All plants except ericaceous (acid-loving) ones will thrive on the minerals that make up human ashes (which is mostly calcium phosphate).

So basically avoid heathers and rhododendrons.

The 'ashes' will primarily be wood ash... not human ash, remember the coffin is cremated along with the body.

Hi Mg, actually when a body is cremated, it's only burned until there are only bones left, all the wood ash and body fats are raked out of the cremator first, then the bones are taken out and put into a cremulator, which is like a big tumble dryer, with large round stones, which smash the bones to powder, so you do actually get human ash, without the wood etc, I used to be in charge of a cemetery/ crematorium, as well as a park, Derek.

Okay Derek, you obviously know more than me :)

This is probably the most unusual question I have ever encountered on GOY...my answer based upon what I have seen in my lifetime and travels is that wildflowers do wonderfully in human ashes if you wish to grow plants which are not potted.

I have dealt with this before. The thing to remember is that pure ashes--human or otherwise--are extremely alkaline, almost to the point of being caustic. Trying to grow flowers in pure ashes will almost certainly burn the roots off. From what I know, the ashes should not be more than 2% of the growing medium, ideally.