I’ve never decorated my harp (yet), but if I did I would make sure whatever I used wouldn’t scratch the finish. That being said, here are some warnings: I would be careful with bows-they are usually tied with wire. Silk flowers might be OK, as long as there are no bare wires showing(I am a florist by trade so I know a little bit in this area). Fake pine also has a lot of wire running through it, so be careful of that. Real pine? Sap might stick. Fresh flowers are nice, but they don’t last without a source of water, and you don’t want that on your harp.
Sorry to be somewhat of a killjoy here, but I really think if you are going to decorate your harp for the holidays I would stick to a silk flower garland if anything. Even putting lights on your harp may not be a good idea- the heat source from those little bulbs aren’t good for the wood either. Maybe a ribbon garland? Just tie it up at the top of the pillar and wind it down, like a candystripe? I will try it and let you know, maybe if I can figure out how to download a pic on this site I put it in my next post.