Jackmanii was the first of the modern hybrid large-flowered clematis to be grown in gardens and it continues to be very popular today. Many sources list it as hardy to zone 4, but in a more protected location it has been known to be hardy to zone 3. Since it gets so large, a sturdy support or trellis will be needed. It will tolerate being planted close to black walnut trees. Does not do well in heavy clay soils.
THUG ALERT! Even cutting it completely to the ground in early spring didn't stop it from taking over a trellis to either side in addition to its own space. When I put it in, I also didn't realize it was invasive -- and there's just no way to deadhead every bloom. I dug mine up, threw it out, and I'm still pulling seedlings out here and there 3 years later.
As clematises go, Nelly Moser might be considered a classic. It is widely grown and has been so for a number of years. When well grown, it blooms heavily in the spring and reblooms later with fewer blossoms. Unfortunately, the flowers fade quickly, but it is still very attractive. It can be pruned moderately in early spring and lightly after spring bloom.
The description on my plant tag, from Donahue's Clematis, reads:
The blooms are very vibrant and double/semi-double at times.
This clematis is fairly easy to grow in my zone 8a SC garden and thrives in full sun. Its blooms do not fade in intense sunshine.
With age, the outer tepals fall off, creating a pompom. This clematis has no anthers. Can get strange green flowers if planted in too much shade, but does best with some shade to prevent fading.
Venosa Violcea means "violet veins." To encourage new growth, give it a light pruning when the first round of flowers is fading. This should produce another round of flowers. Has excellent resistance to clematis wilt. Very vigorous and free-flowering. You won't be disappointed with this one!
Extremely generous with blooms. First blooms are much larger than later ones. I cut mine back hard last year and it has rebounded and flowered more than ever.
A good Clematis to grow in the north, * 'Comtesse de Bouchard', a vigorous climber, reaches more than 8 feet tall in one year. It flowered from mid-June to late August with 5-inch-diameter mauve-pink flowers. During its peak bloom period, flowers covered 80 to 100 percent of the plant. Bloom repeats in October. Comtesse de Bouchard plants had little winter dieback but, in two of the study years, had some dieback from clematis wilt.
