I do not know when I first met this plant as I feel like I have known it all my life. Where I grew up it is on the coldest edge of its temperature tolerance. I know I have seen it many places here in it’s many forms and colors. I think i like the very first form with its strong color and single flowers. Jackman Clematis (Clematis x jackmanii) is one of the true glories of the summer garden whether it is popping through a tree or doing the service of rambling over the ugly stump in the garden. We welcome all that you do for us!
Jackman Clematis are named for the famous family of nurserymen who developed them. The first member we meet is William(1763-1840) who started the nursery on 50 acres of land in St. Johns Woking, Surrey in England. He had sons George(jr.) and Henry who later took over the nursery in 1830 and this where the real story begins. George jr. (1801-1869) was the real nurseryman while his brother was ran the business. The business was renamed Jackman and Sons Nursery after George. The nursery grew and was prosperous, later George’s eldest son also named George (1837-1887)came to work in the business. The two Georges’ decided to start a breeding program with Clematis to create new forms in 1857. They crossed Clematis lanuginosa with viticella and within the first batch of seedlings was the famous Clematis x jackmanii with its dark purple color and broader petals.
As soon as the first Jackman Clematis started to be sold to the public it was enormous success, everyone wanted one of these beautiful plants. It set a new standard for this species of plants. Soon there were other members of the family to buy and in a broad color range , running from the original deep purple through red, pink, white, shades of lavender and mauve. Several double forms were also named. In 1872 the book ‘The Clematis as a Garden Flower’ was released by George Jackman in collaboration with Thomas Moore. A second edition which was enlarged and updated was issued in 1877.
The Jackman family carried on in the nursery business for several generations until the business was sold in 1967. The Jackman name will always be associated with the best that Clematis can be. Jackman Clematis all are strong growers and often bloom for several months. One of their best attributes is when they bloom later from June into August and often they will have a repeat with the flowers having fewer petals in September.
Clematis are said to be tricky to grow, but having seen them in all kind of places from near-desert conditions to the rain forest here I know they are very adaptable. They like other members of the Ranunculus(Ranunculaceae) family do not like to have their roots disturbed. They can sulk and be slow to return to their glory.
Selection of the right site for your Jackman Clematis is most important. Most members of the group grow up to 3m(10ft) high and a similar width while producing a multitude of vining stems if they are happy. All Clematis like to have their roots in the shade and their stems in the sun for producing the most luxuriant leaves and flowers. In extreme southern sites or excessively stronger sun an eastern exposure is the best. Here in the Pacific Northwest they do nicely in full sun. They like light loamy well-drained soil best. drainage is important to avoid sudden Clematis death which is like a fungus. Give them plenty of moisture during their growing season
Jackman Clematis can be used in a variety of ways. They are impressive growing over fences and on trellises. If you have something to hide let a colorful Clematis help out. Often they are seen in trees which bloom earlier in the year or paired with climbing Roses. We should be more adventurous with our planting and have a sense of fun, the Jackman’s took a chance and changed the garden world in ways that will last forever.
Although Clematis x jackmanii are rated as tolerating -2oc(-4) or zones 4 through 9 I think they can be pushed to cooler places as I have seen healthy ones in zone 3 or -35c(-30 to-40f). They would need extra mulch and care not to go through the freeze/thaw/ freeze which damages so many plants.
On the Jackmanii trail:
A very good write up on Jackman Clematis: http://www.floridata.com/ref/c/clem_xja.cfm
about the Jackman Family: http://www.clematis.hull.ac.uk/new-clemnamedetail.cfm?dbkey=15