I already have Arctostaphylos uva-ursi growing on my property. I would like to plant also Gaultheria procumbens. I know the plants are in the same family, but are different species so they should not cross pollinate. Still, they look so much alike that it makes me wonder if cross pollination is really impossible?
No, not likely. They are not quite that closely related. Arctostaphylos is in the Arbutoideae branch of Ericaceae and Gaultheria is in the Vaccinioideae. http://www.mobot.org/MOBOT/research/APweb/ (Search for Arctostaphylos and follow link to ericales.)
