Hymenocallis occidentalis aka Northern Spiderlily

Hymenocallis occidentalis is a bulb plant in the amaryllis family. Its common names include woodland spider lily and northern spider lily. It comes from the central and southeastern United States. Kew places its native range in these temperate regions. NC State describes wild plants in moist fields, swamps, and bottomlands. It also notes the loss of wild plants from North Carolina.

This herbaceous perennial grows upright and forms clumps as its bulbs multiply. Garden plants reach 1.5–2.5 feet [0.46–0.76 metres] tall. They spread 1–2 feet [0.30–0.61 metres] wide. NC State also gives a shorter height estimate of 2 feet [0.61 metres]. Its growth rate is moderate. Glossy green leaves grow from the bulb at ground level. These long, strap-shaped leaves have smooth edges and no hairs. They can reach 2 feet [0.61 metres] long. The leaves die back in midsummer. Smooth, unbranched stems stand above the base.

The white flowers have a scent and a striking shape. Each bloom has a central cup and six long, narrow tepals. A thin white membrane links the bases of the anthers. The genus name refers to this membrane. Flowers measure about 0.5 feet [0.15 metres] across. Groups of five to ten form an umbel atop each stalk. NC State highlights summer flowers, while also listing spring and fall bloom. Green fruits follow the flowers. Each leathery capsule holds one to three fleshy seeds. The fruits measure less than 0.08 feet [0.025 metres] across.

Grow this spider lily in full sun or partial shade. It suits moist soil with good drainage and plenty of organic matter. It also tolerates wet ground and frequent standing water. Dry soil does not suit it. NC State lists acid, neutral, and alkaline soils as suitable. Its hardiness range covers USDA zones 5–8. The plant also tolerates heat and humidity. Gardeners can raise more plants by division or seed.

Use clumps beside ponds, streams, or water gardens. The plant also suits rain gardens, woodland settings, and borders. Group plantings show off its flowers and upright form. It can also grow in conservatories or indoor planted spaces. Remove yellow leaves to keep the planting neat. NC State reports no major disease or pest issues. Mealybugs, snails, and caterpillars can still cause damage. Its pest links also list slugs. The source flags this plant as poisonous to many animals. It names cats and dogs as animals at risk.