Rattlesnake master | The Morton Arboretum

Rattlesnake master is a native plant that looks a bit like it belongs in the desert with its yucca-like leaves and white thistle-like flowers. This is a summer to early fall perennial that looks fantastic individually or grouped in a native garden, prairie, or border garden with dry sandy soils and lots of sunlight. Rattlesnake master is durable and adaptable to most soil conditions, though it may need support if the soil is too fertile or if it is not receiving enough sunlight. This species is native to the Chicago region according to Swink and Wilhelm’s Plants of the Chicago Region, and current research.

Family (English) Parsley
Family (botanic) Apiaceae (formerly Umbelliferae)
Tree or plant type Perennial
Native locale Chicago area, Illinois, North America
Size range Large plant (more than 24 inches)
Light exposure Full sun (6 hrs direct light daily)
Hardiness zones Zone 3, Zone 4, Zone 5 (Northern Illinois), Zone 6 (City of Chicago), Zone 7, Zone 8, Zone 9
Soil preference Alkaline soil, Dry soil, Sandy soil, well-drained soil
Tolerances clay soil, Dry sites, Occasional drought
Season of interest early summer, midsummer, late summer, early fall
Flower color and fragrance Fragrant, White
Shape or form Irregular, Narrow, Upright
Growth rate Moderate
Wildlife Butterflies, Insect pollinators

Size and method of spreading:

Typically, rattlesnake master will be between 2 to 6 feet tall and 2 to 3 feet wide. Rattlesnake master can self-seed aggressively, but this can be reduced by removing seed heads. When growing from seed, rattlesnake master does best when sown in the fall or after a month-long period of conditioning (stratification). Clonal offsets can grow from the root system, and the plant can be divided in the spring or fall.

Native geographic location and habitat: (include C-value if appropriate)

Rattlesnake master is native to some of the lower Eastern United States into the Midwest. C- value: 9.

Attracts birds or pollinators:

Rattlesnake master is visited by butterflies, moths, short-tongued bees, long-tongued bees, wasps, flies, skippers, beetles, and plant bugs, primarily seeking nectar from the flowers. There is a rattlesnake master stem borer (Papaipema eryngii) that burrows into the stems and roots and depends on this perennial to complete its life cycle. The larva of the seed-eating moth (Coleotechnites eryngiella) also depends on the flowers of rattlesnake master.

Leaf description:

The leaves of rattlesnake master look a bit like the leaves of the yucca plant, with the spines along their edges (margins). They mostly occur at the base of the plant (basal leaves), but some small leaves may appear on the upper portions of the stems. The basal leaves can reach up to 2 ½ feet in length and are long and narrow (narrowly lanceolate) with veins that are parallel. Rattlesnake master leaves are known to be bluish-green or grayish-green in color.

Flower description:

The white flower heads of rattlesnake master look a bit like thistle flowers or little golf balls (compressed umbels). They let off a strong, honeylike scent that helps to attract pollinators. Each individual flower has five white petals with notched tips, a white divided pistil, and five white stamens with light brown anthers. The individual flowers and each flower head are surrounded by starlike spiny bracts of lanceolate leaves.

Fruit description:

Each flower produces two dry fruits that split at maturity (paired schizocarps) with wings that have teeth that point forward (serrate).

Plant care:

Rattlesnake master does not like soils that are poorly drained, and the plant will not do well in overly moist conditions. This is a perennial with a deep taproot, so it is hard to transplant but will be resistant to drought stress. The taproot produces clonal offsets, so they may need to be divided in the spring or fall. To reduce self-seeding, remove seed heads as they appear.

List of pests, diseases, and tolerances:

Rattlesnake master is mostly resistant to foliar disease and pests. Herbivores, such as deer and rabbits, tend to be discouraged by the spines on the leaves.