Leafy spurge (Euphorbia esula) was introduced to North America as an ornamental plant and seed contaminant in the early 1800s. It spreads by resprouting from its extensive creeping root system, as well as by seed. Seasonal flooding of riparian infestations can move seed long distances downstream each year. The plant's sap contains a milky latex that causes skin irritation in humans and may poison livestock.
Stems are smooth and hairless and may grow to 1 m tall.
Leaves are attached directly to the stem and arranged alternately (and sometimes in spirals). They are smooth and waxy, and turn yellow or red-orange in fall.
Flowers and Fruit
Leafy spurge flowers are small and yellowish-green. They are supported by two heart-shaped, green bracts arranged in clusters. This is the primary visual determinant for leafy spurge. The plants seeds develop in pods on top of the bracts and when they are mature, the seed pods explode to distribute seed as far as 5m from the mother plant.
Like most invasive plants, leafy spurge can grow and thrive under a wide variety of soil types and conditions, both dry and wet. However, the plant does require warmth for good growth, making it a problem primarily in southern Alberta.
All parts of the plant contain a milky sap that causes skin irritations and may poison cattle and horses. This sap does not affect sheep and goats, which have been used to control infestations further south.
Since the toxic sap does not affect sheep and goats, these animals have been used to control infestations in pasture and riparian situations. Intensive grazing forces the plants to use their root reserves to re-sprout, weakening them and helping surrounding vegetation to compete. However, animal movement must be limited to prevent them moving seed to uninfested areas.
Hand-pulling and mowing are effective on small, young infestations. Always wear gloves and wash your hands when pulling leafy spurge to prevent skin rashes.
There are some herbicides registered for use on leafy spurge but they should be used in conjunction with seeding and fertilization to encourage competition from desirable vegetation. Please consult a local landscape company or garden center for recommendations.