Star of Bethlehem (Ornithogalum spp)

plants, terrestrial, tier 2, tier 4

Names: Nodding star of Bethlehem (O. nutans), Common star of Bethlehem (O. umbellatum.)
Family: Asparagaceae
Life Form: Bulbous perennial forb

History & Introduction

These white flowered perennials have been introduced to North America from Europe and southwest Asia via horticultural plantings. O. umbellatum is more common than O. nutans, which might be under-reported, or mis-identified.

Reporting these species accurately to iNaturalist and iMapInvasives can help us better understand their spread within our region

Identification

Phenology: Both species flower April-May. Seeds ripen June-July.

Common star of Bethlehem
(O. umbellatum)

Tier: 4 (more common)

Leaves – Narrow 2mm-6mm

Flowers – In a corymb, spreading. Flowers usually point upward. Petals are often bright white in color. Anthers yellow – off white

Nodding star of Bethlehem
(O. nutans)

Tier: 2 (less common)

Leaves – Wider than O. umbellatum, 8-15mm

Flowers – In a raceme, often “nodding” downward, pale greenish color in the middle of petals, edges of petals more white. Anthers white.

Habitat

Both species have been found invading forest understories, roadsides, streambanks, meadows, lawns, and fields. Especially favors moisture in early spring. Goes dormant later in the growing season.

Damage

Emerging early in the spring, these plants spread via division of bulbs into bulblets which can lead to large monospecific patches which can crowd out early emerging native vegetation and spring ephemerals.

These plants have been described as toxic to humans and animals. This means herbivores such as deer likely avoid Ornithogalum spp, causing them to opt for native spring ephemerals- many of which are already found in low numbers in the wild within LIISMA due to habitat fragmentation and loss.

Prevention

Avoid planting Ornithogalum spp. Opt for native plants and encourage the growth of native vegetation on your property.

Control

Due to Star of Bethlehem’s narrow window of growth and extensive vegetative reproduction, control can be difficult.

Chemical control: Herbicides are not advised as they are monocots and most broad spectrum herbicides target broadleaf weeds. As well they have a waxy outer coating on their leaves that will reduce herbicide absorption.

Manual control: Avoid hoeing or tilling, as this will result in breaking up and spreading of bulblets. In small patches, digging up and removing as many of the bulblets over a number of years is the most effective way to reduce the extent and vigor of these perennials. Remove plants as soon as they emerge early in the spring. In larger patches where digging may not be possible, mowing after flowering but before seed set may help to reduce spread via seed, but will not outright kill it.

Cultural control: Competitive native plantings that can shade out this plant may help reduce its vigor and spread.