Common Name: rattlesnake master
Type: Herbaceous perennial
Family: Apiaceae
Zone: 3 to 8
Height: 2.00 to 4.50 feet
Spread: 2.00 to 2.50 feet
Bloom Time: June to September
Bloom Description: Creamy white
Sun: Full sun
Water: Dry to medium
Maintenance: Low
Flower: Showy
Attracts: Butterflies
Other: Winter Interest
Tolerate: Drought, Erosion, Clay Soil, Dry Soil, Shallow-Rocky Soil
Culture
Easily grown in average, dry to medium, well-drained soils in full sun. Prefers dryish, sandy soils. Self-seeds in optimum growing conditions. Plants tend to open up and sprawl if grown in overly fertile soils or in anything less than full sun. This is a taprooted plant which transplants poorly and is best left undisturbed once established.
Noteworthy Characteristics
Eryngium yuccifolium, commonly called rattlesnake-master or button snake-root, is a Missouri native plant which occurs in rocky woods, prairies and glades throughout the State and was a common plant of the tallgrass prairie. Most members of the parsley/carrot family (Apiaceae) have finely cut foliage and flowers in domed umbels. Not so with rattlesnake-master which features basal rosettes of parallel-veined, bristly-edged, sword-shaped, medium green leaves (to 3' long) resembling those of yucca (lily family) and tiny, stemless, greenish-white flowers tightly packed into globular, 1" diameter heads resembling thistles (composite family). Flower heads appear in branched clusters at the top of smooth stiff stems typically rising to 3-4' (less frequently to 5-6') tall from the centers of the rosettes. Flower heads are subtended by whitish, pointed bracts. The blooms are attractive to butterflies and other insect pollinators.
Genus name comes from an ancient Greek name used by Theophrastus for a plant which grew in Greece (probably Eryngium campestre) or is a Greek reference to the prickly or spiny nature of plants in this genus.
Specific epithet is in reference to leaves that look like Yucca.
Common name is in reference to a former use of this plant as a treatment for rattlesnake bite.
'Kershaw Blue' features basal clumps of striking, wide, glaucous-blue foliage. Mature clumps can reach around 2' tall and spread to fill a 2.5' area. Upright, 4.5' tall flowering stalks emerge in early summer bearing globular heads of tiny, creamy white flowers through to fall. This cultivar was named after Kershaw County, South Carolina where it was discovered along a roadside.
Problems
No serious insect or disease problems. Taller plants may need support, however staking of these substantial plants in a cosmetically acceptable manner can be difficult. Massing plants in naturalized areas where they can provide some support to each other may be the best solution for this problem.
Uses
Native plant gardens, rock gardens, naturalized areas or prairies. Also can be effective in borders.