Gromwell 'Heavenly Blue'

'Heavenly Blue' is perhaps one of the most popular alpine plants in the UK, and for good reason. It forms a low-growing, spreading mat of small, hairy, evergreen leaves that are smothered in late spring and early summer by flowers of a truly startling, intense Gentian-blue. It is an excellent choice for cascading over walls, covering sunny banks, or filling gaps in a rockery. Unlike many other alpines, it is strictly calcifuge and requires acid to neutral soil; it will quickly turn yellow and fail in lime-rich conditions. It prefers a sunny position but likes its roots to stay reasonably cool and moist. In the UK, it can be prone to becoming 'leggy' or dying off in the centre if left for many years, so a light prune after flowering can help maintain its vigour. It is a fantastic plant for providing a massive impact of colour and is relatively easy to grow for those with the right soil type.

Sun: Full sun.

Soil: Well-drained, acid to neutral soil.

Hardiness: H5 — down to −15°C.

Flowering: May, Jun, Jul.