Species Native to Missouri
Common Name: snow on the mountain
Type: Annual
Family: Euphorbiaceae
Native Range: Temperate North America
Zone: 2 to 11
Height: 1.00 to 3.00 feet
Spread: 1.00 to 2.00 feet
Bloom Time: July to September
Bloom Description: Greenish-yellow subtended by showy white bracts
Sun: Full sun
Water: Dry to medium
Maintenance: Low
Suggested Use: Annual
Flower: Showy
Leaf: Colorful
Tolerate: Rabbit, Deer, Drought, Air Pollution
Culture
Annual that is easily grown in average, dry to medium moisture, well-drained soils in full sun. Plants are tolerant of poor soils, including rocky-sandy ones. Plants appreciate some part afternoon shade in hot summer climates. However, clumps tend to open up and lose their attractive shape in too much shade. Must have sharply-drained soils. Grow plants in the garden from seed. Seed may be started indoors 6-8 weeks before last spring frost date. Plants will remain in the garden from year to year by self-seeding. Plants have escaped gardens in many parts of the U.S. and may be considered invasive in some areas.
Noteworthy Characteristics
Euphorbia marginata, commonly called snow on the mountain, is a warm-weather annual that is native to prairies from Minnesota and the Dakotas to Colorado and Texas. In Missouri, it is native to the loess mounds in the far northwestern corner of the State (Steyermark). This is a single-stemmed plant that typically grows to 1-3' tall. It is usually unbranched below the inflorescence. Leaves (1-3" long) are medium green in spring, with the upper leaves gradually developing showy clean white margins. Compound cymes of inconspicuous greenish-yellow true flowers bloom at the stem ends from mid-summer to early fall. Although the true flowers (borne in cyathia) lack sepals or petals and are not showy, these flowers are subtended by long-lasting, petal-like white bracts (modified leaves) that are showy. Flower bracts and variegated upper leaves provide the ornamental show. Plant sap is a milky juice that is toxic if ingested.
Genus name probably honors Euphorbus, physician to the King of Mauretania.
Specific epithet is in reference to the white leaf margins.
Problems
No serious insect or disease problems. Aphids can be troublesome. Use gloves when working with this plant. Some gardeners experience skin rashes from contact with the toxic plant sap of euphorbias.
Uses
An excellent annual variegated foliage plant for borders, meadows and cutting gardens.