About Virgin's Bower
Vigorous native vine with festoons of small white flowers in summer. Suitable as a cut flower, with interesting seed heads. Good to ramble over slopes, it can spread aggressively by roots and self-seeding. Takes part shade. Can be pruned any time; treat as Group 3 for a bushier plant, or don't prune and allow it to ramble. Seed from Grant County, Wis.
About Clematis
Showy flowers in a range of colors and shapes. Best in full sun (unless noted otherwise), with roots protected from the hottest midday rays. Climbs by twining leaves that must grab something less than a half-inch in diameter. All clematis are toxic to people and pets. Deer- and rabbit-resistant. Great scrambling through shrubs or other supports, or even as a ground cover. Here's a note on pruning groups.