Euphorbias: to plant, to grow and to maintain

Botany

With over 2,000 species, euphorbias form an enormous and extremely varied group. They have a wide global distribution, being found in both temperate and tropical regions. They grow in Africa, Asia, Europe, and the Americas. Many species can be found in France. The small Euphorbia peplus is common in gardens, cities, and on pavements… One can also easily encounter Euphorbia helioscopia, Euphorbia amygdaloides, or Euphorbia cyparissias in the wild.

Most cultivated euphorbias are perennials, but there are also annuals (like Euphorbia marginata) and biennials (Euphorbia lathyris). Some euphorbias are grown as houseplants (notably succulent species…).

Euphorbias were named in honour of Euphorbus, physician to King Juba II of Mauretania (1^st century BC). He is said to have discovered the toxic and medicinal properties contained in the latex of these plants.

Euphorbias are truly unique plants, with their own characteristics. They have given their name to the family Euphorbiaceae, which includes acalyphas, crotons (Codiaeum variegatum), castor oil plants, and mercurials… as well as some utilitarian plants, such as Manihot esculenta, which produces cassava, and Hevea, a tree whose latex is used to produce rubber. Euphorbiaceae are mainly found in tropical and subtropical regions.

Euphorbia cyparissias: botanical illustration

Euphorbias are truly polymorphous plants: they take on very diverse forms. Some are small herbaceous plants with a thin habit, while others are arborescent, reaching up to 20 m in height, and some resemble cacti… What unites them is their sap, the white latex that flows from their tissues. This is almost their only common point.

Euphorbias therefore take on extremely varied forms. Regarding species commonly cultivated in gardens, Euphorbia characias have a shrubby habit and sometimes exceed 1 m in height. Others, like Euphorbia myrsinites, have a creeping, prostrate habit. Some can thus be used as ground cover. Many euphorbias, like Euphorbia polychroma, form beautiful well-rounded clumps. It is common for euphorbias to have a silhouette that is wider than tall. They often have a rather voluminous and dense appearance. Euphorbias cultivated in gardens typically measure between 20 cm and 1.20 m in height.

Some euphorbias stand out for their originality. For instance, the crown of thorns (Euphorbia milii) is distinguished by its spiny branches and beautiful bright red flowers. The very colourful Euphorbia pulcherrima (Poinsettia, or Christmas Star) is notable for its decorative red bracts.

Among the succulents, one can mention the large Euphorbia canariensis and Euphorbia candelabrum, which resemble cacti, as well as Euphorbia ferox, which can also be mistaken for a small cactus, or Euphorbia obesa, which has a very cylindrical, globular shape.

Euphorbias contain a white latex in their tissues, which flows when a stem or leaf is broken. It is very irritating to the skin and toxic if ingested. One should avoid rubbing the eyes after handling the plant.

Depending on the varieties, euphorbias flower in spring or summer. The earliest bloom from March-April, while the later flowering species finish in August-September. Euphorbia pulcherrima, also known as Poinsettia, is unique in that it flowers in mid-winter, earning it the name Christmas Star.

Euphorbias have very particular inflorescences, quite strange, called cyathes. They are gathered in cymes, resembling somewhat to umbels, and are generally borne at the tips of the upright stems. Each inflorescence (cyath) consists of a central female flower with a style, and male flowers, each with a stamen. All of this is surrounded by large bracts, which take the form of a cup. The flowers are extremely reduced, lacking sepals and petals. The inflorescence also typically contains four to five nectar glands, often crescent-shaped.

The inflorescences of euphorbias generally have beautiful bright, fresh colours, in vivid yellow or green tones. Euphorbia griffithii (notably the variety ‘Fireglow’) boasts a striking orange-red bloom.

In Euphorbia pulcherrima, it is not the flowers that are decorative, but the large red bracts surrounding them. In other species, such as Euphorbia corollata or Euphorbia fulgens, the bracts surrounding the flower have transformed to take the shape of petals. Thus, the flowers give the impression of having five ordinary petals. The species Euphorbia hypericifolia also stands out for its very different appearance from other euphorbias! It bears countless small white flowers, giving the plant a airy and light style. Here too, it is the bracts that are decorative.

The original flowering of euphorbias! Euphorbia pekinensis (photo Dalgial), Euphorbia characias (photo Joan Simon), and Euphorbia corollota (photo Joshua Mayer). The flowers of Euphorbia corollata seem ordinary, but the “petals” are actually modified bracts, as euphorbias do not possess petals or sepals.

The leaves of euphorbias are simple, undivided, with a lamina that has an entire margin. They generally have an elongated shape (ovate to linear), but their size is extremely variable. They can be thin or fleshy, thick, and are often alternate.

Euphorbias can be deciduous or evergreen. Some species lose their leaves in winter while others retain them all year round.

The euphorbia lathyris has long, thin leaves arranged in a cross, very regularly. The Euphorbia myrsinites is appreciated for its beautiful, pointed, blue-green leaves, arranged in a spiral around the stem. The euphorbia pythiusa has very small, fine leaves arranged all around the stem, somewhat reminiscent of fir foliage. Some euphorbias (notably succulent forms) have the characteristic of bearing thorns instead of leaves, like cacti.

Some euphorbias are truly interesting for the colours of their foliage! There are variegated varieties, such as ‘Tasmanian Tiger’. Euphorbia ‘Ascot Rainbow’ is very colourful: the young leaves are red, and then turn green, edged in yellow. The leaves can also be dark purple, as seen in Euphorbia amygdaloides ‘Purpurea’, which beautifully highlights the flowering. More surprisingly, Euphorbia dulcis ‘Chameleon’ has a hue that changes throughout the year, becoming purple in autumn. We also appreciate Euphorbia griffithii for its foliage that becomes vibrant in autumn.

The foliage of euphorbias takes on various shapes and colours. Euphorbia lathyris (photo J.H. Mora), Euphorbia amygdaloides ‘Ascot Rainbow’, Euphorbia myrsinites and Euphorbia ‘Black Bird’

Some euphorbias spread widely thanks to their creeping rhizomes. This is the case, for example, with Euphorbia amygdaloides ‘Robbiae’, which can form beautiful colonies, or Euphorbia cyparissias. It may be necessary to stop the expansion of these euphorbias.

The fruit of the euphorbia is a rounded capsule, attached to a peduncle. When ripe, the capsule explodes, opening in three parts, and then expels the seeds around the plant. It is quite common for ants to disperse the seeds, thanks to the presence of elaiosomes (a growth attached to the seeds that is appreciated by ants).

The fruits (capsules) of Euphorbia dendroides (photo Gideon Pisanty), and the fruits and seeds of Euphorbia paralias (photo Roger Culos – Museum de Toulouse)

Most garden euphorbias are quite hardy. Others, like succulent euphorbias, can be grown indoors or in a greenhouse.

The main varieties of euphorbias

Varieties that Thrive in Hot and Dry Conditions

In Woodland or Partial Shade

In Fresh or Even Moist Soil

Other Varieties to Discover

Euphorbia characias - Spurge

Also known as Mediterranean Spurge, Euphorbia characias is a species native to the Mediterranean Basin, featuring blue-green evergreen foliage, a bushy habit, and spring flowering in green-yellow tones.

• Flowering time July to October
• Height at maturity 80 cm

See the product sheet

Euphorbia characias subsp. wulfenii - Spurge

This spurge is appreciated for its bright green-yellow flowering, blue-green foliage, and bushy silhouette, which is taller than the typical species.

• Flowering time April to July
• Height at maturity 90 cm

See the product sheet

Euphorbia characias Tasmanian Tiger - Spurge

The ‘Tasmanian Tiger’ spurge is remarkable for its blue-green foliage, widely variegated with cream white. It offers soft yellow and cream flowering in spring. It has been awarded the Award of Garden Merit by the Royal Horticultural Society (RHS).

• Flowering time May, June
• Height at maturity 80 cm

See the product sheet

Euphorbia myrsinites - Spurge

The Corsican spurge is distinguished by its prostrate stems, originating from the stump and spreading along the ground. The leaves are blue-green, pointed, and spirally arranged around the stem. It has been awarded the Award of Garden Merit by the Royal Horticultural Society (RHS). It is perfect for a rockery!

• Flowering time April to June
• Height at maturity 10 cm

See the product sheet

Euphorbia martinii Baby Charm - Spurge

This is a dwarf variety of Martin's spurge (Euphorbia martinii). It offers yellow-green flowers in spring. Its foliage is evergreen.

• Flowering time May to July
• Height at maturity 30 cm

See the product sheet

Euphorbia amygdaloides Purpurea - Spurge

This woodland spurge variety offers yellow flowering in spring, highlighted by beautiful dark, purple, evergreen foliage.

• Flowering time May to July
• Height at maturity 55 cm

See the product sheet

Euphorbia amygdaloïdes var. robbiae - Spurge

This spurge offers dark green foliage and spring flowering in a tangy green. It is a running spurge, which spreads through its rootstocks.

• Flowering time May, June
• Height at maturity 50 cm

See the product sheet

Euphorbia polychroma - Spurge

The polychrome spurge forms a beautiful, well-rounded, very wide clump. With its tangy, bright yellow-green flowering, it is ideal for bringing brightness to a slightly shaded spot in the garden!

• Flowering time May, June
• Height at maturity 40 cm

See the product sheet

Euphorbia dulcis Chameleon - Spurge

This spurge is appreciated for its purple foliage, which changes colour throughout the seasons! It forms a rounded clump.

• Flowering time June to August
• Height at maturity 40 cm

See the product sheet

Euphorbia palustris - Spurge

The marsh spurge is a perennial plant with an upright habit, featuring bright green-yellow flowering, and leaves that take on beautiful orange hues in autumn. It has been awarded the Award of Garden Merit by the Royal Horticultural Society (RHS).

• Flowering time May to July
• Height at maturity 1,50 m

See the product sheet

Euphorbia griffithii Fireglow - Spurge

This spurge offers a striking orange-red flowering. It prefers rather cool, but well-drained soils that are relatively rich in organic matter.

• Flowering time June, July
• Height at maturity 60 cm

See the product sheet

Euphorbia martinii Ascot Rainbow - Spurge

This variety, derived from the species Euphorbia martinii, is remarkable for its highly coloured foliage. The young leaves are red, and they later turn green, edged with cream yellow. It has been awarded the Award of Garden Merit by the Royal Horticultural Society (RHS).

• Flowering time May to July
• Height at maturity 60 cm

See the product sheet

Euphorbia lathyris - Spurge

This is the spurge known as mole's herb or Euphorbia lathyris. It is distinctive for its leaves arranged in a cross around the stem. It is a biennial plant that flowers in summer and is reputed to deter moles.

• Flowering time August, September
• Height at maturity 90 cm

See the product sheet

Euphorbia cyparissias - Spurge

The small-cypress spurge gets its name from its small linear leaves. It offers yellow-green flowering in spring. It is a prolific plant that eventually forms a vigorous ground cover. It is deciduous.

• Flowering time May to August
• Height at maturity 30 cm

See the product sheet

Planting euphorbias

Where to plant?

Most euphorbias thrive in full sun. Those with purple or reddish foliage take on more beautiful hues when exposed to direct sunlight. However, some species, such as Euphorbia amygdaloides or Euphorbia dulcis, are suited for planting in woodland areas, in shade or partial shade.

Euphorbias grow well in fairly ordinary soil. They do not like stagnant moisture and therefore prefer well-drained sites. Feel free to add gravel or coarse sand to facilitate water infiltration. However, Euphorbia palustris enjoys moist soils.

Euphorbias are quite content with poor soil. On the contrary, for most species, it is better to avoid soils rich in organic matter, with the exception of Euphorbia griffithii and Euphorbia polychroma, which prefer substrates rich in humus.

Some euphorbias adapt very well to pot cultivation, for example, to enhance a terrace or an indoor courtyard.

For rock garden cultivation, Euphorbia myrsinites is particularly suitable. For woodland areas, opt for Euphorbia amygdaloides, the wood euphorbia. Euphorbia palustris prefers cool, even moist, soils.

Reflecting their true diversity, euphorbias have different requirements depending on the species. Some prefer partial shade, others slightly cooler soils, and some are better suited for indoor cultivation… They generally appreciate well-drained, poor, and sunny sites, but there are often exceptions! It is best to choose their location carefully, as once established, euphorbias do not like to be moved.

When to plant?

Euphorbias are planted in autumn. This allows them to start settling in before winter and to flourish in spring. It is also possible to plant them in spring, starting from April. In any case, intervene outside of frost periods.

How to plant?

In the ground:

1. Dig a planting hole two to three times the size of the root ball. Add some coarse sand or gravel if necessary to improve drainage.
2. Remove the root ball from its pot and place it in the planting hole.
3. Replace the soil all around.
4. Gently firm it down with the palm of your hand.
5. Water generously.

In a pot:

1. Choose a large pot, preferably made of terracotta.
2. Place a layer of gravel, broken pot shards, or clay balls at the bottom to allow water to drain more easily.
3. Add a well-draining substrate (for example, potting soil and coarse sand) to the pot.
4. Place your euphorbia in the pot.
5. Replace the substrate all around.
6. Water.

→ Learn more about growing euphorbia in pots

Euphorbia griffithii ‘Dixter’ (photo Christopher)

Maintenance

Most euphorbias are relatively drought-resistant and are satisfied with infrequent watering. They fear excess moisture in winter. Just water during prolonged dry spells. However, the needs differ from one species to another. For example, euphorbias with light, fine foliage will require a bit more water than those with fleshy leaves, or than succulent species, the latter behaving like cacti by storing water in their tissues.

Euphorbias do not need fertiliser, as the majority of them grow quite well in poor soils. It is therefore also unnecessary to add compost, except for a few species like Euphorbia griffithii or Euphorbia polychroma, which thrive in humus-rich soils.

Some species with a running habit, such as Euphorbia amygdaloides ‘Robbiae’, may sometimes need to be contained to limit their spread. Similarly, if your euphorbias tend to self-seed, you can cut off the faded flowers to prevent the appearance of seeds.

Most garden euphorbias are relatively hardy and therefore do not need winter protection. If you are growing other species, particularly succulent euphorbias, you can bring them indoors for the winter to protect them from the cold.

You can weed and remove the spontaneous seedlings that appear at the base of your euphorbias. We also recommend installing a layer of mulch to limit weeding.

If you are growing them in pots, remember to repot your euphorbias from time to time (every one to two years), in spring.

Pruning:

For some euphorbias, such as Euphorbia characias, it is best to carry out pruning once flowering is finished. Cut back the stems that have flowered close to ground level.

For deciduous species like Euphorbia griffithii, you can tidy up the clumps at the end of winter to remove dead or dried parts.

Beware of latex: euphorbias contain a toxic, milky sap in their tissues that can irritate the skin. We recommend wearing gloves and not rubbing your eyes after handling the plant.

Diseases and Pests

Euphorbias can be affected by Botrytis. Also known as grey mould, this disease is caused by a fungus and typically appears due to excess moisture, often from overly heavy soil. A confined environment also promotes this disease. Similarly, in a substrate that is not well-draining, it is possible for the roots of the euphorbia to rot. Euphorbias, particularly Euphorbia cyparissias, can also be affected by rust. This fungal disease is identified by the appearance of rust-coloured spots on the foliage. You can treat it using a horsetail decoction.

Regarding pests and parasites, euphorbias can be attacked by aphids. They pierce the tissues and extract the sap from the plant, weakening it in the process. To get rid of them, we recommend spraying black soap on the foliage. Euphorbias grown indoors can sometimes be affected by whiteflies, or aleurodes. Finally, you may also notice mealybugs appearing on your plants, although this mainly concerns succulent euphorbias.

Multiplication

Sowing

Euphorbias (notably Euphorbia characias) tend to self-seed spontaneously. Annual species can be sown directly in situ, in open ground, while perennials are better sown in trays, under a frame. Sowing takes place in spring and is quite easy to achieve.

1. Take a tray or container and fill it with a light, poor potting mix, without fertiliser.
2. Water to ensure the substrate is well moist.
3. Sow the seeds by spreading them over the surface.
4. Cover them with a layer of sieved potting mix (no more than twice the size of the seeds).
5. Lightly press down.
6. Water gently.
7. Place your sowing under a cold frame, in a bright location but out of direct sunlight. The temperature should be between 18 and 22 °C.

The substrate should remain slightly moist until germination. You may optionally cover the tray with plastic film to prevent it from drying out.

Propagation by Cuttings

You can propagate euphorbias in spring, around April-May, or in late summer for Euphorbia characias (after flowering). Since euphorbias are very diverse, the following example is mainly suitable for Euphorbia characias and closely related species.

1. Prepare a pot, filling it with a draining substrate (a mix of potting soil and coarse sand).
2. Take a young shoot, preferably from the base of the plant. The stem should measure between 7 and 10 centimetres in length.
3. Place it in warm water to stop the flow of sap.
4. Remove the leaves at the base of the stem, leaving only those at the top.
5. Plant the stem in the substrate.
6. Place the pot in a bright location, out of direct sunlight, and keep the substrate slightly moist until the cutting begins to grow.

Division of Clumps

Perennial euphorbias can be multiplied by division. This operation can be carried out in autumn or late winter (March), for species such as Euphorbia characias or Euphorbia griffithii.

Start by digging up the stump using a fork. Separate the clumps by taking young shoots that have a few roots each time. Replant them in a new location, then water.

→ Learn more about the multiplication of euphorbias in our tutorial!

Association

Euphorbias can be integrated into a border with other perennials. Plant them alongside columbines, lady’s mantle, hardy geraniums, or polemoniums, and in the company of small bushes. We recommend favouring vibrant flowerings!

Some examples of associations with euphorbias! Euphorbia characias ssp. wulfenii, Erysimum ‘Bedder Scarlet’, Erysimum ‘Bedder Vulcan Brune’ / Euphorbia ‘Black Bird’ and double tulip ‘Britt’ / Euphorbia polychroma and tulip ‘West Point’ (photo Andrew Lawson – Garden Collection – Biosphoto)

Euphorbias are ideal for integrating into a Mediterranean-style garden! Choose species such as Euphorbia characias or Euphorbia myrsinites. You can pair them with succulents and aromatic plants. For example, plant them with thyme, lavender, phlox, Jerusalem sage, sedums… Create a Mediterranean rockery, a dry garden with a mineral focus, which will require very little maintenance!

You can also create a composition by placing euphorbias in a large terracotta pot, alongside succulents, cacti, sedums, or houseleeks…

Euphorbias with a wild appearance, such as Euphorbia amygdaloides or Euphorbia palustris, are perfect for integrating into a naturalistic border! Combine them with grasses, loosestrifes, flax, bellflowers, or burnets… Always in a very natural style, some euphorbias can also be integrated into a woodland garden. This is the case with Euphorbia polychroma, which is ideal for brightening up a shady corner. Plant it alongside ferns, hostas, brunneras, Solomon’s seals… Also enjoy the stunning blue flowers of bluebells (Hyacinthoides non-scripta)!

Euphorbias can be integrated into a naturalistic garden. An example of an association with Euphorbia schillingii, Achillea ‘Terracotta’, Cosmos atrosanguineus, and astrantias. / Cosmos atrosanguineus / Astrantia major ‘Rosea’ / Euphorbia schillingii

You can also choose to play with colours, for example by favouring shades that contrast with the green-yellow of euphorbias. Or by integrating plants with colourful foliage that complement the hues of the euphorbias… Don’t hesitate to take advantage of the wide range of colours offered by heucheras!

Euphorbias can also find their place in an exotic border. This is particularly true for Euphorbia characias, or Euphorbia griffithii, with their vibrant hues. They pair well with castor oil plants, phormiums, cordylines, agaves, or colocasias… Prefer exuberant foliage and warm-toned flowerings.

Did you know?

• A spurge to drive away moles?

Euphorbia lathyris, or Gopher Spurge, is reputed to repel moles. However, it does not scare them away when simply planted: to be effective, branches must be cut and inserted into the tunnels. The latex contained in the stems will irritate the moles’ snouts.

• Spurge or cactus?

Some spurges have had to adapt to the sun and drought by developing the same evolutionary strategies as cacti. Their tissues have swollen, and the stems have become succulent, allowing them to store water. Leaves have been replaced by thorns. This phenomenon is called form convergence. Cacti can be identified by the presence of areoles (small rounded growths) at the base of the thorns, while spurges do not have them. Spurges have a white latex that appears at the slightest wound, whereas cacti have a more transparent sap.