Euphorbia x martinii 'ASCOT RAINBOW' spurge

Do you enjoy the kaleidoscope play with shapes and colours? The foliage of the Ascot Rainbow spurge behaves in much the same way, especially in autumn and winter. This garden jewel was discovered by David Glenn in Victoria, Australia, in 2005 as a spontaneous branch sport of an unnamed Euphorbia × martini plant, and he named it after his hometown. Its evergreen leaves change colour not only with the seasons but also in response to stress. In summer, they are predominantly grey-green with creamy yellow margins; in autumn, pink and purple shades appear, especially at the tips; and in winter, the whole plant turns a deep pinkish-red with rich yellow centres. This colour shift can also be triggered by drought, when the plant protectively withdraws chlorophyll into its roots, while overfertilization (especially with nitrogen) suppresses the multicoloured effect and emphasizes green tones instead.

‘Ascot Rainbow’ forms a compact, dome-shaped, slightly spreading habit with sturdy red stems, reaching up to 90 cm in height and 80 cm in width. Flowering is abundant. From spring into summer, the plant produces tubular flowers in cream, lime, green, and red, so distinctive that for one or two months they completely transform the visual character of the shrub – or rather subshrub, since these spurges are botanically known as semi-woody perennials. The cultivar is protected by patents PP21,401 (USA – 2010) and 68088 (Europe – 2011).

‘Ascot Rainbow’ combines beautifully with dark-leaved perennials such as heucheras, salvias, or sedums. In the background, it pairs well with simple evergreen shrubs like ilex, leucothoes, or pieris, while the foreground can be filled with small spring bulbs that highlight the foliage’s early-season colours. Thanks to its architecture and constant variability, it works equally well as a stand-alone specimen or as a contrasting element in a mixed border.

Euphorbia amygdaloides and its hybrids are woody perennials typical of the warmer, though not arid, regions of the Caucasus and Turkey. They tolerate high summer temperatures but require more moisture than the drought‑adapted vegetation of southern European rocks and plains. This explains their great popularity in Great Britain, where the consistently high humidity allows spurges to thrive. In our continental conditions, Galaxy Glow does best in moderately moist but well‑drained soil of any pH. It should be kept lightly moist for the first few months, but beyond that they will rarely need more water than natural rainfall provides, especially if mulched. Feeding before flowering, and again at the end of summer is beneficial, though not essential. Ascot Rainbow is reliably hardy to at least –25 °C and requires no winter protection. It is not suitable for outdoor planters, as it dislikes sudden fluctuations in temperature and moisture.

Last update: 08-12-2016; 02-10-2025