Where in zone 7b are you located?

I've been mulling over your question, and decided you may have to plant more than one type of vine so that you will have flowering in your two different seasons, spring (April thru May) and late summer to fall (August thru October, maybe November, depending on weather. Also, the butterflies will not be on the wing much after October/November, and will not return until possibly late March into April, at least, in a zone 7b garden. There is some leeway in the end of fall season butterflies, when the butterflies move South to warmer areas to overwinter, and the returning spring butterflies, depending on when the butterflies move North to repopulate your temperate zone, weather, etc.

So, the period of time you would need flowering, or larval hosts (vines that certain butterflies will lay their eggs on, and their caterpillars will consume until they reach the stage where they form a chrysalis, is (guesstimating):

August thru October (maybe November)
April thru May, when school ends for the year

If you can give me your location, I can identify what butterflies you may attract in your area. I can also give you some suggestions for strictly nectar producing vines as well.

Also, are you looking for annuals, vines that grow, flower, and produce seed in one gardening year and die, or perennial vines that grow and return each year. Some annual vines may reseed and grow again each year.

One vine I already have in mind is a Passion Vine (Passiflora), such as 'Lavendar Lady', 'Incense', or P. caerulea. Avoid P. incarnata it is pretty invasive. These vines will start flowering in late summer at least, and flower until frost. They are also a larval host plant for the Gulf Fritillary butterfly, depending on where you are located.

Susan

There are no vines I know of that are good nectar plants for butterflies.

Hop vine is one I use that attracts Commas and Question Marks as a host plant.

I also use a Lonicera for hummers and also as a possible host plant for the hummingbird moth.

I have found Pipevine to be invasive so it had to go.

Butterflyman, there are a few good options that have been discussed in this forum before:

http://forums.gardenweb.com/forums/load/butterfly/msg0816441112954.html

Tony

Here is a link that might be useful: Butterfly Vines

You can read folks' opinions on sandvine via the link below.

Here is a link that might be useful: Cynanchum laeve