Euphorbia

2 Mar

Euphorbia, 18 in. to 4 ft., small cup-shaped green flowers nearly all year, sun or shade, drought tolerant and deer resistant, spreads.

Euphorbia flower is technically a cyathium, consisting of fused bracts that form a cup around the much-reduced true flowers. Cyathia may appear singly or in clusters. In some cases, as with poinsettia (E. pulcherrima), additional bracts below provide most of the color. Fruit is usually a dry capsule that releases seeds explosively, shooting them up to several feet away. Many euphorbias are succulents; these often mimic cacti in appearance and are as diverse in form and size.

All euphorbias have milky white sap that is irritating on contact or toxic if ingested (degree of irritation or toxicity varies, depending on species). Before using cut flowers in arrangements, dip stems in boiling water or hold in a flame for a few seconds to prevent sap bleed. All need well-drained soil.

Euphorbia amygdaloides
From Europe and Turkey. Grows to 3 ft. tall, 1 ft.wide, with reddish green stems. Evergreen, 1–3-in.-long, dark green leaves have red undersides that turn darker red in winter. Greenish yellow flowers in clusters to 8 in. long at stem ends in midspring to early summer. Best in sun but tolerates some shade. ‘Purpurea’ has foliage heavily tinted purple.

Euphorbia amygdaloides robbiae
Grows to 1 ft. tall, 1 ft. wide and spreading, expanding its territory by rhizomes and sometimes becoming invasive. Reddish green stems. Evergreen, 1–3-in.-long, dark green leaves have red undersides that turn darker red in winter. Greenish yellow flowers in clusters stem ends in midspring to early summer. One of the more shade-tolerant euphorbias.

Euphorbia antisyphilitica
Native to southwestern U.S., Mexico. Erect plant to 3 ft. high, spreading by underground stems. Cylindrical pale green stems are covered with wax used commercially in making candles. Inflorescence consists of red bracts and white petal-like appendages in a star shape. Good for rock gardens, containers. Withstands light frosts.

Euphorbia characias
Mediterranean native. Upright stems crowded with narrow blue-green leaves form a dome-shaped bush 4 ft. high and wide. Chartreuse or lime green flowers in dense, round to cylindrical clusters appear in late winter, early spring. Color holds with only slight fading until seeds ripen; then stalks turn yellow and should be cut out at base, since new shoots have already made growth for next year’s flowers. Fairly drought resistant

Euphorbia characias wulfenii 

Euphorbia characias wulfenii
The most commonly grown form of this Mediterranean native. Upright stems crowded with narrow blue-green leaves form a dome-shaped bush 4 ft. high and wide. Broad clusters of yellow flowers held in dense, round to cylindrical clusters appear in late winter, early spring. Color holds with only slight fading until seeds ripen; then stalks turn yellow and should be cut out at base, since new shoots have already made growth for next year’s flowers.’Fairly drought resistant

Euphorbia cyparissias
European native forms feathery clump to 8 in. (possibly to 16 in.) high; spreads vigorously by rhizomes, often becoming invasive. Slender, erect stems branch toward tips. Crowded blue-green, needlelike leaves. Terminal clusters of yellow-green flowers appear in late spring to early summer; these may turn orange in poor soils. Plant may go dormant in winter.

Euphorbia milii
The climbing stems of this woody shrub grow 1 to 4 ft. tall, 1 1/2 ft. wide; bear pairs of red flower bracts nearly all year. Branches are covered with long, sharp thorns; evergreen leaves are roundish, thin, light green, 1 1/2 to 2 in. long, and usually found only near branch ends. Can be sheared as a low hedge, grown as a pot plant for indoor use, or trained against a fence or espalier.

Many varieties and hybrids varying in form, size, and bract color (yellow, orange, pink). Plants in the Supergrandiflora series are hybrids (often sold as varieties of E. x lomi) with large flowers in shades of yellow, pink, orange, and red; some are attractively speckled.

Euphorbia myrsinites
Native from southern Europe to central Asia. Grows to 6 in. high, 1–1 1/2 ft. wide. Evergreen plant with stems that trail outward from central crown, then rise toward tips. Stiff, roundish blue-gray leaves set closely in spirals around stems. Flattish clusters of chartreuse to yellow flowers top stem ends in late winter, early spring. Cut out old stems as they turn yellow. Withstands cold, heat, and aridity but is short lived in warm winter areas. Use in sunny rock garden with succulents and grayleafed plants.

Euphorbia palustris

From Europe, western Asia. Forms robust clump to 3 ft. high and wide, with many medium green, 2–3-in. leaves that turn yellow and orange in fall. Wide-branching clusters of yellow flowers in spring, early summer. Dies back in winter. Self-sows. One of the few euphorbias that will grow in damp or boggy conditions; also does well in ordinary garden soil, whether dry or moist.

Euphorbia polychroma 

Euphorbia polychroma 

Euphorbia polychroma
From Europe. Neatly rounded hemisphere to 1 1/2 ft. high, 2 ft. wide, with deep green leaves symmetrically arranged on closely set, hairy stems. From midspring to midsummer, plant is covered with rounded clusters of bright yellow flowers surrounded by whorls of yellow-green bracts. Effect is of a gold mound suffused with green. Displays good fall color (yellow to orange or red) before going dormant. Used in rock gardens, perennial borders. Short lived but reseeds.

a completely darkened closet each night for 14 hours; then, in the morning, move it into light for a maximum of 10 hours. Continue the process for 10 weeks.

Euphorbia seguieriana niciciana
Native from Balkans to Pakistan. Forms an airy, upright, fine-textured mound to 1 1/2 ft. high and wide, with narrow, inch-long blue-gray leaves and chartreuse inflorescences. Tolerates aridity.

Euphorbia x martinii

This is a hybrid between E. amygdaloides and E. characias. To 2–3 ft. tall and wide. Resembles a compact E. characias, with dense clusters of brown-centered chartreuse flowers in late winter, spring. Evergreen leaves are often tinged purple when young. Stems are red in winter.


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