Round Kumquat
Citrus Japonica
Citrus Japonica, commonly known as the Round Kumquat, is a delightful citrus plant prized for its sweet, edible fruit and attractive foliage. Originating from East Asia, it is often grown for its ornamental value and is suitable for both indoor and outdoor cultivation.
Everything it needs
9 essentials at a glance
Watering
Citrus Japonica prefers consistently moist soil but should not be waterlogged.
Water every 1-2 weeks, allowing the top inch of soil to dry out between waterings. In the growing season (spring and summer), increase frequency to once a week. Signs of over-watering include yellowing leaves and root rot, while under-watering may cause leaf drop and wilting.
Light
This plant thrives in full sun, requiring at least 6-8 hours of direct sunlight daily.
Ideal placements include south or west-facing windows. While it can tolerate partial shade, insufficient light will result in poor fruit production and leggy growth.
Soil
Citrus Japonica prefers well-draining soil with a pH between 6.0 and 7.0.
A mix of potting soil, perlite, and sand is recommended to ensure proper drainage. Avoid heavy soils that retain too much moisture, as this can lead to root rot.
Humidity
This kumquat thrives in moderate to high humidity levels, ideally between 40-60%.
To increase humidity, consider using a pebble tray with water or a humidifier. Signs of low humidity include browning leaf tips and leaf drop.
Temperature
Citrus Japonica prefers temperatures between 60-75°F (15-24°C) and is hardy in zones 9-11.
It can tolerate brief periods of cold down to 30°F (-1°C) but should be protected from frost. During winter, keep it indoors if temperatures drop significantly.
Fertilizing
Use a balanced fertilizer with an NPK ratio of 10-10-10 or a specialized citrus fertilizer.
Fertilize every 4-6 weeks during the growing season, and reduce frequency in fall and winter. Signs of nutrient deficiency include yellowing leaves (nitrogen), poor fruiting (phosphorus), and leaf drop (potassium).
Pruning
Prune Citrus Japonica in late winter or early spring before new growth begins.
Use sharp, clean pruning shears to remove dead or crossing branches and to shape the plant. Deadheading is not necessary, but removing spent fruit can encourage new growth.
Repotting
Repot every 2-3 years or when the roots become crowded.
Choose a pot that is 1-2 inches larger in diameter. Signs it needs repotting include roots growing out of the drainage holes and stunted growth. To repot, gently remove the plant from its pot, loosen the roots, and place it in fresh soil.
Propagation
Propagation can be achieved through stem cuttings or seeds.
For cuttings, take 4-6 inch sections from healthy stems in spring, dip in rooting hormone, and plant in a well-draining mix. Keep the soil moist and in a warm location until roots develop. Seed propagation is slower and less reliable.
When it's unhappy
Yellow leaves
Why it happens
Usually caused by over-watering or nutrient deficiency.
How to fix it
Check soil moisture and adjust watering schedule. Fertilize with a balanced fertilizer if nutrient deficiency is suspected.
Fruit drop
Why it happens
Can occur due to stress from temperature changes, inadequate light, or over-fertilization.
How to fix it
Ensure stable temperatures, adequate sunlight, and avoid excessive fertilizer application.
Leaf drop
Why it happens
Often a result of sudden environmental changes, such as moving the plant or changes in humidity.
How to fix it
Maintain consistent care and avoid sudden changes in the plant's environment.
Pests (e.g., aphids, spider mites)
Why it happens
Pests can infest the plant, especially in dry conditions.
How to fix it
Regularly inspect the plant and treat infestations with insecticidal soap or neem oil.
Root rot
Why it happens
Caused by over-watering and poor drainage.
How to fix it
Allow the soil to dry out and improve drainage. If severe, repot the plant in fresh, dry soil.
Care through the year
Spring
In spring, resume regular watering and fertilizing as the plant begins active growth. Prune any dead or crossing branches to encourage healthy growth.
Summer
During summer, ensure the plant receives full sun and monitor for pests. Water more frequently as the soil dries out faster in warm weather.
Fall
In fall, reduce watering as the plant's growth slows down. Begin to prepare it for winter by bringing it indoors if temperatures drop.
Winter
In winter, keep the plant in a warm area with plenty of light. Water sparingly, allowing the soil to dry out more between waterings.
Toxicity & Safety
Citrus Japonica is generally non-toxic to pets and children. However, ingestion of large quantities may cause mild gastrointestinal upset. The fruit is edible, but the seeds can be a choking hazard for small children.
Good to know
How often should I water my Citrus Japonica?
Water your Citrus Japonica every 1-2 weeks, allowing the top inch of soil to dry out between waterings. Increase frequency during the growing season.
What light conditions are best for my kumquat?
Citrus Japonica thrives in full sun, requiring at least 6-8 hours of direct sunlight daily for optimal growth and fruit production.
Why are the leaves on my kumquat turning yellow?
Yellow leaves can indicate over-watering or nutrient deficiency. Check soil moisture and consider fertilizing if necessary.
Can I grow Citrus Japonica indoors?
Yes, Citrus Japonica can be grown indoors as long as it receives sufficient sunlight and is kept in a warm environment.
What is the best fertilizer for kumquats?
A balanced fertilizer with an NPK ratio of 10-10-10 or a specialized citrus fertilizer is ideal. Fertilize every 4-6 weeks during the growing season.
How do I propagate Citrus Japonica?
You can propagate Citrus Japonica through stem cuttings or seeds. For cuttings, take healthy stems, apply rooting hormone, and plant in a well-draining mix.
What should I do if my kumquat is dropping fruit?
Fruit drop can be caused by stress from temperature changes or inadequate light. Ensure stable conditions and adequate sunlight to minimize this issue.
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