The latest go-to plant tolerates heat, dryness and cold

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Euphorbia rigida has become quite the go-to plant.

Euphorbia rigida has become quite the go-to plant.

Credit:Megan Backhouse

Any day, I am going to nudge out some of the self-sown Euphorbia rigida that’s about to be trampled underfoot on my gravel pathway and deposit the perky blue-green seedlings on higher ground. It’s not the first time and it won’t be the last. When I planted just three tiny plants five years ago, I didn’t know what I was unleashing.

Ever-widening outcrops are erupting not just on the path but also in bare snatches of garden bed, between rocks and in the gravel mulch. It’s always a pleasure to see them. Even at this time of year when much else is drying and draining of colour, Euphorbia rigida sails on, its waxy leaves casually winding around its stems in perfect spirals.

Unruffled by heat, tolerant of dryness and impervious to the cold, this relatively low-lying spurge is what you would call a good-doer. In the middle of winter it is ablaze with yellow flowers – actually modified leaves called bracts – that in early spring turn green then pink and then dark crimson. Coupled with the evergreen foliage, it’s a non-stop display.

This spurge is a plant for all seasons. And, as more of us have started to ease off on the watering and as our tastes have edged towards the silver and sculptural, it has become quite the go-to plant.

Garden designer Michael McCoy recently singled it out as a plant he couldn’t do without in his Woodend “steppe” garden, while nurseryman David Glenn has described it as “a mainstay” of the dry garden at his Ascot nursery. The one Glenn grows is from seed collected from north of Sparta in Greece. “So I knew it was going to be tough,” he told a recent gardening conference.

Euphorbia rigida is unruffled by heat, tolerant of great dryness and impervious to the cold.

Euphorbia rigida is unruffled by heat, tolerant of great dryness and impervious to the cold.Credit:Megan Backhouse

At 60cm tall, it’s not the biggest euphorbia on the planet but nor is it the most diminutive. The genus Euphorbia is vast and diverse and contains more than 2000 types.

Some euphorbias are trees, some are shrubs and some are small annuals. There are euphorbias that are weeds and there are euphorbias that look like – but actually aren’t – cacti and there is one (Euphorbia pulcherrima or poinsettia) that is synonymous with Christmas.

But what all euphorbias have in common is a particular floral structure that includes neither sepals nor petals, or other typical flower parts. Their other shared trait, this one more problematic for gardeners, is the milky white sap that exudes from their broken stems and leaves that can cause an intense burning sensation on bare skin and eyes. Gardeners are advised to wear gloves and eye protection when handling them and even then, be warned, when you cut a stem – particularly of that old-time garden stalwart Euphorbia characias subsp wulfenii – the sap can actually squirt up towards you.