Plant Profile: Kniphofia

close-up: Kniphofia Sunningdale Yellow blossoms

Glowing inflorescences of Kniphofia hovering above the foliage layer of perennial plantings are a striking and dramatic effect available to the urban designer. Besides their vivid blooms in a range of colours from red-orange to yellow-green, Kniphofias’ great value in city plantings lies in the robustness of their flowering stems at a variety of heights. No other perennial with emergent flowerscapes is so resistant to strong winds and knocks, sturdy enough to be used even in narrow ribbon-type plantings alongside sidewalks and roads.

Most of the genus’s c.70 species grow in South Africa. Of most interest to temperate specifiers are the hardy species from the mountains of the Eastern Cape, including the late-flowering K. bruceae, K. caulescens, K. linearifolia, and K. rooperi.

Hybridisation is common even in the wild, and the complex parentage of the 900+ cultivars mean that traits such as hardiness and flowering period are difficult to predict from appearance—a challenge, but also an opportunity for innovation.

Adapted to high summer rainfall and cold, dry winters, the hardy species cope well with drought (thanks to the rhizome and fleshy roots) and, in many cases, seasonal inundation.

Kniphofias’ performance in traditional garden border cultivation has earned them a well-deserved reputation for disliking winter wet, but the sharp drainage of engineered urban soils may significantly improve their chances of weathering freezing European conditions.

Some species (e.g. K. caulescens) actually favour poorly drained sumps and bogs, and in Northern England, the cultivars ‘Percy’s Pride’ and ‘Tawny King’ are included in the semi-wet perennial specification for Sheffield City Council’s influential “Grey to Green” SUDS retrofit.

Adapted to high-altitude grassland, Kniphofias associate well with ornamental grasses. A long flowering succession is possible using different hardy varieties, from the short K. hirsuta ‘Fire Dance’, through to the appropriately named K. ‘Christmas Cheer’.

By Martin Deasy, a tutor on the RHS Mhort. He also runs his own landscape design business.

This article was first published in the October 2023 edition of FloraCulture International.