Good question. I'm not really sure since I haven't tried it. I haven't used embroidery floss since I was a teenager, so it's been awhile, but I think my main concern is the colorfastness of particular colors. Between the sun and the rain, you may run into quite a bit of fading, but I would say its worth a try. Start off with colors that are very different from each other (such as turquoise, dark purple, red, yellow, etc...). They aren't likely to fade within just a few days, so if you *do* start to notice fading, you should have time to correct the situation and come up with a different solution. The trouble is remembering to switch out ALL of your 'tags' if you change the pollinator that tag represents.
