How to Grow Clematis 'Henryi'

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Clematis 'Henryi'

Clematis × jackmanii 'Henryi'

vine

Clematis 'Henryi' is a large-flowered clematis cultivar renowned for its stunning pure white, star-shaped blooms with prominent dark stamens. This vigorous deciduous vine produces flowers 6-8 inches in diameter and blooms prolifically from midsummer through early fall. It is an excellent choice for trellises, arbors, and wall-mounted structures in garden landscapes.

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Example Clematis 'Henryi' timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Clematis 'Henryi'

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Clematis 'Henryi'

    Late summer into fall

    Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Clematis 'Henryi' dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun to partial shade; requires at least 6 hours of direct sunlight daily for best blooming, but prefers cool roots (shade at soil level)
💧
Water: Moderate and consistent moisture; water deeply 2-3 times per week during growing season. Keep soil evenly moist but not waterlogged. Drought-stressed plants produce fewer flowers. Mulch heavily to keep roots cool and retain moisture.
📏
Spacing: 36 inches
📅
Days to maturity: Not applicable (perennial vine); flowers appear in second year after planting
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Planting depth: Plant with top of root ball 2-3 inches below soil surface to protect from clematis wilt

Soil

Type: Well-draining loamy soil with organic matter
pH: 6.0-7.0
Amendments:
Compost Peat moss or coco coir Perlite for drainage Balanced slow-release fertilizer

Growing Zones

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Thrives in zones 4-9; cold hardy in northern regions with winter protection

4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a

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Growth Stages

1

Establishment

3-6 months after planting

Young vine with limited growth; small leaves emerge and vine begins climbing support structure

Keep consistently moist, provide sturdy trellis, apply balanced fertilizer monthly, avoid transplanting; mulch heavily around base

2

Vegetative Growth

Spring through early summer (first year or second year for newly planted vines)

Vigorous foliage development; vine rapidly extends along support with healthy green leaves, no flowers yet

Train stems to cover support structure, prune lightly to encourage branching, maintain consistent moisture and cool roots, feed monthly

3

Flowering

June/July through September/October (3-4 months)

Large white star-shaped flowers with dark stamens appear along stems; multiple blooms open sequentially over several weeks

Deadhead spent flowers to encourage continuous blooming, maintain consistent water during blooming, reduce nitrogen fertilizer (use bloom-promoting formula), stake and tie sprawling stems

4

Dormancy

November through March

Vine dies back to ground level or base in late fall; foliage browns and drops; plant becomes bare for winter

Cut back dead stems to 12 inches above ground in late fall or early spring, apply winter mulch in cold zones (3-4 inches), reduce watering in winter

5

Pruning & Renewal

March through April

Spring emergence with new shoots from base and lower stems; fresh growth indicates vine readiness for another season

Remove any winter-damaged stems, thin crowded growth, apply balanced fertilizer as new growth appears, gradually increase watering

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

Black walnut (allelopathic) Aggressive vines (clematis species) Densely planted shrubs that compete for water

Common Pests

  • Plant deep to protect stems; remove affected stems immediately and destroy; ensure excellent air circulation; avoid wounding stems; apply fungicide if severe; choose resistant cultivars

  • Improve air circulation around vine; water at soil level to avoid wetting foliage; remove heavily infected leaves; apply sulfur or neem oil spray; avoid high nitrogen fertilizer

  • Spray with strong water stream to dislodge; increase humidity; apply insecticidal soap or neem oil; monitor undersides of leaves

  • Remove nearby debris and mulch where they hide; trap in rolled newspaper or aluminum foil; use diatomaceous earth; pick off by hand

  • and

    Remove hiding spots (dense mulch directly against stems); hand-pick in early morning; copper tape or barriers around base; beer traps; nematodes or iron phosphate bait

Uses

🍳

Not edible

Culinary

Clematis 'Henryi' is not suitable for consumption. All parts of the plant contain potential irritants and are toxic if ingested. [source]

🏠

Cut flowers and floral arrangements

Household

The large, pristine white flowers are highly prized for fresh flower arrangements and have excellent vase life lasting 5-7 days. They create stunning focal points in wedding bouquets and formal displays. [source]

🦋

Pollinator and wildlife habitat

Wildlife

The prominent dark stamens attract bees, butterflies, and other pollinators throughout the blooming season. Seed heads provide food and shelter for birds in fall and winter. [source]

🎨

Ornamental vine training and living structures

Craft

Clematis 'Henryi' is ideal for training on arbors, pergolas, trellises, and walls to create stunning living architectural features. Its vigorous growth can cover large structures quickly. [source]

🏠

Ornamental seed heads

Household

In late summer and fall, the plant produces feathery, silvery-white seed heads (achenes) that are highly ornamental and persist into winter, providing structure and visual interest even after flowers fade. [source]

Harvest Tips

Not a harvested plant. Deadhead spent flowers to encourage continuous blooming throughout the season. Cut flowers are excellent for arrangements; cut in early morning when stems are turgid. Allow some flowers to remain late in season to develop attractive feathery seed heads for ornamental interest.

Fun Facts

  • 🌱 Clematis 'Henryi' was first introduced in 1858 and remains one of the most popular large-flowered clematis cultivars worldwide despite being over 165 years old.
  • 🌱 The cultivar name 'Henryi' honors Henry Honywood (sometimes spelled Honeywood), a Victorian gardener and plant breeder, though records of the exact namesake are contested by horticultural historians.
  • 🌱 The dark stamens in the center of Clematis 'Henryi' flowers contain the plant's reproductive organs and are highly attractive to insects; there can be 200+ stamens per flower, creating the distinctive dark star center.

Gardening Terms

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