With over 2000 species in the world euphorbias, commonly known a spurges make up the largest plant genus in the world. Most found in garden centres are native of cooler northern temperate and Mediterranean regions. As garden plants I find them invaluable in providing bold and interesting contrasting and complimentary architectural form when looked at in association with other garden plants whether in the border or a container.
Euphorbia’s are readily available in most garden centres and there is a euphorbia suitable for any garden situation, wet soil, dry soil, sheltered, exposed, sunny, shady etc. With the number in cultivation it is possible to have a euphorbia flowering in the garden throughout the year.
They are not troubled too greatly by pests and diseases and pruning is fairly straight forward. Although there are four pruning groups the ones mentioned below fall either into group 2, cutting the whole plant to ground level in the autumn after the foliage has died away or group 3 which is best done in the spring cutting back again to ground level previous year’s growth but leaving the already noticeable fresh growth untouched.
Most species provide colour from their stem leaves and the bracts surrounding their flowers, normally found at the top of the plant. Bracts are modified leaves around the reproductive part of the plant and not petals as found on most flowering plants. Within the bracts swollen nectar secreting glands attract insects such as bees and hoverflies to pollinate the plant. The colour and shape of the glands (and seeds formed after pollination) are used to identify some species and cultivars.
E. griffithii ‘Fireglow’ with Pulmonaria rubra ‘David ward’
Euphorbia griffithii (Group 2) is a very distinctive species with red-orange bracts at the top of current year’s growth. This is a deciduous species which produces early dark red stems before they leaf up providing added colour to the early spring garden. There are a few cultivars of this species. I have ‘Fireglow’ established in my garden and have recently acquired ‘Dixter‘. ‘Dixter‘ is said have darker stem leaves with more pinkish- grey undersides and more vermillion-red flowers although at this stage with my plant being quite young I cannot tell the difference with noticeable confidence as young growth in both forms is similar.
The plant sold to me as E.griffithii ‘Dixter’. I will soon visit a friend from Plant Heritage that has a confirmed one to compare.
This species is native to the eastern Himalayan region where it is found in moist soils so it does well in British gardens. It does have a tendency to spread by roots running below the soil and emerging a short distance from the plant but is shallow rooting and is easily dug up. During the growing season euphorbias produce a milky sap which can cause severe skin irritation so it is advisable to wear gloves if any cutting back is required and if the sap comes in contact with the skin to wash the area well.
I have E.myrsinites (Group 3) and E.characias ‘Blue Glacier’ (Group 3) contributing to container displays in my garden. E.myrsinites is a prostrate evergreen with blue grey leaves. It is short lived but seeds freely, it is best grown in gritty soil and I have separated the stem from the soil with a layer of grit to prevent the prostrate stems rotting when in contact with the soil.
E. polychroma (Group 2) the cushion spurge from central Europe is a low growing clump former to 60cm. Here I have it contrasting with an Acer palmatum. Geranium ‘Crystal Lake’ is planted nearby and waiting to take succeed E.polychroma when it finishes flowering in early June.
E.Redwing (Group 3) is another compact cultivar, semi evergreen in habit in my garden and long flowering.
E. amygdaloides ‘Purpurea’ (Group 3) This one can be a little temperamental, suffering from mildew but when it likes its location in a sunny well drained soil it’s purple foliage topped with lime yellow flowers can look really good.
E. stygiana is a new acquisition for my garden .This shrubby euphorbia in the wild is on the endangered list Distinctive features are dark green honey scented leaves with a white midrid. I have placed it amongst shrubs to protect it from cold and wind at the bottom of a path where I hope it will reward me with lovely scent as it matures. Being a shrubby euphorbia it belongs to group 4 and like most shrubs is pruned if necessary after flowering to keep in its desired location.
E. palustris ‘Walenburg’s Glorie’ (Group 2). A garden origin clump forming form of swamp spurge. This cultivar was initially bred in Scotland and grows around to 1.2m tall, not as tall growing as its Asian parent which needs staking. In autumn its foliage is said to grow from green to red although as yet I have not experienced this.