It's actually entirely the other way round. Seed grown will be variable. If anyone is selling seed grown hellebores and saying they will definitely be a specific colour they are conning you. Unless they have already flowered and the seller has verified the appearance. The only way to get plants identical to the parents is by division or tissue culture. Plants cannot 'contaminate' each other and they do not change colour in the ground. But if they cross pollinate their offspring will be genetically different from the parents. Just like people. A blonde hugging a brunette will not change each other's hair colour. But if they have sex the kid could have either colour or something in between.

If you have several different colours in your garden those plants will not change. However, their offspring could be different. Over time the offspring tend to all end up dull purple.

Great explanation. Thanks.

Agree totally with

floral_uk z.8/9 SW UK

Hellebores are most promiscuous and you will be an expert with a headache if you want to name them. Two hellebore flowers might look the same and yet one has pointed petals whilst the others with round ones. One have more freckles, more veins, more spots or bigger patches.

Hellebore seeds can throw up a lot of exciting differences. If they are cheap, do buy them. You could easily end up with very different ones. Having said that, seed quality tends to deteriorate, so the markings might not be as emphatic. Hard one to call. One thing good is that fresh hellebore seeds germinate very well.