Hi!
I'm Jordan, from Italy. Nice to meet you. I have a question about a yuzu plant I bought this January.
The plant had a small flower and many dark green leaves when arrived at home. Few days later I repotted the plant with a specific, slightly acidic, soil for citrus and left it indoor. One month later I spent 10 days in Japan and when I come back the yuzu had three new branches but dropped the flower, than I decided to move the plant outside. The last month was windy and the temperatures 10 ⁰C above the average (~27⁰C) and the yuzu seemed to have stopped thriving, the leaves were a light green. I was afraid that I've watered too much so I repotted again with new soil but the old soil was moist, not wet, and hadn't a mushy smell. Anyway, in these days we have temperature 10 ⁰C below the average (~5 ⁰C overnight), it's raining a lot and my yuzu have lost many leaves as you can see in the pics. I saw some spider mites and I killed them with my fingers and by using permetrine, I gave 1,5 liters of water to the plant every 10 days, once with iron sulfate, and I fertilized the soil with a product for citrus.
What's your opinion? I made some mistakes or the plant is only under stress?
Thanks.

The amazing part is your yuzu is still alive and not looking that bad.

Stop fertilizing! Read the bag to check if the potting soil you used had fertilizer already in it. Starting NEXT spring, fertilize every other month with a citrus specific fertilizer. You won't need to add anything extra. Mix it at 1/2 the recommended strength.

Stop repotting. Two times in 3 months is a lot of stress to put a plant through. A new environment is more than enough stress. I would not expect the flower to stay and if it did, I would not expect the fruit to stay on the plant to maturity.

Next time you have an insect problem, use Insecticidal soap or alcohol, then rinse the plant well. Those choices will kill the bugs but are kinder and gentler on the tree and also the environment.

Don't water on a schedule but rather when the top couple cm of soil is dry. Then water enough to allow water to drain out the bottom of the pot.

Are you planning to keep it in a pot? If so, start planning for its future. Find the graft (I suspect its where the trunk splits into 2 branches). Every new branch at or below the graft needs to be cut off. If the rootstock is a Flying Dragon citrus, it will be easy to tell what should come off as Flying Dragon has a 3 part leaf. Also, check the other new branches - they grew so fast, I suspect they are water sprouts. Water sprouts grow straight up from a branch and sometimes have different looking leaves (but not always). They also need to be removed.

Now decide on shape and size and prune to maintain that. Your tree will grow new leaves and be fine. Good luck!

PS: Yuzu is one of my favorite citrus.

Lucy68 said:The amazing part is your yuzu is still alive and not looking that bad.

It's nice to read that. 😅
I thought I would see the plant slowly die.

Lucy68 said:Stop fertilizing! Read the bag to check if the potting soil you used had fertilizer already in it. Starting NEXT spring, fertilize every other month with a citrus specific fertilizer. You won't need to add anything extra. Mix it at 1/2 the recommended strength.

I added a bit of urea and a specific citrus fertilizer, both slow release, although I used an already fertilized professional soil for citrus.

Lucy68 said:Stop repotting. Two times in 3 months is a lot of stress to put a plant through. A new environment is more than enough stress. I would not expect the flower to stay and if it did, I would not expect the fruit to stay on the plant to maturity.

I know, but I was afraid to lost the plant. However, as I said, the plant wasn't overwaterd, although the moisture indicator said the soil was wet (I bought it on Amazon for few euros, so I think it doesn't work really well).
I don't expect to see new flowers or even some fruits this year. First of all I want a healthy plant. 😁

Lucy68 said:Next time you have an insect problem, use Insecticidal soap or alcohol, then rinse the plant well. Those choices will kill the bugs but are kinder and gentler on the tree and also the environment.

I used a permethrin insecticide which is allowed in organic agriculture. I used it once in late evening to avoid to kill bees or other pollinators.

Lucy68 said:Don't water on a schedule but rather when the top couple cm of soil is dry. Then water enough to allow water to drain out the bottom of the pot.

Yes, I'll do it. We had tre days with 27 ⁰C, full sun, and now it's cold, rainy and the top of the mountains are covered with snow. Weather changed rapidly.

Lucy68 said:Are you planning to keep it in a pot? If so, start planning for its future. Find the graft (I suspect its where the trunk splits into 2 branches). Every new branch at or below the graft needs to be cut off. If the rootstock is a Flying Dragon citrus, it will be easy to tell what should come off as Flying Dragon has a 3 part leaf. Also, check the other new branches - they grew so fast, I suspect they are water sprouts. Water sprouts grow straight up from a branch and sometimes have different looking leaves (but not always). They also need to be removed.

Yes, I'll keep it on a pot, like a plant of lemon and a prunus mume.
Ok, I'll prune the plant better.

Lucy68 said:Now decide on shape and size and prune to maintain that. Your tree will grow new leaves and be fine. Good luck!

Nice. 👍🏻

Lucy68 said:PS: Yuzu is one of my favorite citrus.

I love every plant that give delicious fruits. I have 600 plants of blueberries and 200 of blackberries. 😁