A clematis doesn’t have to be big to be bold. Picardy™ (‘Evipo024’) epitomizes this rule; its compact habit certainly doesn’t restrain the boldness of the vivid, violet-red flowers. This is no shrinking violet! Picardy™ is free flowering and often reblooms into late summer. Topping out at 5 feet tall, its petite size is suitable for containers and for small patios where larger clematis would be overwhelming.

If someone were to ask me for a list of my favorite plants right now, ‘Princess Diana’ clematis would definitely top that list. Its tuliplike flowers are not only beautiful but also strikingly different in form from most large-flowered hybrids. The luminous tepals flare outward like a trumpet as they mature, revealing the creamy yellow stamens. ‘Princess Diana’ has a wispy habit when first planted but is a strong grower that gets more robust with age. It pairs surprisingly nicely with the gently nodding, lavender-blue flowers of ‘Prince Charles’ clematis.

To look upon Blue Angel™ (‘Blekitny Aniol’) in full, glorious bloom is a heavenly sight indeed. A pale center and ruffled edges enhance the etherealness of its charming blue blossoms. Hundreds of flowers blanket its robust stems each summer, making it one of the most prolific bloomers I’ve ever seen. Blue Angel™, however, is not for the faint of heart; its Jack-and-the-Beanstalk growth rate can be daunting to a timid gardener. An eastern exposure is ideal for growing Blue Angel™ and other light-colored clematis because strong sunlight will fade pastel flowers. Reserve southern and western positions for clematis in deeper shades of blue, red, and purple.

Pink Champagne™ (‘’Kakio’ is one of the earliest large-flowered clematis to bloom. As the name implies, this variety boasts bubbly, bright pink tepals with pale centers and bright yellow stamens. Pink Champagne™ is a strong climber with a fairly narrow expanse, meaning it works well in tight spaces. I grow this variety alongside my garden gate in a cramped space that is less than a foot wide. The stems shoot straight up, making a beautiful pink exclamation point.

‘Viola’ is, in a word, sumptuous. The velvety, dark purple flowers are exceptional in their profusion and richness. This is a vigorous vine, reaching 10 feet tall, but climbs reasonably well without too much assistance (unlike some other large clematis varieties). Although we grew ‘Viola’ on a chain-link fence—ho hum—I always imagined its richly colored flowers more splendidly displayed against a silvery blue conifer or perhaps intertwined with a pearly white–flowered ‘Huldine’ or a rosy ‘Margot Koster’ clematis.

‘Wada’s Primrose’ embodies the very definition of flower power: A bumper crop of delicate primrose yellow flowers clothe the stems from top to bottom, sometimes beginning as early as mid-spring. I find the harmonious combination of soft yellow tepals and yellow stamens quite soothing. ‘Wada’s Primrose’ has a refined habit, growing straight upward rather than taking a more circuitous path to the top of the fence. At 8 feet tall, it may seem incongruous to recommend ‘Wada’s Primrose’ for small spaces, but its verticality is an unfailing trait.

I first saw ‘Madame Julia Correvon’ grown to perfection in England and knew instantly that I wanted it for the CBG trial and my garden at home. The nodding, claret red tepals twist backward, giving the flowers a gappy appearance and thrusting their golden eye of stamens in your face. The sweetly scented blossoms are produced in great profusion for well over a month, beginning in late spring, and then reappear sporadically until the first frost. Because ‘Madame Julia Correvon’ blooms a bit early for a C. viticella–type clematis, its first flowers mingle beautifully with the waning blossoms of the popular ‘New Dawn’ rose (Rosa ‘New Dawn’, Zones 5–9).

How to Prune Clematis

The thing that causes the most confusion and angst for gardeners when it comes to clematis is pruning. Cut them back incorrectly and you won’t get any flowers; don’t cut them back at all and the plants may never reach their potential. In the 1960s, growers lumped clematis into three groups to simplify pruning. Rather than being scientific or taxonomic, these groups are based on the flowering habits of clematis—whether they bloom on old or new stems. This article deals only with the clematis that fall into either pruning group 2 or group 3. Here’s how to trim those types:

Group 2

VINES Form flower buds in the previous growing season and include large-flowered and double-flowered cultivars that bloom in spring and in early to midsummer.

Prune minimally to remove dead or errant stems in late winter to early spring. Waiting until the leaf buds begin to swell makes it easier to see what’s alive and what’s not, which helps preserve as many flowers as possible.

Some varieties, such as ‘Marie Boisselot’ and ‘Pink Fantasy’, can produce flowers on new stems, too, so pruning these varieties back to a foot in late winter encourages a later bloom season.

RATING KEY

★★★★ Excellent

★★★ Good

★★ Fair

★ Poor

(v) Clematis viticella group

^ Sporadic flowering noted after the initial bloom period

How We Did the Trial

New Kids on the Block

The following clematis have been in the trial for only four years but, so far, are showing signs of being exceptional plants.

When I first saw the crimson flowers of Rüütel™ (‘Kiviruut’) in 2009, I was like a wide-eyed kid experiencing a Christmas miracle. It’s truly a luscious color. The 7-inch-wide flowers feature deeply grooved tepals with ruffled edges and similarly colored stamens, which give it a monochromatic look that I love. Rüütel™ blooms from late spring to midsummer on stems that only reach 6 feet tall, making it perfect for small patios where the luxuriant blossoms can be viewed up close. Rüütel™ is an easy-care (pruning group 3) clematis.

Piilu™ (‘Kivso’), which translates as “little duckling,” has pretty bicolored flowers with pale purplish pink margins and deep pink central bars. I’m particularly impressed by its prodigious flower production—it’s one of the most floriferous clematis I’ve ever grown. The open-faced flowers, 3 to 4 inches wide, are produced from early to late summer and are nicely distributed over the entire plant. The early flowers are supposedly semi-double, but I’ve only seen single flowers on our plants. This is a strong climber, reaching 6 feet tall with a narrow but full habit. For pruning purposes, Piilu™ blooms on old wood, so it can be lumped into group 1 or 2. This also means that it will flower earlier if there is no winter injury to the stems.

Double-flowered plants aren’t always my cup of tea; there’s something a bit fussy looking about them. But I make an exception for ‘Teshio’. Its spiky, double, lavender-blue flowers, stretching to 5 inches wide, are reminiscent of the venerable ‘Belle of Woking’ clematis, albeit darker. It’s fun to watch the spidery tepals unfurl—a bit haphazardly, at first, but eventually morphing into a pretty, well-structured blossom. ‘Teshio’ is a fairly strong bloomer from late spring to early summer, sometimes reblooming later in summer. It maintains a compact, bushy habit, reaching 7 feet tall, and is perfect for containers or patio plantings. Clematis is a great cut flower, and the spidery blossoms of ‘Teshio’ create quite a buzz in a floral arrangement.

There have been many wonderful clematis introductions over the years, stretching as far back as the 1800s. So Starburst™ (‘Roblom’), which was introduced in 2008, is a real newbie compared to ‘Jackmanii’, a garden standard that was introduced in 1858. Starburst™ features exuberant, 7-inch-wide magenta flowers with a big boss of yellow stamens from mid- to late spring. The creamy centers of each tepal display a starburst pattern within the darker flower. This is an impressive bloomer and a strong climber, reaching up to 8 feet tall.