Credit: David Robinson
Echium wildpretii
Background and story
The Tower of Jewels (Echium wildpretii) is a striking biennial native to the subalpine zones of Tenerife in the Canary Islands, where it grows on dry, volcanic slopes around Mount Teide.
It was first described scientifically in 1902 by H. Pearson (published by Hooker) and named in honour of the Swiss botanist Hermann Wildpret, who worked extensively on the flora of Tenerife.
Like many Canary Island endemics, it entered European cultivation in the late 19th and early 20th centuries, becoming a prized curiosity in botanical gardens and later in mild coastal planting, valued for its extraordinary vertical flower spikes.
Did you know?
It flowers only once, in a spectacular final effort. The plant is monocarpic (biennial in practice), spending a year or more as a low rosette of silvery leaves before producing a single towering spike of flowers, setting seed, and then dying.
Hardiness and conservation
The recorded RHS hardiness rating is H2, which means this plant can tolerate cool conditions, but not frost. In practice, it should be treated as frost-tender outdoors. The recorded USDA/PFAF hardiness value is 9-11, which is useful as a broad winter-temperature guide, but it should not be read as a direct substitute for the RHS rating. Local hardiness always depends on local shelter, drainage, winter wet, salt-laden wind and the plant’s age and establishment.
The IUCN Red List status recorded here is Not Assessed (NA).
Additional notes for Ireland and Britain
In Ireland and the UK, Echium wildpretii is a marginal but often successful plant in sheltered, free-draining sites, particularly in coastal gardens. It forms a low rosette of silvery leaves in its first year, followed in its second year by a dense, conical spike of rose-red flowers up to 2–3 metres tall. It thrives in full sun and sharply drained soils, but is sensitive to prolonged winter wet and hard frost, typically tolerating only around −5°C to −7°C. As a result, it is most reliable in mild, coastal or urban microclimates, where it can self-seed and persist. In less favourable conditions, it is often grown as a biennial under glass or with winter protection.
From a conservation perspective, Echium wildpretii is a narrow endemic species, confined to a relatively small region of Tenerife (with a related subspecies on La Palma), and is therefore intrinsically vulnerable to environmental change. It is protected within its native range under regional conservation measures, reflecting concerns about habitat disturbance and climate change impacts on high-altitude ecosystems. Despite this, it remains widely cultivated and secure in horticulture, where its spectacular appearance has ensured ongoing popularity.
Notable features
- It is perfectly adapted to life at high altitude on a volcano. This species grows naturally at around 1,600–2,000 m on the slopes of Mount Teide, thriving in nutrient-poor volcanic soils and extreme temperature swings.
- Its flower spike is built from thousands of individual blooms. Each cone-like inflorescence is made up of hundreds to thousands of tiny red flowers, all densely packed to create the striking “tower” effect.
- It attracts both insects and birds as pollinators. Unlike many of its relatives, it is visited by bees, insects, and even birds, reflecting a more flexible pollination strategy in its harsh mountain environment.
- It is highly specialised and vulnerable despite its impact. As a narrow endemic confined largely to Tenerife, it depends on a very specific climate and habitat, making it sensitive to climate change and environmental disturbance.
Earlscliffe notes
We’ve grown this many times at Earlscliffe over the years, and with so many Echium pininana in the garden, we’ve found that after a few seasons they will occasionally hybridise with E. wildpretii.