This plant struggled on for years on my balcony, I tried full shade, part shade, the lot. When I moved house at Christmas pots were placed randomly in the garden. Houttuynia cordata was put in afternoon sun. The plant has not been moved since and has not been repotted yet, From the tiniest little shoot that survived the balcony experience and winter in the new place, new life has sprung forth and I just noticed a first flower this evening (low light, hence he poor quality photo). I bought it originally as I read it was tolerant of full shade but it seems to enjoy full sun even more.