AusBonsai

Good day everyone,

I’ve had two maples (buergerianum and palmatun) for several years now. I bought them as bonsai starters and now they have grown into little trees with sizeable trunks.
However, they seem to have just one spurt of growth in spring and that’s it. Hardly any new buds or leaves thereafter. So all those leaves go through wear and tear of early Sydney summer and by the end of December the trees don’t look happy at all.
I was wondering if it is a normal growth pattern for maples or it is me doing something not right.
I have them in a mixture of mulch and diatomite in wide shallow pots (about 15 cm deep), I fertilize fortnightly and water regularly (I mean every day on hot days and every other day if it is not too hot). I don’t have a backyard so I keep them on my balcony under the shade (may be not enough of it I admit).
Any advice or information would be much appreciated.

Down here all my maples grow all spring and into the summer. I'm still pinching new shoots now and expect to keep doing so for another month. even so, by March the leaves will look a bit sorry unless I defoliate to get a new batch for autumn shows or better autumn colour.

15cm deep pots is quite deep for bonsai and I would not describe those as 'shallow'. Maybe you mean 1.5cm or 15mm deep? I have used really shallow pots like that in the past but the maples don't like them much. Mine are doing much better in slightly deeper pots. I guess they hold moisture better.
I also water twice each day - morning and evening but how often they need water will depend on other factors like how hot it gets and what sort of potting mix is used. My mix is quite open using 4-6mm particles.Not sure what the 'mulch' component of your mix is or what size it is.

I'm not sure that shade will stop the trees growing though it may limit their energy intake and thus allow less growth???

What about repotting? Nearly all of my trees begin to slow in growth and look poorer the longer they are left. After repotting they always grow better and look healthier.

My maple will shoot new growth all summer, they slow down after spring, but a good defoliate will get a new flush of growth at the end of Jan / Mid feb to have fresh leaves to colour up in autumn (if I am lucky)

Ken

You are not feeding anywhere near enough for a developing tree. If using only liquid, (not recommended) at least twice a week, preferably 3 times. You should be able to defoliate tridents at least twice and palmatums once.
Feed them more and give them more light as well. Shade only if it's really hot and then only 50%.

I'd be interested to see a picture of the leaves currently?
My maples tend to get redish leaves (almost like an early autumn onset) and don't seem to grow all that well either.
Perhaps as Treeman suggested our issue is underfeeding?

Thanks for your replies.
I'll try more feeding and defoliation. Hope it will help.

Kvanto.

One should only defoliate a healthy tree.
I don't believe the advise above was to defoliate your tree it was more talking about regime's that others incorporate for healthy vigorous trees.