Fruit in Pots: Lemon

Last fall, the warm weather stayed late into October, and I made the mistake of leaving my potted Moro Blood Orange outside too long. One cold night was all it took to kill the grafted portion of my 3 year old orange tree. The cold-hardy roots may still be alive, but we won’t find out until spring when I put it in the sun. If it lives, I’ll no longer have a Moro, but probably a Flying Dragon, or Trifolate orange. This might make for an interesting bonsai.

Why is my Meyer Lemon dropping leaves?

But anyways, when my healthy Improved Meyer Lemon started shedding leaves all over the place a few weeks ago, I got scared.

Losing all its leaves.

Losing all its leaves.

I did some research and found out what was going on. In the summer, lemons develop an extensive root system that can support the tree during the darker winter period. In the winter, the plant remains evergreen, but is somewhat dormant.

During this dormant time, if the plant is exposed to too much sunlight, it will shed leaves because it does not need the energy, and because the leaves can burn when dormant. To prevent damage, the lemon tree will drop leaves, sometimes all of them if the light is very bright.

I made things worse by placing this tree in a very bright west-facing window, and kept the house rather cool, increasing the plant’s dormant state.

Proper winter care of potted orange and lemon

These are the things that I’ve learned:

  1. Bring citrus trees in the first time night temps drop below 45F. Even if an orange or lemon tree is “hardy” weather in Zone 4-5 can change rapidly and it only takes a few hours to kill a plant.
  2. If your house drops below 70F (even at night) place trees out of direct or indirect sun. Don’t put trees in a window, ambient indoor light is plenty.
  3. Water plants when soil feels dry, usually about once a week. Don’t over water. A couple times during the winter, thoroughly soak and let water drain from the pot to leach out salt.
  4. Investigate other causes of leaf drop. Insects are a common problem indoors. Monitor for flies, scale, and mites. Rinsing plant in the shower or neem oil spray are effective control measures.
  5. Wait. Leaf drop from too much sun won’t kill your plant.

Recovering from leaf drop

Continue to care for your barren tree, and once leaf drop has occurred, don’t move your plant to a brighter or darker area of the house. It’s trying to adapt to the light where it is.

It's alive!

It’s alive!

Three weeks after all but about 6 leaves fell from my tree, I noticed that my Meyer Lemon was covered by tiny flower buds all over, next to the leaf nodes.

A week after that, new leaf buds appeared. Through all this, my tree didn’t lose the single lemon it’s had since the summer. Next year, this tree won’t be getting my prime window space.

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