Clematis jackmanii [ Klem’-a-tis, jak-MAN-ee-eye] is a cultivar of the Clematis genus and part of the buttercup family Ranunculaceae.
The vine was first introduced in 1862 as a modern large-flowered hybrid clematis plant to grow in the garden.
This clematis vine (Clematis x jackmanii) is known for its deep purple flowers, which put on a beautiful display in the summer.
This hybrid clematis vine, has the parents of C. lanuginose and C. viticella.
Common names for the Clematis include:
- Jackmannii clematis
- Jackman clematis
These names come from the breeder’s name, George Jackman.
Clematis Jackmanii Care
Size & Growth
When grown in the right hardiness zones and all growing conditions are met, the plant grows at a pretty fast growth rate.
It can grow upwards of 7’ feet when growing on a trellis or spread as ground cover with a 3’ – 6’ foot spread.
Jackmanii Flowers, Bloom Time and Fragrance
This bloomer produces violet to deep-purple flowers. The bloom time for Clematis-jackmanii is typically during the late summer in July.
Most of these plants have large flat or bell-shaped flowers.
The flowers are typically 4-petaled but some varieties will have 5 or 6.
When held open, each flower measures somewhere around 3” – 4” inches across.
The blooms start at a dark purple color but fade to a vivid violet over time, which contrasts beautifully with the creamy-greenish anthers in the middle.
Based on the pruning group this flowering vine belongs to, the flowers grow differently on each variety.
In some clematis vines, the flowers grow on old wood only, while some bloom on only new wood.
Then there are some clematis varieties with flowering on both old and new growth.
GROWER TIP: All clematis bloom better where the vines reach full sun, but they like shade at their root bases.
Light & Temperature
The plants in this cultivar are hardy to USDA Zones 4 through 8.
Clematis vines love to bask in full sun but also thrive in partial sun.
When the afternoon sun gets too hot or humid, part shade is beneficial.
This is why the ideal regions for growing clematis incudes the Midwest, Southeast, Northeast, and Pacific North West.
Water and Feeding
Jackmanii plants prefer moist soil. The root system thrives with deep watering, especially when the weather is too hot.
In the rainy season, increase the gap between watering to prevent root rot.
In addition to watering, thick root mulch will be helpful in keeping the soil moist.
Feed clematis during the growing season which lasts from April until late August (early fall) with a general-purpose fertilizer in 10-10-10 NPK ratio.
Soil & Transplanting
Clematis plants prefer neutral or slightly alkaline type soils.
It should be able to retain a medium level of moisture with good drainage and high fertility.
They do not tolerate poor, clay or sand-like soils.
The roots of most Clematis species don’t really do well once they have been uprooted.
Transplanting is best avoided and only should be done if the vine isn’t growing well in its current location.
If you are transplanting, be very careful and very patient. Give the vine and roots some extra love for the next year so it can recover from the stress of being moved.
Grooming and Maintenance
What type of clematis is the Jackmanii vine? Jackman falls into Group 2 producing flowers on old wood and new wood.
Prune plants back about at least one-third of old growth in late winter or early spring before new growth emerges.
You may also like the Evergreen Clematis Armandii
How to Propagate Jackman Clematis
The plant is propagated most successfully with cuttings.
Softwood and semi-hardwood cuttings in early spring, early summer, late summer or fall.
If you want to start the plant from seeds, sow them in vented containers in a cold frame.
Once the last frost has passed and the seedlings are big enough to be moved, move the plants out.
Jackman Clematis Pest or Diseases
There are no serious pest and disease problems plaguing the Clematis cultivar besides clematis wilt.
This wilt is fatal to the plant and requires immediate action to remedy.
All parts of the Clematis jackmanii cultivar are poisonous to animals including cats, dogs, and horses.
It can irritate the skin and eyes upon direct contact.
Be careful when planting jackman Clematis with kids and animals around.
Clematis Jackmanii Uses
Train this plant type to climb a wall, trellises, fence, arbor, lamppost, and arbors along with other small structures.
They combine well with other climbers such as climbing roses.
The plants work great for small gardens.
The Clematis vine is often grown at ground level to form a ground cover. They also looked great sprawled across other shrubs and stumps.