Evening-primroses

Seedbox Common Water-purslane Pink Evening-primrose Narrow-leaved Evening-primrose

What are they?

Evening-primroses are common plants of prairies and open grasslands throughout much of North America. Several species are grown as agricultural crops for their essential oils.

Where are they found?

Many species are common in open, often dry, grassy places, even semi-arid sites such as sand dunes. Others more typically grow in wetland areas such as damp fields and the edges of swampy ground. Some species have spread due to cultivation and are most often found as adventives on waste ground and along roadsides.

Identification

The four petals, usually widely separated at the base, and the usually often rather large flowers make evening-primroses as a group fairly straight forward to recognize. The identification of some evening-primroses at the species level is also relatively straight forward, but others can be quite tricky, especially those that have escaped from cultivation and may be hybrids (which are not uncommon in this group). Critical attention to the hairs on stems and developing seed pods can sometimes be necessary.

American Enchanter's-nightshade Circaea canadensis

(Broad-leaved Enchanter's-nightshade) Local on leafy forest floors, usually forming colonies. Flowers June to August. Not officially recorded for Cape May County, but known from wet woodland at Higbee Beach WMA. This plant is placed here next to other, superficially similar-looking, members of the primrose family, though this plant is actually related to the evening-primroses and willowherbs.


Habit	Flower	Leaf	Seed capsule

Purple-leaved Willowherb Epilobium coloratum

Uncommon in wetlands and other damp areas. Flowers late July to early September. Flowers very pale pink, almost white, but darker in bud. In our area, the deeply-notched, pale petals on flowers carried on loose, open stems are distinctive.


Habit	Flower	Leaf	Seed pod

Common Water-purslane Ludwigia palustris

(Marsh Seed-box, Marsh Purslane) A common plant of wetlands and other swampy areas, though easily overlooked due to its small, petalless flowers. Flowers June to September. At first glance bears little resemblance to other members of its family due to the tiny flowers, carried in the axils of the opposite leaves. The flowers appear to have small, greenish petals but these are actually the sepals.


Habit on mud	Habit in water	Flowers	Leaves

Globe-fruited Primrose-willow Ludwigia sphaerocarpa

Local but often common where it occurs, in a seasonally flooded ponds and low, wet areas. Flowers July to September. When growing in standing water, the stems grow spongy growths around them and can become strangely disfigured.


Habit	Flower	Leaf	Stem

Seedbox Ludwigia alternifolia

Fairly common in wetlands and other swampy areas. Flowers late June to September. Flowers resemble those of the evening-primroses but the rest of the plant is quite different, with narrow, willowy leaves and thin, upright stems.


Habit	Flower	Sepals persist after flowering	Seed pod

Floating Primrose-willow Ludwigia peploides

A south-eastern species that has the capacity to become invasive in wetlands, where it grows out into open water from shallow margins. First recorded in Cape May County in 2012. Flowers August to October.


Habit	Flower	Leaves	Seed pod

Common Evening-primrose Oenothera biennis

Common and widespread in all sorts of open ground, fields and roadsides, especially in dry spoil. Flowers June to October.


Flower	Leaves	Seed pod	Close-up of seed pod

Oakes's Evening-primrose Oenothera oakesiana

Formerly considered a form of Common Evening-primrose and in New Jersey, currently only officially recorded from Cape May County. Several plants of this species flowered along the Main Trail at The Nature Conservancy's South Cape May Meadows in 2010. As this site received much disturbance and alteration in the years running up to this date, it is possible that this species was introduced to the site, perhaps on earth-moving equipment. Flowers June to October. In a local context, this species is relatively easy to identify as it superficially resembles Common Evening-primrose but has much smaller flowers. The leaves are slightly toothed and most of the plant bears silky white hairs.


Flower	Leaf with slightly wavy edges	Silky white hairs on stem	Seed pod

Seaside Evening-primrose Oenothera humifusa

Widespread and occasionally locally common on sandy beaches and dunes. Flowers July to September. Generally a low-growing species, with all parts thickly covered in silky hairs, giving it a pale, grayish look.


Habit	Flower	Young leaves in whorls	Whole plant covered in silvery hairs

Cut-leaved Evening-primrose Oenothera laciniata

Generally found growing as an adventive or weed of old fields, roadsides and waste ground and usually in dry soils. Flowers May to July.


Flower from above	Flower from side	Deeply cut leaves	Leaves on young plants often merely toothed

Narrow-leaved Evening-primrose Oenothera fruticosa

(Narrow-leaved Sundrops) A showy plant with startlingly yellow flowers, typically found in swampy ground. Flowers June to August.


Habit	Close-up of flower	Willow-like leaves

Pink Evening-primrose Oenothera speciosa

Native to the central prairies of North America, this pink-flowered, annual species is widely grown as a garden plant and occasionally can be found self-seeded in urban areas on roadsides and uncultivated plots. Flowers June to August.


Habit	Close-up of flower	Leaves lobed towards base

Lindheimer's Beeblossom Oenothera lindheimeri

Native to Texas and the Gulf States, this annual species is widely grown as a garden plant and occasionally can be found self-seeded in urban areas on roadsides and uncultivated plots. Flowers July to October. The asymetrical, four-petaled flowers, carried on long, slender stems are distinctive. Cultivated forms also come in pink.


Habit	Flower	Flower	Leaf

Cape May Plants An Identification Guide