The contorted filbert, botanically known as Corylus avellana ‘Contorta’, is a distinctive ornamental plant prized for its uniquely twisted and spiraling branches. This deciduous shrub, also commonly called Harry Lauder’s Walking Stick or corkscrew hazel, offers visual interest throughout the year, especially in winter when its gnarled form is fully revealed. Growing this plant in a container allows for flexible placement on patios or smaller outdoor spaces, making it a captivating focal point in diverse garden settings.
Container Selection and Initial Planting
Choose an appropriate container for a healthy contorted filbert. Start with a pot slightly larger than the plant’s current root ball to allow for initial growth. As the plant matures, it will need repotting into progressively larger containers.
Porous materials like terracotta promote root air circulation, while plastic pots retain moisture, beneficial in warmer climates. All containers must have drainage holes to prevent waterlogging and root rot. When planting, carefully remove the filbert from its nursery pot, gently loosening any circling roots. Position the plant so the top of the root ball is slightly above the soil line, then backfill with potting mix, lightly tamping to remove air pockets. Water thoroughly immediately after planting to settle the soil.
Ongoing Care for Containerized Contorted Filbert
Light Requirements
Contorted filbert thrives in full sun to partial shade, ideally receiving at least six hours of direct sunlight daily. Full sun encourages vigorous growth, but the plant tolerates partial sun with diffused light. Container growing allows easy adjustment of its location based on seasonal light or climate, ensuring ideal sun exposure.
Watering Practices
Consistent moisture is needed for contorted filbert, but avoid waterlogging to prevent root issues. Watering frequency depends on container size, material, and weather conditions. Smaller or porous pots may require more frequent watering than larger, less permeable containers.
During the warm growing season, keep the soil consistently moist but not saturated. Before watering, check soil moisture by inserting a finger an inch or two into the potting mix; if it feels dry, water. Water until excess drains from the pot bottom to ensure the entire root ball is hydrated.
Soil Mix
A well-draining potting mix is essential for containerized contorted filbert. This plant prefers a slightly acidic to slightly alkaline soil pH (6.0 to 7.5). A quality container potting mix, often including perlite or grit, provides necessary drainage and aeration for root development.
Avoid heavy garden soil, which compacts and retains too much moisture in containers, leading to poor drainage. Incorporating organic matter like compost can enhance soil structure and nutrient retention without compromising drainage.
Fertilization
Containerized contorted filberts need regular fertilization during their active growing season, as nutrients leach quickly from pots. Though light feeders, they benefit from supplementation.
A balanced, slow-release granular fertilizer for shrubs and trees is generally suitable. Apply in early spring as new growth begins, continuing through the growing season until three or four weeks before the first anticipated frost. Always follow product label instructions for application rates and frequency to prevent over-fertilization, which can harm the plant.
Pruning for Health and Form
Pruning maintains the contorted filbert’s shape and health. The best time is late winter or early spring, before new growth, allowing a clear view of branch structure and promoting quick healing.
Remove dead, diseased, or crossing branches to improve air circulation and prevent issues. Many contorted filberts are grafted, producing straight, non-contorted suckers from the base or below the graft line. Promptly remove these suckers, preferably by pulling them out rather than cutting, to preserve the plant’s ornamental form and direct energy to twisted growth. Selective pruning also helps manage overall size, keeping the plant proportionate to its container.
Winter Protection and Repotting
Containerized contorted filberts are more susceptible to cold damage than in-ground plants, requiring winter protection. Before freezing temperatures, move the container to a sheltered location like an unheated garage, shed, or protected wall. Insulating the pot with burlap or placing it inside a larger, insulated container shields roots from extreme cold. A 2-3 inch layer of organic mulch on the soil surface also insulates the root zone.
Repot every two to three years, or when the plant shows signs of being root-bound (e.g., roots circling the pot or growing from drainage holes). Choose a new container only slightly larger (2-4 inches wider) to avoid over-potting. During repotting, inspect the root ball and gently prune any thick, circling roots to encourage new, healthy growth. This refreshes soil, replenishes nutrients, and maintains vigor in its finite container space.
Troubleshooting Common Issues
Contorted filbert, though generally resilient, can encounter issues in containers. Leaf yellowing often indicates watering imbalance (too much or too little) or nutrient deficiency. Consistently checking soil moisture and ensuring proper drainage helps address these concerns.
Pest problems like aphids, spider mites, or scale insects may occur. Regularly inspecting the plant, especially leaf undersides, allows early detection. Small infestations can be managed by hand-picking or using insecticidal soap. Promoting good air circulation through proper spacing can deter some issues.
While generally resistant to Eastern filbert blight, some varieties are susceptible to fungal cankers (black spots or dying branches). Prompt removal of affected branches prevents spread.