Clematis tangutica Helios

Clematis tangutica 'Helios' is a vigorous clematis whose ancestors roamed the thickets from Mongolia to China, up to an altitude of 4900m (16076ft), taking on the appearance of vigorous climbing plants or bushy shrubs in drier areas. It amazes with its long and beautiful flowering period that starts in May-June and ends very late in the season, offering curious bright yellow campanulate flowers composed of fleshy petals that open fully to reveal a heart of purple-dark anther stamens. Its feathery and silvery fruits are extremely decorative. Like many clematis, it appreciates having cool roots in well-drained soil, with its head in the sun. It is one of the hardiest and most generous, both in the garden and in pots.

Clematis tangutica 'Helios', sometimes marketed under the name C. 'Radar Love', is sometimes nicknamed Tangut clematis. This form, slightly more compact than the species and with larger and more colourful flowers, was discovered in 1988 in a research station in Boskoop, Netherlands. All clematis belong to the Ranunculaceae family.

'Helios' is a woody, deciduous climbing plant, clinging to its support through petioles transformed into tendrils. Its stems will reach 3 to 5m (10 to 16ft) in length, with a ground coverage of 1 to 2m (3 to 7ft), so a strong support will be required to accommodate the plant's volume and weight. Flowering on the current year's shoots is very long: it timidly starts in May, reaches its peak in July-August, and then continues more sporadically until October. Its trailing flowers, 6 to 8cm (2 to 3in) wide, are composed of 4 large, thick and waxy petals with turned-up edges, in canary yellow, surrounding a heart of purple-dark stamens. They are solitary or grouped in 2 or 3 in the axils of the leaves. The flowers give way to fluffy and silky fruits, 8 to 10cm (3 to 4in) wide, composed of seeds with persistent styles in the form of long silver filaments. The foliage offers a rather unusual aspect: it is composed of dark green leaves singularly cut into toothed petioles measuring 2 to 6cm (1 to 2in).

This clematis is capable of flowering 3 months after being sown. It will quickly cover a trellis or a fence. It can also cover a shrub with dark foliage (Black Lace Elderberry, purple hazelnut) or with beautiful autumn colours (deciduous spindle tree, smoke tree, or witch hazel). It can also dress up a slightly neglected embankment, like a blue periwinkle with which it will blend well. The unique beauty of its flowers, their abundance, and the duration of the flowering make this clematis a star of the garden and patio. It can, for example, be planted with a climbing rose, preferably a perpetual one with yellow or orange blooms like Rosa 'Ghislaine de Féligonde', with creamy-white like R. 'Iceberg', or with mauve flowers like R. 'Purple Skyline'. It can also elegantly dress up a dead tree.