According to Gray's Manual of Botany, the most common species of prickly
pear in the US, Opuntia humifusa, has a native range from Massachusetts
west to Minnesota, south to South Carolina, upland Georgia, Alabama,
Mississipi, Missouri, and Oklahoma. Opuntia tortispina (which has
twisted spines) grows from Colorado and New Mexico east to Wisconsin,
Ohio, and northern Kentucky. O. macrorhiza grows from Texas to Kansas
and SW Missouri, and O. fragilis grows from Eastern Manitoba to British
Columbia, south to Illinois, Iowa, Kansas, NW Texas, and Arizona.
Common Plants of the Mid-Atlantic Coast by Gene M. Silberhorn lists
Opuntia compressa (probably a variety of O. humifusa) as a common dune
plant. This species has "few or no spines, but its many tiny bristles
(glochids) irritate the skin if handled." He says the fruits are edible
and are used for jam. According to Herbaceous Plants of Maryland by
Brown and Brown, they also grow on the dry, shaly soils of the
ridge-and-valley region just east of the Appalachian plateau.
It appears that prickly pears do not grow in Florida, probably not
anywhere on the Gulf Coast. All of the North American species I've
found described, grow only on dry sands and rocky outcrops.
In The Gourmet Gardener, E. Annie Proulx (who went on to become a
novelist, author of The Shipping News), gives information on growing,
harvesting, and cooking "nopal", which is the fruit of the southwestern
prickly pear. She recommends growing them for their ornamental value,
as well, in a rock garden or in pots of very sandy soil. She says seeds
of a very cold-hardy type (collected in Nebraska) are available from J.
L. Hudson Seeds. That was the only source of seeds she could find, but
you might search native plant nurseries.
I've seen the pads for sale in Asian markets, but have never eaten them
myself. In the Peterson Field Guide to Edible Wild Plants, Lee Allen
Peterson says that the pads can be peeled and prepared like green beans,
and the seeds can be ground to use as flour or a soup thickener. She
suggests removing the bristles with a damp cloth, while Annie Proulx
recommends cutting them off with a sharp knife. (Wearing sturdy gloves,
in either case.)
Brown and Brown describe the fruits as "edible but rather flavorless."
This raises the question of whether fruit quality varies according to
species (or within species), or according to growing conditions, e.g.,
day length, length of growing season.
I think it could be an excellent specialty product for sale to ethnic
and gourmet markets, for people who happen to have the right growing
conditions - which would be unproductive for other uses! I'd love to
try growing it myself and would join an interest group if there is one.