrus tree to help it recover and promote new growth.
