Trident Troubles

abellows

Soltan,
Consider the possibility that these are not trident maples, but instead Montpelier maples (Acer monspessulanum). They look very similar (exactly like yours) to tridents, but the lobes are a bit more rounded and the leaves a tiny bit thicker. If this is the case, Montpelier maples have very different needs than tridents--they like it dry and hot. I have about a dozen of them, and in my first year, they did the exact sample thing.
Sorry about the lousy photo--Ijust snagged it off the internet.
Scott

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soltan

I think for now I will put it down to poor roots/ growing medium.
I will be looking for some better growing medium before spring and make sure I fertilise well to ensure good root growth.
I am alittle extra stressed at the moment I spose because I am going away for about 5 days and my trees will be in the hands of the nieghbor. Enough to make any bonsiast shiver .

abellows
I have often wonderd wether I had jumped the gun in calling these seedlings trident maple, but the more I look at them the more I believe they are trident. I did a google serach on the maple you mention and I did not find a match.

Thanks to all for your help. I hope I can post some pics this time again next year with lush green leaves.

__________________
GROW DAMIT!
BRETT AUSTRALIA ZONE 8-9?

rockm

That's sun scortch, not soil problems. Direct sun will do this. Hot roots add to the problem, especially if nighttime temperatures don't get much below 70 F.

ALDEVAUX

Leal scorch or tip burn have exactly the same physiological causes :
1 -Direct sun on the leaves can make them transpire more if the roots cannot supply the needed amount of water to prevent the tissues from dying.
2 - Too much salt concentration in the soil, or not enough feeder roots to absorb the required amount of water needed by the leaves, will also cause the same dying of leaf tissue.
If it was only a problem of direct sun, the seedlings that are in the ground in the same hot house will also have leaf scorch.

SiNguyen

Hi everyone, I had the same problem in my maples too, eventhough they were in full or partial shades at the time. I have to agree with Aldevaux and Soltan on this problem. The heat and dry winds and direct hot sun light are major contributing factors, but the main culprit is the poor root system, which is usually due to a combination of poor draining soil, salt build-up, and lack of nutrients and micronutrients. Perfectly healthy trees should not develope leaf burn in the sun.
Trident maples should be grown in full sun in order for them to develop quickly, especially if they are small seedlings or pre-bonsais, so putting them in the shade will slow them down unnecessarily. For "finished" bonsais, the full sun will allow for smaller leaves and shorter internodes and a deeper red foliage color in the fall.
To Soltan, I would suggest repotting the burnt trees in larger containers with a free-draining mix (like with 95% pumice), then water frequently and fertilize routinely and slowly expose them to full sun light outside of the hot house. Using filtered water is good too, like that used at the professional nurseries, but is not neccessary if the trees are rountine repotted every 3-5 years in order to remove the old soil and salt buildup. (By the way, I am not convinced that drenching or "flushing" the pot would remove the salt build-up in potted plants, although this has been taught for a long time.) I think repotting and replacing the old soil is the only way of removing salt- build-up in a pot. For me, when my trees start to get leaf scorch at the tips, I start to plan for repotting, whenever it is appropriate (usually from February to August, for me in Southern California). Keeping the pots shaded and cool in the summer is good too. Wish you Ozzies some rain soon!
Si

ALDEVAUX

Yes, SiNguyen, this is a good and detailed explaination of the tip burn disease problem and the measures needed for its control.
However, concerning the drenching of the potted tree to remove the built up salts, you definitely need a very well draining substrate and the use of lots of water. I was able to reduce the salinity of some of my potted bougainvilleas that were growing in approx. 1 liter pots from 5 millihos/cm to less than 2 millihos/cm by using more than 5 liters of water for the drench, making sure that all the water came out of the drain holes. When the substrate does not drain very fast, the procesus takes a much longer time because it takes more time for the water to get to the bottom of the pot and has sometimes to be repeated two or three times to get most of the salts out. Furthermore, if the pot contains fertiliser pellets, they should be preferable removed before the start of the drenching.

SiNguyen

Hi Aldevaux, I agree with you, I should have said that drenching would only work if you have a very well-draining soil mix. If the soil is bad or compacted and don't drain well, then drenching it regularly could really make the problem worse. I have also seen people take compacted and pot-bounded maple trees out of the pot and immerse the root ball in water for 1-2 hours, once a week for a couple of weeks, and also clean out the inside of the pot, in order to leach out the salt. This technique is supposed to be effective but I have never done it so I can't vouch for it.

For hot climate, like in Southern California, keeping the maple bonsai pots on top of a cool gravel tray is also very good too, because as the root tips poke through the drain holes, they won't get blasted by the hot-drying air. Because if the root tips get burned, the leaf tips will scorch too. I just keep most of my bonsais on the ground in a gravel planting bed in the summer. They seem to be alot happier than beeing on the high benches.

BTW, Aldevaux, you really know your chemistry!
Si