Euphorbia: How to grow and look after euphorbias in your garden

By Katie Beale

Published: Sunday, 20 February 2022 at 12:00 am

Euphorbias are striking plants, ranging from small, low-growing annuals to large, structural shrubs and succulents. They are extremely useful garden plants, and there is a euphorbia for almost every situation. They are grown for their spring interest in the form of their new growth, stems and flowers, for their evergreen architectural value and for their surreal, ‘other worldly’ appearance.

Euphorbias’ natural habitats range from Macaronesia to the Himalayas. They vary in size from stiffly upright to prostrate and spreading, with a height of between 10cm to 2.5m and a similar spread.

Euphorbias work well in many different planting schemes. Those preferring hot, dry conditions grow well in gravel gardens among lavenders, salvias, cistus and Mediterranean bulbs, such as alliums and nerines.

E. amygdaloides ‘Purpurea’ creates a wonderful contrast with the ornamental grass, Milium effusum ‘Aureum’ while the bold architectural domes of E. x pasteurii ‘John Phillips’ and E. mellifera are perfect specimen plants in an exotic border where their foliage combines well with cannas, hedychiums and dahlias.

Shade-loving euphorbias look great planted with other woodland or shade loving plants, such as dicentra (Lamprocapnos), erythroniums and corydalis.

PLANT PROFILE

What Annuals, perennials, shrubs or succulents. Origins Their natural habitats range from Macaronesia to the Himalayas. Season Early spring to autumn. Size Variable, from stiffly upright to prostrate and spreading, with a height of between 10cm to 2.5m and a similar spread. Conditions Some prefer free-draining soil in hot sunshine while others flourish in moist or dry shade. Hardiness RHS H3 to RHS H7, and from USDA 6a to 11.

*Holds an Award of Garden Merit from the Royal Horticultural Society. †Hardiness ratings given where available.

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Where to grow euphorbias

Euphorbias can be found growing in a range of habitats, from Mediterranean scrub to cool temperate woodland, in acidic or alkaline soil. Some therefore prefer free-draining soil in hot sunshine while others flourish in moist or dry shade. Depending on the species, their hardiness varies from RHS H3 to RHS H7, and from USDA 6a to 11.

How to prune euphorbias

Once the bracts of Euphorbia x pasteurii, E. amygdaloides, E. mellifera and E. Blackbird (= ‘Nothowlee’) have turned brown, cut off the dead growth to the first ring of leaves below.

E. x martini and E. myrsinites have two types of stems; those from the previous season on which the flowers appeared, and the new season’s growth. Cut out the stems that flowered the previous year down to ground level in late summer or autumn.

Herbaceous perennials, such as E. cyparissias, E. griffithiiand E. sikkimensis, should be deadheaded after flowering then cut back to ground level before the first frosts.

How to propagate euphorbias

You can propagate euphorbias by taking basal cuttings from young, non-flowering shoots in mid-spring, but wear protection while doing so, as the sap can irritate skin and eyes. Select and remove material early in the morning and put it in a polythene bag straightaway to prevent it drying out.

Take cuttings 7-10cm long, making a cut at the base with a sharp knife.
Remove the lower leaves, dip the cut in ground charcoal to seal the wound.
Knock off the excess, make a hole with a dibber or pencil into a pot of 50:50 mix of sieved peat-free compost and perlite or cutting compost, and water.
Put the pot in a propagator with bottom heat of 18-24oC in bright but not scorching sunlight.
Keep the compost moist, removing dead, diseased or dying material daily. Rooting takes up to a month.

After rooting, harden off the cuttings and re-pot them into individual pots before transplanting outdoors. Many species self-seed in gravel borders or cracks in paving (cultivars must be propagated vegetatively as they do not come true from seed). They can also be divided in early spring, using a sharp knife, though the woody roots can make this challenging.