Can you tell me what my hardiness zone is?
The best way to find your hardiness zone is to go to the USDA Plant Hardiness Zone Map page and enter your zip code in the "Find your hardiness zone" lookup. While the hardiness zone is a good indicator of whether a plant will overwinter successfully, some plants require good drainage and may not survive without good drainage. Delosperma nubigerum is a good example. It is hardy in zone 6 - 9, but will not survive without good drainage.
Espaliered fruit trees should not have hardiness any different from fruit trees grown out in the open, unless the espaliered trees are up against a heat -absorbing wall such as a stone wall. If the wall is facing south or west, it will absorb heat and radiate some of it into the soil, increasing the hardiness of the site. This is usually referred to as a microclimate.