Ok some time ago I mentioned I was going to plant various varieties of cold hardy citrus in my zone 5 or 6 habitat. I have planted them in 2 lots (parts of the yard). Lot 1 is on the south side of the house and on a small hill. In this area I planted a satsuma and kumquat and also stored 5 or so potted citrus to see how they would do compared to the ones in my home. The 2 pictures are taken from the lot 1 area.




The coldest these trees saw was 35 f. They recieved quite a bit of love and were covered with plastic and blankets. We had a pretty good snow cover which helped. It was -3 f at the coldest pointn this winter....

My lot2 citrus were younger trees and did all survive, They did have some leaf drop due to exposing them the sun with soi temps in the high 30's f. I assume if the tree is still green then it is alive?

Any comments are appreciated.

Frank

Frank you've done well. These trees should double in size for you this summer. Be prepared to increase the size of your protection every year, as citrus can produce rapid growth in a single season.

Frank, it has been interesting following your posts for the last year. You are certainly a Mass. citrus pioneer. My guess the tree on the south side of your home would be a zone or two higher. - Millet

I congratulate you on your success. I do have one suggestion that might help with the leaf drop--shade screen. I kept my citrus seedlings including key lime, lemon and orange outside for most of the winter. Initially I was bringing the key lime inside when night temps were dropping below 40, but as winter went on I got secure in my feeling that the sun screen was working on all the seedlings and left them out when temps dropped to the low 30s. I did not only not have leaf drop, I got growth on most of them in the middle of winter.

I am convinced that the sun screen prevents heat buildup on the leaves when the roots are inactive, but with the black pots on warmer days the roots warm up enough to support growth.

so Burlap would work for a shade screen?

I am picking the kumquats now..

thanks!
Frank

That would probably do. Citrus only need about 650 PAR units which is about 1/3 full sun. For preventing winter leaf drop, I think it works by limiting the area on a leaf that is getting direct sun to tiny spots so that the leaf can dissapate the heat. As cold as the ground is there, you probably will not get growth in winter, but this will keep the leaves from getting overheated.

Thanks, I think 3-4 layers of 2 mil plastic must cut down on the sun exposure also.....

I am always interested in any other suggestions

Frank

Actually, if your trees are going completley dormant they do not need much sun at all. Some people in cold climates actually store container citrus in a cold dark basement for the entire winter.

I'm sure you are right about the plastic cutting down on the sun intensity, but if you are still getting WLD, it is probably not enough.

Interesting enough (at least to me), I stored some potted citrus (inc a Meyer) and they did great with no leaf drop in the winter.

At the begining of the spring I didnt realize that 1 of my heater cables wasnt working and that the soil was around 40, This with some (minor) sun exposure might have done the tree in. It was a 10 deg tangerine that I got from Stan.............This one puzzles me as it looked great in early March....

In an enclosed environment, sun can build up enough heat on a leaf to kill it fairly easy if the roots are not functioning (below 55F)--cold hardiness does not matter here. If the stems are still green, it may come back.

quick question, if a tree was in the dark/severe shade, had cold roots and was exposed to sun. would that kill it?

Thanks

It might not kill it, but it would have some serious damage. Two things--when citrus trees have been out of the sun for a good while, it is always better to introduce them back to sun slowly to prevent sunburn.

Second, anytime citrus trees are exposed to direct sun while the roots are below 55F (even 60F) they can experience leaf drop due to the fact that the leaves will overheat--sometimes this leaf drop will occur for weeks after the exposure.

"That would probably do. Citrus only need about 650 PAR units which is about 1/3 full sun. For preventing winter leaf drop, I think it works by limiting the area on a leaf that is getting direct sun to tiny spots so that the leaf can dissapate the heat. As cold as the ground is there, you probably will not get growth in winter, but this will keep the leaves from getting overheated"

thanks Skeeter, Strangly enough I did get some very minor growth in Feb on my satsuma. As the citrus is covered by at least 4 layers of plastic, I though that the sun intensity would be fairly low anyway....

where would I get the sun shade stuff you reference

Down here many of the big box stores carry it-- HD--Lowes. It comes in rolls-- I believe mine is 6 ft x 25 ft. Many nurseries use it so you may find it at places that supply nurseries.

well with nights in the 20's it is time to start to winterize my citrus. I have been breaking out the plastic and blankets. I will have to take some pictures showing the growth.

I currently have green satsumas, green meyer and 2 thom citraquats for fruit.........with now 13 trees in the ground.

Frank