I’d take it as an experiment if the price were reasonable, with no great expectations. I don’t know how long it takes for dahlias to go seed to flower, but it’s going to be a few years to see the results on the peony.

The pics, as I see them on my screen, the dahlia looks close to a true blue; the peony is lavender, as I would expect. If there’s a black bleeding heart, it is likely deeeeeeep maroon.