I've only done reveg work with willow and cornus and acorns, and not the type of plants that need sweating. If you are reveging your property and receive a shipment of hardwood whips-cuttings, you may need this technique if you are forecast to have a long, cool spring. Otherwise the typical Joe Homeowner doesn't need this. I doubt this coming spring will be long and cool in most places in the US.

Dan

As I understand it, the technique may be required more because of how the plants were stored (long refrigerated storage) than what growing conditions they are due to experience (long, cool spring) after they are planted. I'd think that the need for sweating does vary some with growing conditions, but the primary factor seems to be storage conditions.

I've helped do this only once, so my memory may not be entirely accurate, but... Trees (whips) were layered on plastic, covered with moist sphagnum, another layer of plastic, etc., etc. Temperatures were maintained at a minimum of 50 and not allowed to go above 70. No direct sunlight. Checked every day. Individual trees removed and potted when the buds began to swell. Redbud, hawthorn and birch were the species, I think. Perhaps others need this treatment as well if they have been in cold storage for the winter. The whole purpose is to force the trees to break dormancy. If it was not done, some trees would no doubt have broken dormancy without the treatment but sweating insures a far greater successful percentage.

Not sure if the instructions are still there, but check Fedco in Maine. They used to have very good instructions for sweating in their woody plant catalog.