Hardy Spurges

Table of Contents and IntroductionAfrican Violets: the Doyen of House PlantsAgapanthusAlstroemeriasAmerican SagebrushesAmerican WildflowersAndean Nymph - a pink mimulusAquilegias (Columbines)AuriculasAustralian AnnualsBellis Perennis (Daisies)Black-Eyed SusanBlue African LiliesBreeding DelphiniumsBreeding Fuchsias: Part 1: From SeedBreeding Fuchsias: Part 2: HybridisationBromeliads from SeedButterflies in Soy SauceCacti RaisingCampanulasChilean Bell FlowerChilly Treatment for Peruvian LiliesCollecting SeedConserving Annuals and BiennialsCosmosCucumbersCycads: Living FossilsCyclamen for IndoorsDahlias from SeedDamping OffErythroniumsF1 Hybrid - What Is it?F2 and Open Pollinated VarietiesFrom Obscurity to the Height of FashionGentiansGeraniumsGermination to Pricking OutGolden Impatiens - The StoryGrowing Alpines From Seed: Part 1Growing Alpines From Seed: Part 2Growing Bananas From SeedGrowing Cyclamen From SeedGrowing Eucalyptus From SeedGrowing Ferns from SporesGrowing Foxgloves From SeedGrowing Fritillarias From SeedGrowing From Seed: From Packet to SoilGrowing Hardy Ferns from SporesGrowing Hardy Geraniums From SeedGrowing Lewisias From SeedGrowing Magnolias From SeedGrowing Meconopsis From SeedGrowing Proteas and Related Genera from SeedHandling Small SeedsHardy Annuals: Part 1Hardy Annuals: Part 2Hardy CyclamenHardy SpurgesHelleboresIncreasing your Violas and ViolettasKeeping Records of Seed SowingLettuce - the Vital Part of any SaladLord Anson's PeaMagnolias - the Root of the ProblemMimulus from Seed to Seed in Sixty DaysNew Guinea ImpatiensOld-fashioned Sweet PeasOnions with EverythingPansies are not Difficult to Grow from SeedParsleyPerennials for American GardensPetuniasPhygelius - their cultivation and propagationPinks: Evocation of the PastPlants That Flower OncePrickly but NicePropagatorsRadishesRaising PalmsRaising PrimulasSalad Leaves - a lot to be desiredShow Stoppers Twice OverSowing SeedsSowing in Open GroundSowing to Feed our FriendsSturt's Desert PeaSweet Peas - Autumn SownSweet Peas - Sowing and GerminatingTall and HandsomeTechniques with Tiny SeedTexas BluebellThe Effect of Light on Germination and SeedlingsThe Nervous PeaThe Scarlet Welsh PoppyThe Search for the Yellow Sweet PeaToad LiliesTomatoesTreasure Hunt for TasteUnderstanding Latin NamesUnique Poppy (Mother of Pearl)Viability of VegetablesWeaning SeedlingsWill the Real Mimosa Please Stand Up

Anne Stephney selects a few of the best hardy euphorbias from this vast genus.

This diverse genus of some 2,000 species from temperate and subtropical zones, includes many herbaceous perennials, biennials, annuals, some sub-shrubs and even several succulents, some of the last mentioned plants capable of reaching tree-like proportions. Euphorbia pulcherrima, the popular Christmas pot plant better known as the Poinsettia is a member of this large family as, too, is the Crown of Thorns, E. milii (E. splendens), a small spiny semi-succulent greenhouse shrub often used as a windowsill plant, but it is with the hardy perennial forms that we are concerned here.

As decorative plants for the border these hardy spurges are of tremendous value to the gardener, many of them providing important, often evergreen, structural shape and form in foliage shades ranging from the icy blue-grey of E. myrsinites to the rich, deep carmine-purple of E. amygdaloides ruhra. When cut, their long vase life and unusual colour range puts the euphorbias high on the list of favourite plants for flower arrangers.

Rarely troubled by garden pests or disease, these easily cultivated plants are quite undemanding, growing in any fertile, well-drained soil and once established will provide long-lasting displays of both foliage and flower. Although the true flowers are in themselves quite small and insignificant, these are surrounded by most attractive petal-like bracts growing in terminal clusters. These are carried either in flat or domed heads, or in dense columnar panicles, depending on the species. Whilst most have a marked preference for a position in sun, some will tolerate shadier sites and one in particular, E. rohbiae, will positively thrive in deep dry shade. Toxic sap and poisonous seeds

Extreme skin irritation and a most unpleasant rash can be caused by the toxic white, milky sap which bleeds from cut or damaged stems and leaves of all this family and it is important therefore to avoid the sap coming into contact with the skin or eyes. Seed, too, is poisonous and should be kept out of reach of children.

Germinating seed

Many of these desirable plants can be grown quite simply from seed, one 5in (13cm) pot usually yielding enough seedlings for the gardener's own needs with some to spare for distribution amongst fellow enthusiasts.

Explosive seed capsules will scatter the ripe seed over a fairly wide area and the resulting self-sown seedlings, particularly of the more prolific varieties, can be a real nuisance. It is therefore advisable to keep a careful watch on the plants after they have flowered so that seed can be collected before it is dispersed, both to prevent self-sowing and to provide material for the gardener's own use.

Fill a 5in (13cm) crocked pot with a mixture of equal parts coarse sand and potting compost firming lightly to within about 3/8in (1cm) of the pot rim. Seed should be sown thinly on this surface, covered with a fine layer of sieved compost and topped with a layer of grit to the pot rim. This final layer will prevent the surface of the compost from compacting and help to conserve vital moisture. After watering, either by standing the pot in a tray of water or from above using a very fine rose, the pot may be placed in a cold frame and requires little further attention other than careful watering when necessary.

Potting on

Seedlings should be pricked out as soon as they can be handled without risk of damage to the stems and potted off individually to develop and grow on until large enough to be planted in their permanent position in the garden. By potting them singly, the possibility of disturbance to the roots, which they dislike, is avoided.

Pot-grown plants soon exhaust available nutrients in the growing medium and regular feeding is therefore helpful in promoting sturdy growth. When using proprietary brands of liquid fertiliser it is, however, important to strictly adhere to the manufacturer's instructions for use. Overfeeding will lead to the plants' growth becoming too vigorous in the early stages only to be severely checked when their final transplanting takes place.

Varieties

Native to North Africa and Europe to south-west Asia, the Wood Spurge, E. amygdaloides, adapts well to our climate growing to about 2ft (60cm) with erect stems and bright floral bracts in spring of yellow-green. Becoming increasingly popular, its darkest form E. amygdaloides rubra grows to only about 18in (45cm) high with stems in the same rich carmine-purple shade as the foliage tips. A surprising contrast is provided in spring when the whole plant is covered in the brightest vibrant lime-green floral bracts.

From the Mediterranean comes the sub-shrubby E. characias, an altogether larger architectural plant growing to well over 3ft (90cm) in height. Its subspecies, E.c. wulfenii is often seen in gardens; mature plants make imposing specimens with soft greyish-green foliage and dense trusses of yellowish-green floral bracts in columnar panicles up to 9in (23cm) long from May to July. Propagation of 'Lambrook Gold', a superior form of this latter plant selected by Margery Fish, must be carried out vegetatively in order to perpetuate the true variety.

On light soils E. cyparissias can be a real menace despite its graceful appearance. However, I found the heavy clay soil in my last garden kept it more in check and it is a useful and pretty plant for wild corners, with delicate grey feathery foliage reddening beautifully in the autumn.

Rich autumn colouring is also a feature of E. dulcis, a neat, pretty plant although perhaps a little nondescript during the earlier months.

Undoubtedly one of the best euphorbias, E. griffithi has brick-orange floral bracts, brighter in the form E. g. 'Fireglow', and best of all in its most superior form, E.g. 'Dixter' selected by Christopher Lloyd for its rich dark coloured floral bracts carried over erect 3ft (90cm) stems from late May.

A sunny position is vital to maintain the good foliage colouring of these forms. A wonderful companion for E.g. 'Dixter' is the shorter E. polychroma, flowering of which begins a little earlier and making a dense rounded mass of soft green foliage topped with chrome yellow bracts.

A favourite evergreen species is the very low growing E. myrsinites at only 8in (20cm) high. The sometimes 2ft (60cm) long stems are closely clad with icy blue-grey pointed foliage and look charming when planted so that they can scramble and trail over the edge of a low retaining wall. In spring the terminal clusters of chrome-yellow bracts last for several weeks before fading to pink. It does well in my chalky, dry soil and will seed itself around moderately enough to provide a few small plants to pot up and give away to gardening friends.

With similar glaucous foliage, the stems of E. rigida have an upright growth habit and growing no taller than about a foot (30cm) high, is a choice plant for the front of the border.

E. mellifera, the shrubby Honey Spurge much visited by nectar-seeking bees, comes from the Canary Islands where mature specimens will grow up to a height of 10ft (3m). Being a little tender it is unlikely to reach anywhere near these proportions in our English gardens, and will need to be planted in a warm sheltered spot with additional protection to see it through its first winter. Once established, however it makes a handsome shrub, with branching stems clothed in bright green, pale mid-ribbed leaves over which the dome-shaped umbels of unusual brown flowers are carried.

In dry shade E. robbiae is one of the few plants to thrive where most others soon perish, its glossy rosettes of dark green foliage making useful ground cover throughout the year. Shortly before flowering the stems have a fascinating habit of drooping their heads so that the stem looks like a shepherd's crook, straightening when the plant comes into bloom in June and July with 3in (7.5cm) wide heads of pale yellowish-green bracts.

Midsummer flowering E. seguierana is a slender 18in (45cm) tall tufted plant, but it is its subspecies E. s. niciciana that is well worth growing for its abundant lime-green bracts carried for three months over blue-grey foliage.

Sun and moisture retentive soil are necessary for E. sikkimensis from eastern Himalayas. Given these conditions it will produce red stems of light-veined foliage up to 4ft (120cm) tall and umbels of pale yellow bracts through July and August. In spring the new shoots and leaf veins are bright red.

Gardeners with a liking for weird-looking plants will certainly want to grow the Caper Spurge, E. lafhyrus, a monocarpic plant which looks quite bizarre in its first year with erect 3ft (90cm) stems and symmetrically arranged linear leaves of blue-grey. More branched and bushy in its second year, 2in (5cm) wide umbels of yellow bracts are produced during June and July and, unless cut down after flowering, will reproduce itself very freely from self-sown seedlings.

Further information

In addition to the species described, many other worthwhile spurges are becoming more widely available and enthusiasts seeking information on unusual and interesting varieties will find an excellent source of reference in 'A Review of Spurges for the Garden', by Roger Turner published in the December 1983 issue of The Plantsman.

Seed Sources

A limited variety of seed is available from most seedsmen but by far the widest selection is found in the seed lists produced by such specialist societies as The Hardy Plant Society whose members donate seed collected from their own plants for distribution amongst other members. The Alpine Garden Society and Royal Horticultural Society operate similar seed distribution schemes, as do some of the botanic gardens.