Acer palmatum can produce both adult and juvenile foliage forms. Adult foliage is the typical pattern you see on any named cultivars. But the trees can often put out new growth during the season, often on long whippy shoots, that will have juvenile or very distinctly different looking foliage, usually less lobed and quite a bit larger. How you deal with these shoots is kind of the gardener's choice - many choose to head them back - but if left alone, the foliage they produce next season will appear "normal" or be your typical adult foliage.

Containerized JM's are at risk for cold damage when temps drop below the mid 20's (around -4C). The top growth will be fine to much lower temperatures but the root system can be damaged at this level of cold - no insulating layer of soil mass in a container like the trees would experience in the ground. How likely any damage is to occur depends on both the duration of the cold spell as well as the size of the container. A large container will be at less risk than a smaller one with less soil. Wrapping the pots with bubble wrap or clustering all the containers together (creating a temporary microclimate) is usually sufficient protection in areas where this level of cold is only a short term situation - just a couple of days at most. A longer period of very cold weather may call for some more sophisticated manner of protection, like moving the containers into a shed or garage. Lifting or raising the pots is actually counterproductive, as it allows cold air to completely surround the container. Best just to leave on a solid surface.

Thanks as always Gardengal for that Sound advice..Regards

Stephen,Cheshire,UK