From The Buffalo Seed Company:
 
TOMATILLO (Physalis philadelphica) (80 days) — We are not sure where these came from, but they are your standard tomatillos that are better because the seeds were produced in the Midwest. This plant is amazing to watch grow and finishes with a brilliant purple color when mature. Great for making salsa morado, which is a color variation of salsa verde.
 
For best results, tomatillos need to be planted in pairs.  For that reason we are selling these as 2-packs.  Yields will be significantly greater when planted in pairs.