Clematis Care: Growing the Queen of Climbers
Clematis vines, often called the "Queen of Climbers," reward gardeners with a profusion of stunning flowers in nearly every shape and color imaginable. While seemingly intimidating, growing clematis successfully boils down to understanding their basic needs: sunny tops, cool roots, consistent moisture, and, crucially, proper pruning based on their type.
Understanding Clematis Pruning Groups
This is the most important concept for clematis care! Pruning incorrectly can remove flower buds. Clematis are divided into three groups based on when they bloom and on what wood (old or new stems) they produce flowers.
Group 1: Early-Flowering
- Blooms earliest (April-May) on last year's stems (old wood).
- Includes C. montana, C. alpina, C. macropetala.
- Pruning: Prune only if needed for shaping or size control, immediately after flowering finishes in late spring/early summer. Avoid hard pruning.
Group 2: Large-Flowered Hybrids (Repeat Bloomers)
- Produce an early flush of blooms (May-June) on old wood, and often a second, smaller flush later in summer on new wood.
- Includes many popular large-flowered varieties like 'Nelly Moser', 'The President', 'Henryi'.
- Pruning: Lightly prune in late winter/early spring (Feb-March). Remove dead/weak stems and cut remaining stems back to the topmost pair of strong, healthy buds.
Group 3: Late-Flowering
- Bloom later (July-September) on this year's growth (new wood).
- Includes C. viticella, C. terniflora (Sweet Autumn), C. jackmanii, C. texensis.
- Pruning: Prune hard in late winter/early spring (Feb-March). Cut all stems back to about 12 inches from the ground, just above a pair of healthy buds. This encourages vigorous new growth that will carry the season's flowers.
Planting Clematis
Getting the planting right sets your clematis up for long-term success.
When to Plant
- Spring or Fall: Avoid planting during the heat of summer.
Ideal Growing Conditions
- Light: "Sunny heads, shady feet." The top growth needs at least 6 hours of sun daily for best flowering. However, the roots need to be kept cool and shaded.
- Soil: Fertile, moist, but well-draining soil. Neutral to slightly alkaline pH is preferred.
- Support: Clematis need something to climb on! Provide a trellis, arbor, fence, netting, or even allow them to scramble through sturdy shrubs or small trees. Ensure the support is suitable for the mature size of the variety.
To keep roots cool, plant shallow-rooted perennials or groundcovers around the base, or place flat stones or mulch over the root zone (keeping mulch slightly away from the stems).
Planting Technique
Select a spot with adequate sun for the vine and shade for the base. Ensure good air circulation.
Dig a hole about 18 inches wide and deep. Amend the soil generously with compost or well-rotted manure.
Key Step: Position the plant so the crown (where stems emerge from the root ball) is 3-5 inches below the final soil level. This encourages development of multiple stems from below ground, making the plant more resilient to clematis wilt or stem damage.
Gently backfill the hole with the amended soil, angling the plant slightly towards its support. Water thoroughly.
Apply a 2-3 inch layer of organic mulch around the base (but not touching the stems) to conserve moisture and keep roots cool. Gently tie the existing stems to the support structure.
Watering Clematis
- Clematis prefer consistently moist soil, especially during the growing season and flowering. They do not like to dry out completely.
- Water deeply 1-2 times per week, especially during dry spells. Increase frequency for newly planted vines.
- Ensure good drainage; they don't tolerate waterlogged soil.
Fertilizing Clematis
Clematis are relatively heavy feeders during the growing season.
- Apply a balanced, slow-release fertilizer (like rose or tomato fertilizer) in early spring as growth begins.
- Follow up with applications every 4-6 weeks through the growing season, stopping in late summer. Liquid fertilizers like compost tea can also be used.
- Avoid high-nitrogen fertilizers late in the season.
Training Clematis
- Gently tie new shoots to the support structure as they grow, spreading them out horizontally to encourage branching and more even flowering.
- Clematis climb by wrapping their leaf petioles around supports; they need something relatively thin (less than 1/2 inch diameter) to grasp initially. String, netting, or thin wires work well.
Troubleshooting Common Problems
Clematis Wilt
Symptoms and Management
This fungal disease causes sudden wilting and blackening of stems and leaves, often starting mid-stem. It can kill stems back to the ground.
- Action: Immediately cut affected stems back to healthy tissue below the soil line. Dispose of cuttings (do not compost).
- Prevention: Planting deeply encourages new shoots from below ground if wilt strikes. Ensure good air circulation. Sterilize pruners between cuts if wilt is suspected. Some varieties are more resistant than others (e.g., Viticella types). The plant often recovers by sending up new shoots.
Powdery Mildew
Symptoms and Management
White, powdery patches on leaves, especially in humid conditions or with poor air circulation.
- Prevention: Provide good air circulation (proper spacing, pruning). Water at the base, not overhead.
- Treatment: Remove affected leaves. Use horticultural oil or fungicide if severe. Choose resistant varieties.
Pests (Aphids, Slugs, Earwigs)
Management
- Aphids: Wash off with water spray or use insecticidal soap.
- Slugs/Snails: Can damage young shoots. Use slug baits, traps, or barriers.
- Earwigs: Can chew holes in flowers/leaves at night. Traps can sometimes help. They are often a minor nuisance.
Conclusion
Growing clematis is a rewarding experience, offering vertical interest and spectacular blooms. Success hinges on providing the right conditions – sunny tops, cool, moist roots, and appropriate support – and understanding the crucial pruning requirements for your specific variety. Plant deeply, prune correctly, and enjoy the magnificent floral display of the Queen of Climbers.
