Leafy spurge (Euphorbia esula) is a perennial that will grow to 91 cm tall. It is an aggressive, persistent plant with deep roots. It reproduces rapidly through its spreading roots and its abundant seed production. The flowers are yellowish-green clusters enclosed in yellow-green bracts. It produces a milky secretion that can irritate the skin and is poisonous to some animals.
I. Appearance and Characteristics
Euphorbia esula, commonly known as green spurge or leafy spurge, is a species of spurge native to central and southern Europe (north to England, the Netherlands, and Germany), and eastward through most of Asia north of the Himalaya to Korea and eastern Siberia. It can also be found in some parts of Alaska.
It is a herbaceous perennial plant growing to 1-1.2 m tall, with several stems branched from the base. The stems are smooth, hairless, or slightly hairy. The leaves are small, lanceolate, 4-8.5 cm long and up to 1 cm broad, with a slightly wavy margin. The flowers are small, produced in umbels with a basal pair of bright yellow-green petal-like bracts. Clusters of the bracts appear in late spring, while the actual flowers do not develop until early summer. All parts of the plant contain a toxic white milky sap.
It reproduces readily by seeds that have a high germination rate and may remain viable in the soil for at least eight years. The seed capsules open explosively, dispersing seed up to 5 m from the parent plant, and may be carried further by water and wildlife. Leafy spurge also spreads vegetatively from the root system, which is complex, reported to reach 8 m into the ground and 5 m across, and may have numerous buds.
There are two subspecies and a hybrid subspecies:
- Euphorbia esula subsp. esula. Leaves broadest near apex; umbel bracts 5–15 mm. Throughout the range of the species.
- Euphorbia esula subsp. tommasiniana (Bertol.) Kuzmanov (syn. E. waldsteinii (Sojak) A.R.Smith; E. virgata Waldst. & Kit.). Leaves broadest at the middle; umbel bracts 12–35 mm. Eastern Europe, western Asia.
- Euphorbia esula nothosubsp. pseudovirgata (Schur) Govaerts. Hybrid between the above two subspecies.
It has commonly been confused with Euphorbia virgata. E. esula is no longer considered a permanent component of the North American flora. E. esula is restricted to certain parts of Europe and not considered a weedy species, while E. virgata is found throughout the United States and Canada and has caused significant economic and ecological impacts.
E. virgata is best distinguished from E. esula by its leaves, which are 6-15 times longer than wide with margins that are (near-)parallel at the middle of the blade, while E. esula leaves are wider toward the tip, usually 3-8 times longer than wide, with margins that are not parallel at the middle of the leaf.
In addition, the apex of E. virgata is usually acute and the base is truncate to attenuate, while the apex of E. esula is rounded or subacute and the base is more gradually attenuate or cuneate. Mentions of E. esula in the North American flora and invasive species literature are now referred to as E. virgata.
II. How to Grow and Care
Leafy spurge (Euphorbia esula) is a perennial that will grow to 91 cm tall. It is an aggressive, persistent plant with deep roots. It reproduces rapidly through its spreading roots and its abundant seed production. The flowers are yellowish-green clusters enclosed in yellow-green bracts. It produces a milky secretion that can irritate the skin and is poisonous to some animals.
Sunlight
Leafy spurge thrives in full sun, requiring bright, unfiltered light to reach its growth potential. Despite this ideal, leafy spurge exhibits a high degree of adaptability, tolerating conditions of partial sun to full shade. However, suboptimal light exposure could impede vigorous growth and reduce the plant’s robust health. Noteworthy is leafy spurge’s ability to adapt to varied light scenarios, adjusting leaf orientation to maximize light absorption. It is best cultivated outdoors, positioned in sites that receive ample daily sunlight, which underscores its ecological role in open fields and prairies.
Temperature
Genus Euphorbia is very large and diverse, so its different species can be found in various habitats, but the majority are well-adapted to a temperature range of -29 to 4 ℃. Many spurges, in spite of having succulent leaves, cannot handle long periods without moisture and need to be watered weekly during hot summer days. Some cactus-like species are well adapted to high temperatures and prolonged dry periods, but most species used for landscaping and decorative gardening require more moisture for proper development.
Watering
Thriving in its native habitat’s variable moisture conditions, leafy spurge exhibits a notable drought tolerance. This species maintains a balance, preferring occasional hydration to mimic the irregular rainfall of its environment. Accordingly, it requires watering every week to sustain its vigor. In an indoor setting, leafy spurge is typically more prevalent and benefits from consistent ambient humidity to complement its watering schedule. As a herbaceous perennial, leafy spurge’s water needs are particularly crucial during its active growing season to support robust growth and resilience.
Soil
Spurges aren’t picky when it comes to soil type. They can grow in a variety of soils. Some species of Euphorbia can even thrive in nutrient-poor soils, requiring only that the soil be well drained. If the soil is full of moisture and is prone to water retention, it will most likely cause root rot.
Fertilizing
Leafy spurge doesn’t require large amounts of fertilizer for normal growth and development. In fact, very little fertilizer is required. As mentioned earlier, some species can thrive even in very poor soils, as long as those soils are well drained. Fertilizer should only be applied when the plants start showing nutrient deficiency symptoms on lower leaves. When the lower leaves turn yellow, it is time to add half-strength liquid fertilizer to the soil. That will keep the plant well fed for several months.
Planting Instructions
Dig a hole twice as wide as the plant’s root ball before planting. Then, turn the container with leafy spurge upside down and let the plant slowly fall into your hands. Place the plant upright in the hole and slowly fill in around the roots with loose and fertile potting mixture, adjusting the planting depth until it is just right. Water it once. Do not overwater, as standing water is not good for the plant.
Propagation
Leafy spurge’s ideal propagation season is spring and autumn, mainly through division. It has a moderate propagation difficulty. Successful propagation is indicated by new growth emerging from divided sections. Providing optimal soil moisture is a crucial tip for success.
Transplanting
For leafy spurge, the zenith of growth occurs from late spring to mid-summer, making it the ideal time to transplant. Choose a sunny spot with well-drained soil. Gently rehome your plant, ensuring minimal root disturbance for seamless acclimatization.
Repotting
Repot leafy spurge every 2-3 years in early spring, as it’s a vigorous perennial that can grow quite large. Choose a pot just a size bigger to encourage manageable growth and prevent stress. Ensure the new pot has ample drainage to accommodate its bushy form. Post-repotting, provide bright light and avoid overwatering to ensure leafy spurge recovers swiftly and thrives.
III. Uses and Benefits
Euphorbia esula has nutrient value similar to alfalfa (Medicago sativa L.) and crested wheatgrass (Agropyron cristatum (L.) Gaertn.) and provides nutritious forage for sheep and goats. Leafy spurge is used by beekeepers as an early-season food source to maintain honeybee (Apis spp.) colonies in early spring, but the honey is bitter and not sold for human consumption.