AusBonsai

Hi folks,

Just a question- can you trick a Japanese maple into going red in summer like it does in autumn just by putting it in shade or is it because of lack of feeding?

Thanks,

Brad.

stick it in the fridge

Hi Brad,
I'd think that would mess with the natural rest, grow, recycle life cycle, and could potentially weaken your plant.
In short, I'm not sure if it can be done..


Cheers
EZ
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Ummm yes, it could be done, I personally wouldn't.
As aforementioned, the low temperature could bring on autumn colour.
Why not wait till autumn.

I'm pretty sure that trees colour up in response to cold. When the temps hit a trigger point the tree stops sending food to the leaves and withdraws all the useful stuff from the leaf. Whatever is left is waste that the tree does not need and it is this that provides the colour we see.

SO... putting the tree in the shade will not trigger autumn colour, Withdrawing feed will not trigger autumn colour either (until the tree gets so starved it is close to dieing then it may withdraw all good stuff and drop leaves in an effort to survive)

I read somewhere that cold temperatures had nothing to do with autumn colour....but was a health issue. The healthier the tree.... the better the colour. Not sure I agree....just putting it out there.

Hi Bonsai peeps,

Thank you for your replies. I now know where to start my biology investigations.

Cheers,

Brad.

It's not just cold I don't think. It's also to do with the amount of daylight hours the tree receives. I don't mean sun vs shade, but day vs night. There are less daylight hours in winter and that with the temp drop causes some response from the tree. I've heard people out their trees in the fridge and the leaves just dropped rather than changing colour.


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It's mainly the cold, from my experience. Whatever the day lengths are doing, it's when the cold weather bites that the leaves start to turn colour. If you've defoliated, and the leaves are younger and fresher it will take them a bit longer to colour up.

I think by the time you've left the tree long enough in the fridge, it hasn't seen the sun, no photosynthesis, may well be on the way to dead. Be patient.

Gavin

Hi

I definitely agree with Shibui (Neil's) comment.
I had autumn colors while air layering my trident, j.maple and plum trees.
Once roots developed to a sufficient amount, they all went back to green.


Hope this helps.

Hi Dennis,

Interesting info about the effect of layering on leaf colour; I hadn't considered it.

Thanks,

Brad.

Hi Guys,

this should go some ways to expaining it for ya

http://www.sciencemadesimple.com/leaves.html

Bonsaitrees wrote:Hi Guys,

this should go some ways to expaining it for ya

http://www.sciencemadesimple.com/leaves.html

Hi artists,

A fella on the Internet bonsai club (IBC) forum reminded me of something from my year 12 horticulture class- senescence which is the scientific process for leaf colouring. He added that premature colouring was a sign of stress and that the standard Japanese maple (a.palmatum) goes red in full sun but stays green in shade which is what mine has done. I have it sitting beside the pool on concrete pavers so it is likely with the bright, high UV days and the heat of summer the tree was under stress. About a month ago I moved it into the shade and increased the watering cycle and it has now gone almost green. The bark varies in colour from raspberry red to gold down by the root flare so that colour might be a sign of stress also.

We'll see how it holds up after its last summer feed- maybe some seasol.

Cheers all,

Brad.