Enjoy a sense of euphorbia in your garden
Hardy euphorbia are part of one of my favourite plant families, the spurges. They have their downside (poisonous, irritating sap), but their presence, stature and zingy colours will liven up any garden. I’m only covering hardy varieties here, not the tender types you often see from cacti and succulent specialists. Here are my favourites…
Hardy euphorbia – E. characias subsp. wulfenii
An erect, sparsely branched medium-sized sub-shrub with oblong, grey-green leaves and large, rounded heads of lime-yellow flowers. It’s very architectural looking and a great contrast to grasses, etc. It will grow to 1-1.5 metres, with a similar spread. Hardy to -5C. They’re more at risk of frost damage in pots or from sudden, early frosts. My plant has been fine in NE England. Plant it with added grit for good drainage in winter.
E. polychroma Purpurea
Very early yellow-green bracts with purple-tinged leaves. This Euphorbia prefers to be planted in partial shade in moist, well-drained soil and grows to just 40cm. Some of the other purple-leaved varieties are absolute martyrs to mildew. This one seemed OK until a couple of dry weeks at the beginning of March, when it succumbed to powdery mildew, but it did recover quickly. However, in subsequent seasons, it proved to be a martyr too!
E. mellifera (Canary spurge)
I grew this incredibly handsome, tropical-looking Euphorbia from a packet of mixed seeds (see below). It’s a dome-shaped evergreen shrub with narrow, bright green leaves. They are highlighted with a cream mid-rib. In late spring, honey-scented, brownish flower heads are produced, followed by green, pea-like, poisonous fruits. Height 1.5-2.5m, although mine is at the lower end of that scale. Hardy to -5C. I do cover it with fleece if heavy frosts are forecast.
Hardy euphorbia – E. griffithii Fireglow
A vigorous perennial that will spread through ground cover plants with upright stems clothed in narrow, red-tinged leaves and orange-red flowers in early summer. Mine bursts its way through golden marjoram and Arabis. Also, has great autumn colour. It’s hardy, with a height of 0.5-1 metres, and a similar spread. If you garden on light soil, you may find it a little invasive. Even on my clay soil, I’m forever pulling out runners.
Euphorbia x martinii Ascot Rainbow
A must for late winter/spring colour. It forms a neat, evergreen clump of slender blue-green leaves, edged creamy yellow, flushed with red in colder weather. Spikes of cream, lime and green flowers later in spring. It only grows 50-60cm high and will tolerate light shade. Not a lover of heavy soil, it does best when planted in well-drained soil and is great for winter containers. This is the only so-called hardy euphorbia I have grown that didn’t survive the winter – the Beast from the East did for it!
Hardy euphorbia – E. myrsinites
An evergreen groundcover plant, hardy with exotic looks. Succulent-like leaves that sprawl on blue-green stems. The typical lime/yellow flowers appear in spring to early summer. It does best in full sun, growing to just 10cm high, but with a spread of 0.5m per plant. A bit of a takeover merchant, but ideal if you want quick ground cover. It has been a lifesaver in my front garden, which is bone dry and covered with large gravel chunks.
Potted guide: Growing hardy Euphorbia from seed
- It’s worth having a go at growing Euphorbia from seed. I bought Euphorbia Mixed from Plant World Seeds. They germinated easily, and I now have loads of plants, some of which flowered in the first year. There are some I can’t identify, but the mix does contain some named rarities, including E. mellifera. They range from 45cm-1.2m, and are all hardy perennials.
- I sowed mine in spring onto a good soil-based compost and covered it with Perlite to approximately their depth. They were kept at 15-20°C, pricked out into modules, potted on and hardened off outside, and then planted into a nursery bed. The following spring, they were all moved to their final positions.
Pruning hardy euphorbia – mind the sap!
All Euphorbia have a white, toxic, milky sap that causes an itchy rash and possible blistering on contact. Getting sap in your eyes is painful and can even cause blindness.
Gloves and protective clothing are a must when trimming back. The bigger E. wulfenii types tend to get very leggy and untidy. Most Euphorbia species bloom at the tips of stems that grew the year before. The general rule of thumb is to cut out all flowered stems at the base after flowering, leaving new growth to shoot up. You’ll lose next year’s flowers if you hack everything down to the ground.
