Clematis 'Alba Plena'

Clematis florida 'Alba Plena' is one of the oldest double-flowered clematis in cultivation: it arose as a spontaneous sport of the classic Clematis florida var. sieboldiana and was already grown in Japanese gardens before 1812. Its 8-12 cm flowers are fully double, forming a strikingly regular rosette of narrow, white tepals. Unlike its better-known bicoloured sister form with a purple centre, 'Alba Plena' keeps its inner ring of transformed stamens white to softly greenish throughout – the blooms take on a faint green tinge, especially in autumn.

At around 200 cm, 'Alba Plena' stays compact enough for containers, trellises and smaller supports on a house wall. It flowers from July to October, providing double blooms well into autumn, when many other climbers have already finished for the season. Choose a warm, sunny, sheltered spot with moist but well-drained soil – keep the roots and base of the plant cool and shaded with ground cover or under-planting. 'Alba Plena' also makes a lovely cut flower.

'Alba Plena' is noticeably less hardy than most other clematis in our range (zone 9, -6.6 to -1.2 °C) and needs a sheltered position; in exposed areas, growing it in a large container that can overwinter frost-free is the safest choice. After the first flowering, cut the plant back to about 100 cm in June; in early spring it is enough to remove dead and weak shoots. Because 'Alba Plena' is prone to mutation and difficult to propagate, it remains a rarity for attentive collectors – the patience needed while it establishes is rewarded with one of the most beautiful double clematis flowers of all.