Overheated Trees...HELP!

bonsaibegnr79 · Posted: Sat Apr 21, 2007 2:10 pm Post subject: Overheated Trees...HELP!

I have three trees that have major heat stress from being in an enclosed cold frame during warm temperatures.

1) Japanese white pine - candles not pushing, bark becoming wrinkled and needles turning brown.
2) Pyracantha - dropped all of its leaves and bark becoming wrinkled
3) Japanese Maple - buds not pushing, bark becoming wrinkled

I have been misting them whenever I can and all three have some green cambium when you scratch the bark. They are potted in a mixture of pine bark and Permatil (expanded shale). My best guess at this point is to put the in the ground and see if they make it.

I live in the Piedmont of North Carolina and we are experiencing spring like temperatures 70's/40's.

ANY help would be greatly appreciated.

bb79

Stymie · Posted: Sat Apr 21, 2007 2:18 pm Post subject: Re: Overheated Trees...HELP!

I wouldn't have them in the frame bb. The unseasonal temperatures could fry them. Get them out and keep their planting medium moist.

TB420 · Posted: Sat Apr 21, 2007 2:30 pm Post subject: Re: Overheated Trees...HELP!

They should be outside all the time now. I would have them in the shade considering their current condition, and for future reference, get them out of the coldframe once the night time temps get above 20f. That is not to cold for Pines and maples and they can leaf out when they are supposed to for your area. We had a late cold spell here in IN and I had to fill my greenhouse with tree's that were in leaf. When did they start to leaf out? Did you have them in he coldframe once they had broken bud. My Jap maple came from Washington State this spring and the buds were already broken.

Tom

imholte · Posted: Sat Apr 21, 2007 3:26 pm Post subject: Re: Overheated Trees...HELP!

Make sure you are not keeping them too wet, with no leaves they will draw much less moisture. Also refrain from fertilizing them but I would give them a dose of superthrive.

With coldframe/coldhouses you have to becareful, usually I will take the top off of mine if it is not going to be dangerously cold, like below 20f. They will be protected from the wind too, which it the main thing that can kill trees, drys them out since the soil is frozen and no water be used.

One disadvantage of leaving them in too long is they get too warm and in your case get stressed or they start growing too early in the season and suffer from later frosts which can defoliate your trees in one night. I found that out the hard way.

I had maples and pines down to 7F this winter with just wind protection and large pots and they did fine and are growing well this spring.

bonsaibegnr79 · Posted: Sat Apr 21, 2007 5:16 pm Post subject: Re: Overheated Trees...HELP!

They have been out of the cold frame for quite some time (about 1 month). I inspected the roots of all three trees today and there are A LOT of black ones. I planted them in the ground, thinking that the soil would be more evenly moist.

With that much die back in the roots do they have a chance...?

Has anyone else has problems with pots getting too hot killing the roots? And if so is there anything else I can do.

My other pine/maple have all "leafed out" so I assumed the other trees have not since there roots are so heavily damaged.

BB79

BonsaiGuru · Posted: Sat Apr 21, 2007 6:48 pm Post subject: Re: Overheated Trees...HELP!

If it is a tin pan, then the roots will burn, but I don't think anyone uses tin pans anymore

bonsaibegnr79 · Posted: Sat Apr 21, 2007 8:26 pm Post subject: Re: Overheated Trees...HELP!

they are in regular bonsai pots, one of which is a Tokoname.

andycarter · Posted: Sun Apr 22, 2007 12:03 am Post subject: are you sure

forgive my ignorance, could you get the same damage from pests and diseases? in which case different treatments may be required

andy

steve · Posted: Sun Apr 22, 2007 12:44 am Post subject: Re: Overheated Trees...HELP!

Tin pan? Never heard of that one. Where did you get that info?

TB420 · Posted: Sun Apr 22, 2007 2:42 am Post subject: Re: Overheated Trees...HELP!

bb79, where you live you don't need serious cold protection. As Ed says, open the top when the temps get warmer than say 20f. You live in zone 7. You should not need serious cold protection for your trees. Some wind protection if very important in cold weather, but in zone 7 I would probably have it closed for the coldest months Dec., Jan., and Feb. but after that you could probably open the top or remove it completely. On a sunny day that was 30f your coldframe could easily reach 50f+. Last year before my greenhouse was heated, and this year as well on a sunny day, will be about 25-30f warmer than the outside temp., and my GH has a black floor so it would get a bit warmer. I figure that coldframes don't get that warm but I would guess 15-20f. In the winter months when the days are short, less than 12 hours, then they are cold at night longer than they are warm in the day, but as the days get longer and warmer, the coldframe is getting warmer and staying warmer for longer. You say that they have been out for about a month, that would make it mid to late March. They should have been out a month before that, or at least have the top open all the time. If there is a late cold spell like we had this year you can always put them back. I am afraid that the prognosis for your trees is not good at all. As you know black roots are not good. Did you remove the dead roots. I would have just re-soiled them in the same pot's, kept them in the shade, and hoped that they were not totally dead. At least you know for next year. As Ed says, drying winds are very dangerous to a plant with frozen roots. The wind dries the tree out and the roots can't replace the H2O. Just give them protection in the coldest months.
The link is for a couple different solar vent openers, that will open a vent or coldframe lid starting at 60f. Your coldframe could have gotten much warmer than that in early March.

http://www.growerssupply.com/farm/supplies/ProductDisplay?catalogId=10 551&storeId=10001&langId=-1&division