I have several different Epimedium plants in my garden. The one in nearly full shade is blooming but those in partial sun/shade and nearly full sun have luxurious foliage but few if any blooms. Is it due to the difference in sunlight or some other factor. My soil tends to be acidic and is sandy enhanced by compost. Any advice would be welcome. Thanks.

Some epimediums are just naturally shy bloomers. But if these are all the same type, it might be because the shady one has more root competition and the "non-blooming" enjoy free reign in the soil?