I certainly agree with what David has just written. But my original post on this topic was written not with flowers per se in mind but with flowering plants. Many butterflies have very specific tastes in food plants. There again, in that sentence, I've done it again. I wrote butterflies (meaning butterfly species) but to be clear I should have written butterfly larvae. Only a month or so ago I watched a monarch circle in on some non-blooming milkweeds. I assumed scent was guiding it, but who knows, maybe the foliage has a very distinctive visual pattern which they see. Jim McKenney Montgomery County, Maryland, USA, USDA zone 7, where the Lachenalia are rapidly putting up new foliage.