Bonaparte's Crown

Euphorbia cyparissias (yoo-FOR-bee-ah sy-par-ISS-see-as)

Family: Euphorbiaceae Non-native Herbaceous (1-3 ft)

Cypress spurge is a herbaceous perennial herb with erect stems, narrow leaves, and fragrant chartreuse flowers. The mature plant resembles a small spruce or cypress tree. It grows about 12 inches tall, can spread rapidly, and tends to invade open disturbed areas in the United States. It is native to Europe to Northwest Turkey and was introduced in the United States as an ornamental in the mid 1860s. tt was planted in cemeteries and hence the common names, graveyard weed and graveyard ground pine. It is a member the spurge family (Euphorbiaceae). The specific epithet, cyparissias , means cypress-like and references the plant's foliage. Cypress spurge grows best in dry, well-drained soils in full sun. The plant tolerates poor soils, including rocky, sandy soils. It spreads by rhizomes and can be quite invasive, particularly in rich, moist soils, and freely reseeds. Eight to ten plants per square yard are sufficient to quickly form a dense ground cover. It tolerates drought and can often be found on dry banks and hillsides where little else will grow. The leaves are small, bright green, linear, and are alternate or whorled. The soft, needle-like foliage is much like a bottlebrush in appearance and the chartreuse flowers crowd together at the tips of the stems. The fruit is a 3-lobed capsule and contains 1 to 3 tiny gray seeds. Cypress spurge can produce large colonies. In the United States, cypress spurge is listed as a noxious weed in several midwestern states. It invades fields, pastures, farmlands, roadsides, and yards. It is potentially toxic to cattle and horses. It is considered invasive in the States of Connecticut, Massachusetts, New Jersey, New York, Rhode Island, and Wisconsin. Manual control is very difficult. Chemical control by use of herbicides such as glyphosate and has been effective but requires reapplications. Biocontrol by use of species of insects from Europe has been also successful in Rhode Island. Our native plants are at risk due to the loss of habitat by this aggressive plant. Instead of planting cypress spurge, consider native plants such Rudbeckia triloba (brown-eyed Susan), Coreopsis auriculata (mouse-eared tickseed), or Oenothera fruticosa (sundrops). Diseases, Insects, and Other Plant Problems: Cypress spurge is relatively pest and disease-free. It is a quickly spreading perennial that can overwhelm nearby perennials and native plants. Note that the milky latex sap that seeps from broken leaves and stems can be toxic to skin and eyes. Be sure to wear gloves and eye protection when handling this plant. All parts of this plant are toxic if ingested. Monitor small children and pets. VIDEO Created by Laura Barth for "Houseplants, Succulents, and Cacti," a plant identification course offered in partnership with Longwood Gardens. More information on Euphorbia .

Source: NC State Extension Gardener Plant Toolbox ↗ NC State Extension Gardener Plant Toolbox, 67 attributes.