I was forced to move several May Nights, as well as many other perennials last fall. It was actually quite a bit later in the fall than I would have liked, but I kept them well watered until freezing. Most of the plants survived surprisingly well and I believe every one of the Salvias did fine. I don't specifically know about the soil, but mine are in full sun. I do water during extended dry periods though. Hope this helps.

Salvias are very hardy plants. Plants may be easily divided in early spring or fall but I've moved them in the summer also. They grow like a weed in my garden. Just give them a good drink for the first few days.

There is a general 'rule of thumb' with transplanting or dividing perennials - Spring bloomers should be moved in the fall, Fall bloomers in the spring. But this is not a hard and fast rule, as I have moved Peonies in the Spring! They didn't like it and sulked for the entire season, but they were fine in the long run. The best weather for transplanting are the cool and drizzly days kinda like today - you don't have to worry about the roots drying out at all, and the rain helps the plant settle in. It is a very messy activity when it's wet, I guess it's like playing in the mud when you were a kid! This Spring so far, I have moved 2 large shrubs, some smaller ones, a whole mass of Hostas, and a bunch of bulbs. Most of these were near the house, so the soil was "warmed up" and very workable. I haven't plunged headlong into transplanting anything out in the garden beds yet, but very soon. Sounds like this week's going to warm up, so it should be no problem to get going on this. As for seeds, cool season plants can be sown now - Poppies, Fennel, cool season veggies, etc. I would wait until after the last frost to direct sow warm season seeds.

Susan: Sorry to hear of your problem. You can use a product which is organic (not a chemical pesticide). It is sold under several names locally. See if you can find this Thuricide or BT (Bacillus Thuringiensis var kurstaki) it only targets what it is sprayed on will not hurt good insects like lady bugs, praying mantis, etc.. washes off and has no long term activity.So as not to harm your butterfly larva. As to were your to put your B&B plant is leave it there or move it but the moth larva will still find it.Eliminate the moth larva and they should not come back. I have not had this problem with my B&B but onther problems. I almost forgot it does not act like a poision (because it is not one) the larva will still be there for a short time but they will stop eating and then die.