thats what i do. i use the sealer spray for my ceramics, if you dont seal it . it will eventualy wear off.
i dont mind the plant markers. the plants hide them when they fill out, but i do tend to loose them alot, rocks has a more natural look, ive got them mixed up wile weeding, ill pull out a nasty weed
and the rock gose flyin!
i have no luck nomatter what i use, its best i wright down what i plant and were :}