Euphorbia amygdaloides ‘Purpurea’ makes for a good rock garden plant or edging plant. It also can work at the edge of a woodland garden, provided there is sufficient sunlight. Purple wood spurge blooms in the spring, in fact, that’s the time of year when all the magic happens for this plant: it’s also when it should be divided, or when its seeds should be planted. The growth of purple wood spurge can vary significantly, but the typical size at maturity is 12- to 36-inches tall, with a spread of about 1 foot. The stems are ringed by leaves, the beauty of which is the main reason gardeners choose to grow this perennial. The new foliage of purple wood spurge is lighter in spring (red to burgundy) than what follows. It is also lighter than any old leaves. The coloration after the initial leafing out becomes a deep purple-green. The stems start out red, although they lose this coloration in summer. Likewise, the leaves become progressively more green as summer advances. By August, the leaves are totally green and darker than the coloration on most green plants. The foliage becomes a very dark purple-green again in the fall. By November, there may be an interesting pinkish-red on the bottom leaves, while the rest of the leaves assume a purple color. If December is cold (in zones 4-5), the stems of wood spurge may start to droop over, and this deterioration eventually spreads to the leaves. In warmer areas (and during relatively warm winters in zone 5), much of the foliage should remain healthy and assume a black-purple color that is quite alluring.
Light
Grow this dark-leaved perennial in well-drained soil of average fertility, in full sun to partial shade. Full sun can improve the leaf color.
Soil
Purple wood spurge needs to be planted in well-draining, fertile soil.
Water
Water wood spurge weekly, and only when the soil is dry.
Temperature and Humidity
Purple wood spurge prefers dry weather and a Mediterranean-type climate. Humid summers will stress this plant.
Fertilizer
During the growing season, feed your purple wood spurge every two weeks with a 20-20-20 water-soluble fertilizer.
Purple Wood Spurge Varieties
Leatherleaf spurge (Euphorbia amygdaloides var. robbiae): works well as a spreading ground coverCushion spurge (Euphorbia polychroma): grows in a dome shape and is perfect for bordersMole plant (Euphorbia lathyris): features long, thin leaves, and greenish-yellow flowers
Pruning
Purple wood spurge is not especially amenable to pruning, nor is pruning usually necessary since it’s not a large plant. If you do prune it, don’t expect re-growth to occur quickly. Furthermore, the plant blooms on the previous year’s growth, so if you decide to prune (and if you value the flowers), wait until after the blooming period. Under some conditions, the plant may get leggy enough that you might want to prune it to restore compactness. Cleanup is a separate issue from pruning. For best appearance, cut off the flower stalks in June after they dry out and become less attractive. In spring, in cold climates, you also might remove damaged portions of stems that have succumbed to the winter cold. Purple wood spurge readily self-sows, so unless you want it to spread, you’ll probably have to pull new seedlings continually. Divide the plant in early spring to prevent overcrowding, if necessary.
Propagating Purple Wood Spurge
The easiest way to propagate purple wood spurge is by digging up the clumps of roots in the spring, dividing them, and replanting.
How to Grow Purple Wood Spurge From Seed
Purple wood spurge is super easy to grow from seed: Simply sow its seeds directly into the ground! Germination takes two to three weeks.
Potting and Repotting Purple Wood Spurge
Euphorbia amygdaloides ‘Purpurea’ does very well in containers, if planted in the right medium. To do so, buy large planters and fill them with a mixture of sand and regular potting soil. Wearing garden gloves, remove the seedling from its container—remember, purple wood spurge is toxic and can cause contact dermatitis. Place the seedling on the soil mix, and arrange it so its root ball is 1-inch below the rim of the pot. Fill with the soil mixture. Note: It’s best to have one purple wood spurge per pot. Water when the top feels dry.
Common Pests/Diseases
Purple wood spurge is a favorite for aphids, which you can treat with insecticidal soap. It also falls prey to grey mold, which can be treated by removing all infected areas with sterilized garden shears, avoiding watering in the evening, and treating your plants with a copper-soap fungicide.
