Not sure what your plant is, but all I know is that planting one tomatillo will not work. They cannot reproduce alone, they need cross pollination with other tomatillo plants, at least one other tomatillo plant. I made that mistake last year, and this year again, when I got one of mine mixed up and planted isolated. The ones that are able to 'mingle' look great with tons of fruit. I have a tomato near by too, seems to have no effect one way or the other...

Evidence of cross-pollination would only show up next year, when you grow new plants from the seeds you collect this year.

Thanks for the responses. I looked more closely at the plant and it looks like another tomato plant sprawled over the tomatillo. Wish I could find the tag for it, because I really like it! :)

Actually, I've planted only one tomatillo plant for years and have had some great harvests. This year's was decent as far as number of crop picked, but they were perfect as far as taste and size, complete with husks. And I'm the only garden on the block.

I think I read somewhere that the purple tomatillos dont need a second plant for pollination.