Q.Hydrangea seed sowing
I have been told, you should sow hydrangea seeds on the surface of the soil. But I have seen tiny seeds and larger seeds. Are all hydrangea seeds to be sowed on the surface? Also, if germinating seeds with the paper towel method and after noticing the root appearing should I just put on the surface, or should I plant it?
L

Certified GKH Gardening Expert
They do need bright light to germinate properly, so you will want to germinate these on the top of the soil.
I do not recommend using the papertowel method here, as there is a very important set of timings that nature provides for the seed in order to grow properly. Missing them will likely yield a plant that is not sturdy, does not grow fast, or dies completely.
This article will help: https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/growing-hydrangeas-from-seed.htm