I live in Redmond, WA and I recently noticed that we have been classified as Zone 8A – 8B instead of 7B. Most sources I read state that year-round outdoor planting for Nagami kumquats is recommended only for Zone 8 and above. What is your take on this? I’ve had a Nagami since November, but it has acted differently from what sources I read indicated. I also have a Meyer Lemon that I bring indoors and it did fine over the winter, but the Nagami shed all its leaves within 2 months starting from January. The peculiar thing was that the leaves shed were all green and healthy, leading me to believe it had entered dormancy. It started to grow new leaves in April, but I’m still puzzled why it entered dormancy in indoor conditions even though the less cold-tolerant Meyer flourished.
Long story short, if the Nagami sheds its leaves every winter, will it ever have enough time to produce mature fruit even if it did survive outside?
If you have any particular kumquat or citrus experts you could recommend, that’d be great! Thanks!
According to a local nursery (Raintree), the Nagami kumquat is hardy to 18 degrees, and may produce fruit here. So if we have a cold snap, as we occasionally do, it may be hard on the tree if it’s growing outdoors–unless you can provide it with protection. A friend of mine has grown kumquats before, and they produced fruit, but I believe a long period of subfreezing temperature killed her tree one winter/early spring.
Growing Citrus by Martin Page (Timber Press, 2008) says that kumquats (Fortunella japonica or synonymously Citrus japonica) are prone to zinc deficiency which results in smaller leaves and shorter shoots. They are considered very hardy, but this may be “due to their long winter dormancy.” Nagami grown in a pot will reach about 4 feet, but outside, it can get to 13 feet tall. Fruit is harvested October to January.
It’s possible your Nagami kumquat dropped its leaves because it was entering dormancy, but there are other causes to consider as well. According to the source cited above, leaf drop in citrus trees can be caused by:
- sudden environmental changes (temperature, humidity, etc.)–bringing a plant inside to overwinter is likely to expose it to dry air
- underwatering (don’t overcompensate by watering a leafless plant because it has no way of transpiring the water without its leaves; prune it the next spring by reducing shoots by about a third of their length)
- overwatering (make sure container drains well; soil that doesn’t drain well can lead to yellowing leaves and leaf drop)
You may want to speak to a local expert at the Western Cascade Fruit Society, or the Home Orchard Society.
Also the nurseries that specialize in fruit trees are good resources:
Raintree