Is Prickly Pear Cactus deer resistant?

The one cactus that genuinely works in the northeast, and it is native here: eastern prickly pear grows wild on Cape Cod, Martha's Vineyard and the sandy coastal plain. Deer leave it alone for obvious reasons, and the spines are the least of it. The real defense is the glochids, the hair-fine barbed bristles at each spine cluster, which are worse to deal with than the spines themselves. Wear leather gloves and long sleeves when planting.

Cold is not what kills it. Winter wet is. It will take minus 25 in sharp, gritty, sand-heavy soil and rot in a season in ordinary garden loam. Site it on a slope, a raised bed, or a gravel scree facing south. Do not amend with compost and do not mulch it.

Expect it to look dead from December to March. The pads dehydrate deliberately, shrivelling and flopping flat to the ground so ice cannot form in the tissue. They plump back up in spring. Every year someone digs one up in February assuming they lost it.

Note that the Rutgers rating covers cacti generally, at family level. Do not read it as applying to the tender desert species sold as houseplants: those are zone 9 and warmer and will not survive a New England winter outdoors.