Clematis 'Helios'

Clematis tangutica 'Helios' was raised in 1988 at the Proefstation voor de Boomkwekerij (Research Station for Nursery Stock) in Boskoop, the Netherlands, from a cross between Clematis tangutica and the cultivar 'Golden Harvest', and was awarded the Dutch Award of Merit that same year as the best new yellow-flowered clematis. It was the first compact alternative to the otherwise rather sprawling tangutica cultivars — with flowers and leaves just as large as those of its bigger relatives. The 5–7 cm, bright yellow bell-shaped flowers open into flat stars with four recurved tepals and a striking cluster of brown stamens at the centre; some gardeners detect a hint of coconut scent.

From May to October, the flowers appear in several waves, so that fresh blooms and the characteristic silky seed heads are often visible at the same time. At around 200 cm, 'Helios' stays noticeably more compact than most tangutica cultivars, making it well suited to smaller gardens, trellises, obelisks and containers on the patio. It tolerates sun to semi-shade and, once established, copes well with drier spells — but avoid heavy, waterlogged soils.

'Helios' is reliably hardy (zone 6, -23.3 to -17.8 °C). Cut the plant back to about 25 cm in March (pruning group 3) — this keeps it compact and encourages vigorous new growth and abundant flowering. A practical tip: propagate 'Helios' from cuttings rather than seed, as seedlings often vary in growth and flower quality.