Jackmanii Clematis
Jackmanii Clematis
The Iconic Velvety Royal-Purple Clematis, Smothered in Bloom
Jackmanii Clematis (Clematis 'Jackmanii') is the most famous clematis of all — a vigorous climber that disappears under sheets of velvety royal-purple flowers from midsummer to fall. Tough, reliable, and beginner-friendly, it's zone 4 hardy and uses the easy Group 3 pruning (just cut it back each spring). Like all clematis, it wants its top in the sun and roots in cool shade. Whether you're covering a fence in Edina, climbing an arbor in Maple Grove, or scrambling up a mailbox in Woodbury — Jackmanii brings unbeatable purple to zone 4b–5a yards.
Jackmanii Clematis Plant Details
| Attribute | Detail |
|---|---|
| Scientific Name | Clematis 'Jackmanii' |
| Plant Type | Deciduous flowering climbing vine |
| Mature Height | 10–14 feet (with support) |
| Mature Spread | 3–4 feet |
| Sun | Full sun to part shade (6+ hours for best bloom); keep the roots cool and shaded |
| Water | Moderate — consistent moisture in well-draining soil |
| USDA Zones | 4–8 (Twin Cities is zone 4b–5a) |
| Soil | Rich, well-draining; amend Minnesota clay-loam with compost |
| Pruning Group | Group 3 (cut back hard in early spring); blooms on new wood |
| Bloom | Velvety royal-purple flowers in profusion, midsummer through fall |
| Winter Hardiness | Reliable to zone 4; mulch the crown the first winter |
Jackmanii Clematis Uses in Minnesota Landscapes
Fences, arbors, and pergolas
Its vigor makes it the go-to for covering a chain-link fence, arbor, or pergola fast in Plymouth. Give it thin supports its leaf stems can twine around.
Scrambling through shrubs
A classic trick: let Jackmanii weave up through a spring-blooming shrub or evergreen to add a second season of purple in Eden Prairie.
Cut flowers and pollinators
The abundant blooms are great for cutting, and bees work them all summer.
Best Time to Plant Jackmanii Clematis in Minnesota
Spring (late April–May) and early fall (late August–September) are both excellent. Avoid summer heat, and never plant after mid-October — frost-heaving kills new roots.
How to Plant Jackmanii Clematis
- Site it so the top gets sun but the roots stay cool and shaded — "head in the sun, feet in the shade."
- Dig 2–3× the root ball width and set the plant 2–3 inches deeper than it grew in the pot to guard against clematis wilt.
- Backfill with native soil plus 20–30% compost; firm gently and water in well.
- Install the support at planting and tie young stems to start them climbing.
- Mulch 2–3 inches over the root zone or shade the base with a low perennial; keep mulch off the stems.
Watering Jackmanii Clematis in Minnesota
First Year Watering Schedule
- Weeks 1–2: Every 2–3 days, deep and slow
- Month 1–2: Every 3–4 days
- Month 3–6: Weekly; keep evenly moist but never waterlogged
- Stop watering 2–3 weeks before ground freeze (typically late October in the Twin Cities).
After Year One
Water deeply during dry spells, especially in summer heat. Deep roots and steady moisture keep it covered in bloom.
How do I prune Jackmanii?
It's the easy Group 3 type — ideal for beginners. In early spring, cut the whole plant back to about 12 inches above the ground. It blooms on new wood, so the hard cut just resets it for a full flush.
It's all leaves at the bottom and bare — what happened?
Without the spring hard cut, Group 3 clematis gets leggy and blooms only at the top. Cutting it back each spring keeps it full from the base.
Will it survive a Minnesota winter?
Yes — hardy to zone 4 and very tough. Mulch the crown the first winter or two.
You May Also Like
- Jackmanii Superba Clematis — a richer, broader-petaled purple selection
- Warsaw Nike Clematis — royal velvety purple, Group 3
- Cardinal Wyszynski Clematis — glowing crimson companion