How to Grow Empress Wu

Empress Wu

Clematis 'Empress Wu'

vine

Empress Wu is a large-flowered clematis vine known for its stunning deep purple, fully double flowers that can reach 6-8 inches in diameter. This deciduous climbing vine produces abundant blooms in early summer and often reblooms in late summer. It's a vigorous grower that can reach 8-10 feet tall and is prized for adding dramatic color to pergolas, trellises, and garden structures.

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Example Empress Wu timeline · Pittsburgh, PA (Zone 6b)

  1. Plant Empress Wu

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest Empress Wu

    Late summer into fall

    Before the first fall frost (≈ Nov 8)

Sample dates for Pittsburgh, PA. Sign up to get exact Empress Wu dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun to partial shade; prefers 6+ hours of direct sunlight for best blooming, with afternoon shade in hot climates
💧
Water: Regular watering during growing season, keeping soil consistently moist but not waterlogged. Reduce watering in winter. Drought-tolerant once established, but flowers better with adequate moisture.
📏
Spacing: 36 inches
📅
Days to maturity: 2-3 years to reach full flowering potential
🌱
Planting depth: Plant with crown 1-2 inches below soil surface to protect against clematis wilt

Soil

Type: Well-draining, fertile loamy soil rich in organic matter
pH: 6.0-7.0
Amendments:
Compost Aged bark Peat moss Lime (if pH is too acidic)

Growing Zones

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Thrives in zones 4-9, with best performance in zones 5-8

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

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Growth Stages

1

Establishment

Spring through first summer

Young vine with emerging shoots and developing root system; sparse foliage at first

Water regularly, mulch heavily, provide sturdy support structure early. Avoid deep digging near roots. Plant crown slightly deeper than container level.

2

Vegetative Growth

Summer of establishment year through following spring

Vigorous vine producing abundant twining stems and compound leaves; establishing main framework

Guide vines onto trellis or support. Fertilize monthly with balanced or high-phosphorus fertilizer. Pinch back growing tips to encourage bushier growth if needed.

3

Bud Formation

Late spring, 3-4 weeks before flowering

Flower buds develop along stems; distinctive double buds become visible before opening

Maintain consistent moisture and avoid physical disturbance. Do not prune heavily during this stage. Continue light fertilizing with lower nitrogen formula.

4

Flowering

June-July, with potential repeat bloom in August-September

Magnificent deep purple, fully double flowers (6-8 inches across) bloom abundantly along the vine; flowers may have greenish stamens in center

Deadhead spent flowers to encourage continued blooming and potential rebloom. Water consistently. Monitor for pests and diseases. Stake any heavy-flowering areas.

5

Post-Bloom & Dormancy

Late summer through fall/winter

Flower production slows; vine enters late-season growth phase; foliage begins to decline in fall

Cut back spent vines after hard frost. Light pruning in late fall or early spring to shape and remove dead wood. No fertilizing in late season.

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

Competing vigorous vines Plants requiring constant root disturbance Plants sensitive to afternoon heat in hot climates Salt-tolerant plantings that may compete for water

Common Pests

  • Plant crown 1-2 inches deep; remove affected stems to healthy tissue; improve air circulation; avoid wounding stems. No chemical control; prevention is key.

  • Increase humidity and water foliage; spray with strong water stream; use insecticidal soap or neem oil if severe

  • Spray with water; use insecticidal soap or horticultural oil; encourage beneficial insects like ladybugs

  • and

    Remove by hand, especially near base; use slug bait or barriers; encourage ground beetles

  • Improve air circulation; remove affected leaves; spray with sulfur or potassium bicarbonate fungicide; avoid wetting foliage

Uses

🏠

Cut Flower Arrangements

Household

The large, showy double flowers are stunning in fresh flower arrangements and floral design. The fully double form creates visual impact that lasts up to 10 days in water. [source]

🏠

Garden Structure Ornament

Household

Perfect for covering pergolas, arbors, trellises, and walls, providing dramatic purple color and visual interest throughout the blooming season. The vine's dense coverage creates privacy and shade while flowering. [source]

🦋

Pollinator Support

Wildlife

Attracts butterflies and other pollinators to the garden, supporting local ecosystems. Even though these are double flowers with reduced stamens, the plant still provides nectar resources. [source]

🎨

Pressed Flower Craft

Craft

The large, flat double flowers can be pressed and dried for craft projects, cards, bookmarks, and decorative items, preserving their beautiful purple color when properly dried. [source]

Harvest Tips

Not a harvested plant. Enjoy flowers by cutting stems for fresh arrangements. Cut flowers last 7-10 days in a vase. Cut stems in early morning when hydrated. Remove lower leaves that would sit in water.

Fun Facts

  • 🌱 Empress Wu is a Group 2 clematis (early large-flowered), named to honor the famous Chinese empress Wu Zetian, and it can produce flowers up to 8 inches wide—among the largest in the clematis world.
  • 🌱 The double flowers are so full that the stamens are largely obscured, giving them a pompom-like appearance; however, the plant can still rebloom on new wood in late summer if managed properly.
  • 🌱 Clematis vines climb using petioles (leaf stalks) that twine around supports, making them excellent for adding vertical garden interest without heavy installation like clematis-specific trellises.

Gardening Terms

New to gardening? Learn about terms used in this guide:

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