In my acid soil, I use ashes for plants that like pH a bit closer to neutral like veggies or lilacs. Ashes are alkaline and often get used like lime here. What is your soil pH like in MO? If it's already in the neutral to alkaline range, I'd not add ashes to the garden beds.

Thanks for the feedback. I had a vague feeling this wasn't a good idea and you have confirmed it. I will dispose of the ashes elsewhere.

If you have a compost pile, adding the leaf ashes to the compost will add minerals.

Ashes are good for peonies.

mintcar123, what one should add depends on the growing conditions already in the garden. Peonies like pH in the neutral to slightly acid range. Ashes are alkaline, and if one's soil is acid adding them may be a a good thing, but if one's soil is already alkaline (pH higher than 7) adding ashes could harm the peonies, just like it could harm the Hydrangeas. So your statement isn't accurate in everyone's garden, though it may be helpful in yours.