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Euphorbias

A sense of Euphorbia

Euphorbias are one of my favourite plant families. They have their downside (poisonous, irritating sap) but we all have relatives like that, don’t we?

Here’s my top five:

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.

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, very architectural looking and great as a contrast to grasses, etc. In good conditions, it will grow to 1-1.5 metres, with a similar spread. Hardy down to -5C. They’re more at risk of frost damage in pots, or from sudden, early frosts, so beware. Despite my initial worries, it’s been absolutely fine here in NE England – plant it with added grit for good drainage in winter.

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.

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 a light soil, you may find it a little invasive.

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. I’ll watch with interest as the season progresses.


potted-guide-logoPotted guide: Euphorbias from seed

It’s worth having a go at growing Euphorbias 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 unnamed rarities. They range from 45cm-1.2m, are all hardy perennials, price £3.15.

Mixed Euphorbias
Mixed Euphorbias in a seedbed

I sowed mine in spring on to a good soil-based compost and covered with Perlite to approximately their own depth.

They were kept at 15 to 20 degrees C, pricked out into modules, then potted on and hardened off outside, then planted into a nursery bed.

The following spring, they were all were moved to their final positions.


Pruning guide: mind the sap!

Euphorbia characias subsp. wulfenii
Long-lasting bracts on Euphorbia characias subsp. wulfenii

All Euphorbias 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 after flowering, cut out all flowered stems at the base, leaving new growth to shoot up.

If you hack everything down to the ground, you’ll lose next year’s flowers.