I have always gardened with euphorbia and it would be hard to imagine removing them from my planting palette. Look at the tribe as a whole and they span several continents, shape-shifting within their huge genus as they navigate their chosen habitat. They have adapted to cool, leafy woodland, wet stream edges and modified their surface areas and foliage so that they can withstand extremes of drought and exposure in their most succulent incarnations. For this reason they are a genus that I return to in my uncertainty about what will happen next with our ever-changing climate and need to be adaptable.

The spurges are included in almost all the plantings in the garden here, though you might not always be drawn to them first, when they are sitting back and out of season. Their season is long and varied and their particular vibrancy is something that always brings with it new energy when they come into flower.

The creeping Euphorbia cyparissias ‘Fen’s Ruby’ is one of the first to emerge at the end of the winter. Its searching, rhizomatous growth is not unlike the colour of young sea kale, a soft plum-purple with a bloom that makes it at first recessive until, in early April, it rallies to flower. Very quickly, in tandem with the spring surge, the ground plane it occupies is suddenly a froth of brilliant lime green. Humming with first bees and smelling sweetly of honey, I team it with Tulipa orphanidea (Whittallii Group) and let it run amongst later-to-emerge perennials that can cope with its opportunistic behaviour. Happiest in a free-draining position, it can be devilish, moving easily in and out of the shadows to surprise you in a new position where it will favour the sun. For this reason I give it a place where it cannot escape. Some boundaries made by a path or a wall or it will be everywhere. Pulling it must be done with care and with gloves, as the milky sap of all euphorbia makes your skin photosensitive, causing it to burn when exposed to sunlight.

I am generally careful with plants that run, so most of the spurges I choose to work with are clump-forming, but I do make exceptions when I know I can manage their limits. Curbed for being baked in the summer in the main garden, I will persist in trying to establish E. griffithii ‘Dixter’ on the lowest parts of the slope where the moisture holds. Happiest where it can live well, I have used it extensively in one of the mingled plantings at the Tokachi Millennium Forest to inject its hot tomato red en-masse. The vibration provided by the colour literally races your pulse until the fiery bracts dim once spring passes into summer. It has a second moment again in autumn when the foliage colours orange and butter yellow, but if it likes you too much it is not a plant for the faint-hearted.

Safe for being clump-forming and capable of living in soil that never dries out is the Marsh Spurge, E. palustris. We grow this here in the seeping, wet clay of the ditch and it is strong enough to cope with the competitive marshlanders. I gave it two years of care to help it establish by giving each plant a mulch circle and keeping the grass cut immediately around them, but once they get their roots down, they are hearty enough to race ahead of the native grassland. The vibrant, acid-green flowers begin just as the Marsh Marigolds go over and top out at about a metre to coincide with the native yellow flag iris. I love this plant and the way it connects back to the garden above it where, once the perennials begin to touch and you can no longer see the soil, E. cornigera and E. wallichiana have their moment.

Euphorbia cornigera and E. wallichiana (main image), at first glance are not dissimilar. Both form sculptural cushions of bottle green foliage with a silvery midrib and impressive heads of acid green flower that are at their most luminous with the sky-blue Siberian Iris. In full flight the plants are a metre across and a little more in height, but they never need staking. In my experience E. cornigera is the more elegant of the two with more space in its limbs and with flowers that open up as they age and their green dims. Both have started to seed about now and occasionally into the crowns of other plants, where they soon out-manoeuvre the sanctuary provided by their host. So the seedlings need watching, but are easily winkled out using the memory of their fully grown parents as a guide when weeding.

For the first few years after planting the garden, the shrubby Euphorbia ceratocarpa was easy here. Light of limb, lime-green in all its flowering parts and continuing from Easter through to the end of the year, it did well until the harsh winter of the one before last. Several plants regenerated from the base after their top growth was blackened, but most failed and have been difficult to reintroduce, because the garden has matured and there is less light reaching the ground to establish young plants. As is the often-magical way with failure in a garden there has been a rash of young seedlings since we lost the original plants. These have all appeared in the paths and have shown me their Sicilian heritage in a preference for open ground and being on the edge of things. I have used this wonderful euphorbia along the central path at Delos in Sissingurst and plan for the scarlet Anemone pavonina to one day seed amongst it. Lime green and scarlet and the buzz they offer to spring.

I have removed several Euphorbia characias here, as they grow too unruly on our hearty soil, but I have plans to reintroduce them on the margins of the sand garden where they should be more at home in less fertile ground. In Greece, where it grows wild, Euphorbia characias can be found both in the open and also the cool of shady ravines, so they can take a little shadow,  but they do best here and form the most architectural plants in an open position and on free-draining ground. Handsomely clothed in blue-green foliage, the evergreen shoots are sent from the base not long after this year’s flowers begin to go over. This is when you need to don your gauntlets and  cut the old growth to the base to make way for the new. They then stand smart for the rest of the year until, at the end of the winter, the top growth cranks its tip where the flower is forming. By the height of spring, the summit of each growth is crowned with a flower the size of a pineapple. Cassian Schmidt, the former Director of Hermannshof in Germany gave me cuttings of a more modestly growing form called ‘Sisco’, which I have waiting in the frame for the banks above the sand garden on one of our hottest slopes. I plan for them amongst magenta cistus where the sun bakes.

Words: Dan Pearson | Photographs: Huw Morgan

Published 20 April 2024