I have two 3-year old Heucheras - I THINK they're Melting Fire - that don't seem to be getting any bigger and haven't yet bloomed. (I know the flowers are fairly insignificant on Heucheras, but I want the seeds.)

I keep them in a sunny spot of the garden. I don't water my flower beds very often. Living in New England, it isn't usually a problem. The leaves look healthy enough. But in three years, they're each still only about 6-8 inches tall and only about a 10-inch spread.

I can move them this spring to a shadier, wetter area if that's what they need.

Any ideas?