When to prune kumquat trees?
- Botanical name
- Citrus japonica
- Family
- Rutaceae
Kumquat trees are pruned from May to August.
Kumquat trees are woody perennials. The edible part is the fruit.
The kumquat cannot be trusted to survive a winter outdoors, so where the season turns cold it is never set in open ground. In autumn the pot moves to a room that stays above 7 °C, and watering there is less frequent than in summer in the garden.
The fruit of a kumquat is eaten with the skin.
Kumquat trees through the year
- pruning
In short
Growing conditions
Pests and diseases
Listed here is every problem for which the sources name this plant as a host. The problems are not listed in order of how common they are.
- Signs
- Colonies of small aphids sit on the shoot tips and the underside of the leaves. The leaf curls and puckers, and sticky honeydew is left on everything below. The viruses they carry are more dangerous than the feeding itself.
- Prevention
- Go easy on nitrogen, because soft sappy growth is what aphids are looking for. Encourage the predators (ladybirds, lacewings, parasitic wasps). Use a reflective mulch, which puts them off settling, and a strong jet of water to knock the colony off the tips.
- What to do
- Potassium soap works on contact and only while it is wet, so it has to reach the underside of the leaf. On drought-loving plants and in heat it can scorch, so apply it in the evening.
- Signs
- Flecks of white waxy wool in the leaf axils, along the leaf sheaths and in other sheltered corners of the plant. Under them sit soft pink bugs and orange eggs. The plant is sticky with honeydew, black sooty mould grows over the leaves, growth stalls and the leaves may drop early. Some species live on the roots and show up only at repotting.
- Prevention
- The females neither fly nor walk far, so you nearly always bring them in with a new plant: check the leaf axils when you buy and keep a new plant apart from the collection for a while. Clear away dead leaves and prunings as they appear, because the eggs are on them. A plant will take a few mealybugs. A badly infested one is often cheaper to throw away than to rescue. In a greenhouse the predators hold them down, the ladybird Cryptolaemus and parasitic wasps, which work in the warm half of the year.
- What to do
- The waxy coat repels the spray, so potassium soap has to reach exactly the leaf axils where the bugs sit, and a single application is rarely enough. Single nests are easiest to take off with a cotton bud.
- Signs
- Scale like bumps stuck to the stem and the underside of the leaves, on the indoor species preferably along the midrib. They do not move and are easy to overlook as part of the plant. The soft scales give off honeydew, so the leaves turn sticky and blacken with sooty mould. In a heavy attack the growth falters.
- Prevention
- As with the mealybugs: the adult females do not fly, so they arrive with a new plant. Check the stems and the veins on the underside of the leaves and keep a new plant apart for a while. A healthy, well kept plant takes the odd scale and action is not always needed. Put a plant that may go outdoors in summer outside, because cooler air and the predators do more than spraying.
- What to do
- An adult scale is protected from the spray under its waxy shield, so scrape it off with a fingernail, a cloth or an old toothbrush while there are few of them. A badly infested house plant is often better thrown away than treated.
- Signs
- Small pale dots show over the upper side of the leaf, with a generally faded look. In a heavy attack the leaf browns or yellows and the plant dies. When it gets worse, a fine web is visible between the leaves.
- Prevention
- Most at risk are the plants that stand in the dry air of a room all year. Mist regularly and raise the air humidity to lessen the trouble. Keep new plants apart from the others for a few weeks.
- What to do
- On sturdy plants wash them off thoroughly with water first. Then potassium soap, which works on contact and has to reach the underside of the leaf.
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Related plants
The plants below are in the same botanical family (Rutaceae).
Sources about the plant: Clemson Cooperative Extension, GBIF Backbone Taxonomy, NC State Extension Plant Toolbox, Royal Horticultural Society, Wikidata. Checked between 14 and 28 August 2026. The problem descriptions also draw on: EPPO Global Database, University of Wisconsin-Madison Division of Extension, Utah State University Extension.