Cumquat leaf yellowing

[Daluke]

I’m pretty new to the world of citrus / cumquat for bonsai.

I’ve had consistent yellow leaves (not deformed) and poor new leaf growth on a purchase from several months ago.

I repotted into a more open mix (it was in super water logged soil), have been treating with iron chelate and haven’t noticed any real change. Fruits are consistent.

Does anyone have any idea on how to promote healthy growth?

[evan]

Mine have only just woken up from winter and some are still yellow with only very small signs of movement. The yellowing is unavoidable unless you shade them them over the winter (even better if it's shaded and also in a greenhouse).

Might need to up the fertiliser. I use a citrus slow release for mine with good results.

Other than that only thing to do is wait, they really need the warmth to begin pumping the growth.

[KIRKY]

All citrus are gross feeders, they need feeding all the time. Full sun food and water are the go for healthy trees.
So I would suggest your tree is probably starving. The other problem that will cause yellow leaves is over watering.
Slow release foods are fine when the trees are healthy and well feed continuously. Other wise a hungry tree has to wait for the warmer weather for the slow release to break down enough to start the feeding cycle.
Suggest you get some citrus organic food that will start feeding as it breaks down in a couple of weeks and while your waiting for that to kick in a liquid feed weekly, till you get the desired green leaves. I believe Powerfeed have a citrus specific liquid fertiliser.
Cheers
Kirky

[Daluke]

All citrus are gross feeders, they need feeding all the time. Full sun food and water are the go for healthy trees.
So I would suggest your tree is probably starving. The other problem that will cause yellow leaves is over watering.
Slow release foods are fine when the trees are healthy and well feed continuously. Other wise a hungry tree has to wait for the warmer weather for the slow release to break down enough to start the feeding cycle.
Suggest you get some citrus organic food that will start feeding as it breaks down in a couple of weeks and while your waiting for that to kick in a liquid feed weekly, till you get the desired green leaves. I believe Powerfeed have a citrus specific liquid fertiliser.
Cheers
Kirky

How much feed you reckon?

My usual regime is every 2 weeks from mid growing season.

Power feed and thrive is the strongest chemical I have… up it to once a week?

[KIRKY]

How much feed depends on the size of the pot. While it’s got yellow leaves I would liquid feed every time you water.
Powerfeed or Charlie is fine. Generally citrus likes feeding all year round in the garden so in pots being watered all the time you can do the math it’s hungry.
I’d feed it the same amount you feed your other bonsai’s in the same sized pots, plus the extra liquid feed until it starts to green up.
Then maintain with either slow release remembering it really only works in the warmer weather. Or other organic fertiliser suited for citrus as most will have all the mineral trace elements require for healthy citrus.
Cheers
Kirky