I am using all different labels at the moment. I like the Alitags as invisible markers as they last so long (unless trod on over and over). I write on them with the special pencil that they sell and it is very permanent. I have also bought some black Jumbo markers to try with a silver paint pen.
On bigger clumps of snowdrops I am using metal tags with a nameplate that I imported from the USA. It really did not work out too expensive and I needed them for my daylilies. For the snowdrops I write on them with a black paint pen and it makes life very easy when taking photographs. I have the link somewhere if anyone is interested. Pity we do not have such labels available in England. I also use them on my Hellebores and Hostas.
Jennie