Clematis macropetala 'Mountaindale'

Clematis of the Month for March 2024

Described by Linda Beutler

C. macropetala 'Mountaindale'

For 18 years, from 1987-2005, the Rogerson Clematis Collection (RCC) thrived in a greenhouse at Gutmann Nursery, 2.5 miles from the sleepy hamlet of Mountaindale, Oregon. If we're honest, comatose might be a better word than sleepy. Tiny "downtown" Mountaindale was a T-intersection where Dairy Creek Road headed north into the Coast Range off Mountaindale Road. It is here that we begin the origin story of Clematis macropetala 'Mountaindale'.

Gutmann Nursery existed as a clematis and groundcover specialty grower before the arrival of the RCC. Bob and Carol Gutmann did some of their own propagation, and they also brought in plants from such local suppliers as there were. One of them, Gary Senner, had two forms of C. macropetala he sold wholesale as finished gallons, described as "the blue one and the pink one". Once Brewster was on hand to write the Gutmann catalog, it was promptly determined that "the pink one" was C. 'Markham's Pink'.

By the time Gary Senner retired in the early 2000s, Brewster and Bob had observed "the blue one" long enough to think it superior enough to be named. Keep in mind it would have been compared with other variants and formae of C. macropetala in the RCC, including wild collections sent to Brewster through Magnus Johnson, including "forma farrer" and a form said to have been collected by Raymond Evison. (Sadly, both died before the Rogerson Clematis Garden was developed.)

Seen up very close, the coloration on the sepal reverse is amazingly vibrant and varied.

"The blue one" also had stiff competition for attention from the blue cultivars in the Collection at that time, such as C. macropetala 'Lagoon' (still in the American trade), C. macropetala 'Blue Jay' (developed by Monrovia Nursery and not heard from in 20 years), and three bred by Magnus Johnson, C. 'Ballerina in Blue', C. 'Floral Feast', and C. 'Sialia'. All three are not available in North America at present.

Two characteristics distinguish C. macropetala 'Mountaindale' from its fellows. First—and most important to Brewster—was the clarity of the blue color, especially when grown in partial shade. In full or afternoon sun, the outer tepals appear more purple, aging to the same gemstone blue as the inner staminode sepals.

C. macropetala 'Mountaindale' blooming right on time, 21 April 2021. Growing in a container next to a violet-purple bench does give this specimen a more purple than true blue appearance.

The second characteristic was the ease of rebloom. Even without deadheading, C. macropetala 'Mountaindale' rushes back into bloom with only the slightest amount of encouragement. If you deadhead or lightly prune as needed after it flowers the first time, and give a taste of fertilizer, you can have April again in August. The long growing season in the Pacific Northwest means three waves of bloom are the norm, from April to October.

Just before and after dawn on 11 April, 2022 the garden received 5cm of heavy wet snow that took four hours to melt. This image was taken two days later. C. macropetala 'Mountaindale' simply responded: "Yes, please."

With a fresh dusting of dry organic rose and flower food, and a drench or two of liquid organic tomato fertilizer, we have no trouble getting C. macropetala 'Mountaindale' back into bloom. This image is from 30 July 2021.

C. macropetala 'Mountaindale' has been an excellent plant for containers. We use a free draining potting soil in frost-proof glazed ceramic containers. The potting soil has pumice and sand added to a bark and coir blend for excellent drainage and long-term structure. In the ground, this cultivar may reach 8 feet or 2.5 meters tall, but it is easy to keep inbounds on a shorter plant support in a pot. Whether in the ground or in a container, we follow our "AN AF" protocol: prune As Needed After Flowering. This means you may prune as hard or as gently as you think fit if you do it immediately after flowering has ceased in the spring.

These 1-liter pots of C. macropetala 'Mountaindale' positively bask in a February snowfall.

Once Brewster started having regular volunteers drive out to help him—taking the Mountaindale exit from the freeway—its popularity started to spread, leading quickly to his registering it in time for the second supplement to the International Clematis Register and Checklist. The description he offered is uncharacteristically brief. I like to think the name choice serves two purposes, with both a nod to the area where the RCC grew for so many years and a description of the color of a shadowy, even misty mountain valley.

Linda Beutler