It's a much-loved climbing plant that is suitable for gardens of all sizes. They’re perennials, blooming in the spring and summer and dying back in the fall and winter, and can grow up to 20 feet (6.1 m) tall with lifespans of over 80 years. Pests and Other Problems. Pruning Group 3. Expert Raymond Evison recommends the best clematis to grow in the garden. Clematis are naturally robust and easy to grow – once you’ve sorted out the pruning mystique! Pruning Group 3. Among the most popular and easy to grow, Clematis 'Comtesse de Bouchaud' is a lovely deciduous vine which produces masses of large, up to 6 in. For Group 3 cultivar selections, make sure to check out our guide: 19 of the Best Summer Flowering Clematis for Your Garden. Clematis expert Raymond Evison lists his all-time favourite clematis… A vigorous grower, ‘Chatsworth’ is best suited to growing up a sturdy obelisk in a large herbaceous border, or being trained to grow through a tree or shrub. Early autumn is the perfect time to plant clematis. wide (15 cm), shell pink flowers with a touch of lavender, contrasting with the creamy-yellow stamens. Lilac clematis ‘Chatsworth’ But … The more grabbing opportunities you offer the better, so even if you have a nice trellis , consider adding some twine "helper" lines, or covering your trellis with a grid of trellis netting . The easiest things for a clematis to grab onto are twine, fishing line, wire, thin branches, wooden dowels, or steel rods. Clematis are vines that come in a stunning variety of colors and bloom ranges.