Autumn citrus care

We’re lucky to be able to grow citrus in just about every part of Australia and, with new varieties being developed all the time, things in the citrus world just keep getting better. Short of space? Most citrus are now available on dwarfing rootstocks that produce smaller plants (with full-size fruit) that are ideal for pots on balconies or patios. Like to cook? Newly introduced varieties such as yuzu (Citrus x junos) and the related sudachi, plus the more familiar makrut lime (C. hystrix), add flavour to Asian dishes. And if you want perfume, almost all citrus have fragrant spring blooms.

Citrus are great survivors but will always perform better if given good care. This is especially true in autumn when the trees are developing fruit while still coping with pests that built up over summer and facing the coming winter. This autumn citrus care guide will help prepare your citrus for the cold months ahead.

Deal with pests and disease

• Citrus leaf miner Prune off and bin outer leaves that are twisted and etched with wiggly lines (below, left). Spray the foliage with horticultural oil to help clean up the tiny grubs inside the leaves.
• Scale pests Scrub off scales or smother with an oil-based scale spray. Make a note to apply lime sulfur in mid-winter to control white louse scale, which looks like desiccated coconut.
• Stink bugs Wear long sleeves and eye protection when picking off and squashing these large, smelly bugs (below, centre).
• Galls Use a potato peeler to shave the outer layer of lumpy galls in citrus stems (below, right). This exposes and kills the wasp larvae that are creating the problem.
• Sooty mould A black coating on leaves can follow attack by sap-sucking pests. An oil spray will combat the pests, after which the mould will gradually flake off.
• Root rot Poor drainage makes citrus very susceptible to root rot and possible death. If drainage is doubtful, move the tree into a raised bed or well-drained pot.
• Collar rot Patches of flaking bark are caused by poor drainage or overwatering. Clear the loose bark and paint with a fungicide that contains phosphorous acid. Keep soil and mulch clear of the trunk.

Get winter ready

Citrus don’t enjoy the cold, so autumn is the season to prepare them for the coming winter.

• Do a test-watering of container plants to check that water enters the potting mix and drains away freely. Apply a soil wetter, or clear drainage holes if necessary.
• In frosty areas, move portable container plants under cover or against a warm wall.
• Set up protective frames around trees and cover with frost cloth on cold nights.
• Thin out the mulch layer around plants to allow sun through to warm the soil.

Autumn citrus care reminders

• Give individual fruit room to expand by removing excess pieces, leaving just one in each cluster.
• Keep watering the trees as fruit develops. Moisture fluctuations can cause developing fruit to split or drop.
• Harvest mandarins, finger limes and other early ripeners. Pick up and dispose of fallen fruit.
• Prune lower branches that are impeding air movement around the trunk.
• Weed pots, or weed and clear grasses from beneath trees, before spreading a slow-release, organic-based fruit tree fertiliser in early to mid-autumn.
• Apply a soil wetter over the root area, water well and apply an organic-based mulch. Keep mulch clear of the trunk.

Want to know more about growing and caring for citrus? Read our Citrus tree care guide.

Images by iStock