Euphorbias

Genus Euphorbia

Note: All Euphorbias exude a white milky sap if damaged. This sap can irritate the skin.

The family Euphorbiaceae is the sixth largest family of flowering plants on the planet. The genus Euphorbia makes up by far the greatest proportion of the family, and with 2160 known species it is the second largest plant genus in the world.

Euphorbia species can be found growing on every continent except Antarctica, exhibiting a huge range and variety of forms and plant types, from annuals and biennials to leafy perennials, woody shrubs and trees, and many succulents. Of the hardy leafy perennials that we grow in our gardens; most come from Europe, the Middle East and temperate Asia including the Himalaya. Many are evergreen and provide excellent foliage colour and interest throughout the winter.

Euphorbia myrsinites-evergreen foliage

Euphorbia myrsinites-evergreen foliage

Euphorbia Excalibur-emerging foliage

Euphorbia Excalibur-emerging foliage

Flowers

All Euphorbia flowers are unique in having neither petals nor sepals. The main floral colour comes from a modified leaf known as a cyathium leaf (but commonly called a bract). These colourful leaves do the job of the petals. They attract insect pollinators and can be lime, yellow, gold, orange, or red in colour depending on species and varieties.

Euphorbia griffithii 'Fireglow'

Euphorbia griffithii 'Fireglow'

Euphorbia palustris

Euphorbia palustris

Nectaries

The reproductive part of each flower also contains nectar rich glands (each called a nectary), which provides the insect pollinator’s reward. These nectaries can vary in colour and can be yellow, orange, red, maroon, brown or black. In some species – most notably E mellifera, the nectaries give off a strong sweet perfume. The main flowering period is April to June but there are species that flower throughout the summer.

Euphorbia x martinii

Euphorbia x martinii

Euphorbia rigida

Euphorbia rigida

Seed Pods

After pollination, the ovary swells and ripens into a three-sectioned fruit capsule, each section containing one seed. These seed capsules are roughly spherical in shape but can vary considerably from species to species. They remain on the plant; drying and shrinking until they burst open with an audible crack and propel their seeds in all directions.

Cultivation

Growing Euphorbias is on the whole quite easy. They will grow in most soils providing it is friable (sandy, gritty, loamy but not clay) and will tolerate a wide range of pH values. As a general rule they will be happy with some sun, shelter and reasonable drainage.