Hypericum undulatum: complete guide

Overview

Hypericum undulatum, commonly known as wavy St. John's-wort, is a robust, evergreen plant from the Hypericaceae family. Native to Macaronesia, West and Southwest Europe, and North Africa, this plant thrives particularly well in Mediterranean climates. It is an ideal choice for groundcover, borders, and xeriscaping applications.

Appearance and bloom

Hypericum undulatum is a compact grower reaching 30 to 60 centimeters in height. The leaves are small, lance-shaped, and have a characteristic wavy (undulate) margin along the edges. In summer, numerous golden-yellow flowers with prominent stamens appear. The flowers attract bees and other pollinators and bloom over an extended period.

Ideal location

This plant thrives in full sun to partial shade. A minimum of 6 hours of direct sunlight daily is ideal for maximum flowering. The plant also accepts light shade, though this may result in fewer flowers. Windy, open locations are suitable; the plant is very wind-resistant and tolerates exposure well.

Soil

Hypericum undulatum is not fussy about soil type. It grows well in poor, dry soils, sand, and even rocky areas. It prefers well-draining, nutrient-poor soils and tolerates low nutrient levels. The plant does not grow well in heavy, waterlogged soils. Slightly acidic to neutral pH (5.0-7.0) is ideal.

Watering

Once established, Hypericum undulatum is highly drought-tolerant. It accepts rainwater and can grow without supplemental watering during dry periods. Young plants should be watered regularly until well-rooted. Avoid overwatering, as this causes root rot. Dry to moderate moisture is ideal.

Pruning

Pruning helps maintain shape. After blooming, spent flower stems can be removed. Light shaping is possible in spring. Avoid heavy pruning as it may reduce flowering. The plant responds well to regular, light maintenance pruning.

Maintenance calendar

Spring: Plant in dry, well-draining soil. Light pruning possible. Summer: Water only in extreme dry periods. Flowers appear. Minimal maintenance. Autumn: No special care needed. Plant is drought-tolerant. Winter: In milder areas, the plant continues to grow. In colder zones, some damage may occur.

Winter hardiness

Hypericum undulatum is hardy to approximately -5 to -10 degrees Celsius. In temperate zones, it survives normal winters well. In severe cold, damage may occur. Mulching provides protection in borderline zones. The plant is semi-evergreen and retains some leaves in winter.

Companion plants

Combine with other Mediterranean plants such as Cistus, Lavandula, and Thymus. These create beautiful, drought-tolerant combinations. Low-growing plants like Sedum and succulents make good companions. Hypericum also works well in gravel or rock garden settings.

Closing

Hypericum undulatum is an exceptional choice for warm, dry gardens. With its golden-yellow flowers, drought and wind resistance, it offers years of minimal-maintenance beauty. Perfect for Mediterranean and xeriscape gardens. Plant in masses as groundcover or use as an accent plant. Many garden centers stock this species. For more garden ideas, visit gardenworld.app.