
Scientific Name: Oenothera biennis
I have never planted Evening Primrose in my gardens, yet they show up faithfully every year. In fact, this was the first native species to make an appearance before I even got into growing native plants. That’s because the seeds remain viable in the soil for many years, waiting for a disturbance, and when I dug a small patch of earth to plant vegetables shortly after moving into my house, Evening Primrose popped up with their lovely lemony yellow flowers.
Evening Primrose has a very deep taproot, and being short-lived (a biennial), the decaying root helps to aerate and take nutrients deep into the soil profile. The only potential downside to them is that they are a favourite of Japanese Beetles. However, I use that to my advantage because the Evening Primrose brings the beetles to a single eye-level location where they’re easily picked off into a bucket of soapy water.
As usual, the Plant Description and In the Garden sections are courtesy of Shawn Booth from In Our Nature. The content of this article is excerpted from our book The Gardener’s Guide to Native Plants of the Southern Great Lakes Region (Firefly Books), available wherever you buy your books.
Family: Onagraceae (Evening Primrose Family)
Alternate Common Names: Bastard Evening Primrose, Common Evening-primrose, Evening Star, Fever Plant, Four-o’clock, German Rampion, Golden Candlestick, Hoary Evening Primrose, Hog Weed, King’s Cure-all, Night Primrose, Night Willow-herb, Sand Lily, Scabish, Scavey, Scurvish, Speckled John, Tree Primrose, Weedy Evening Primrose, Wild Beet, Wine-trap
Plant description: Evening Primrose has a two-year life-cycle. During the first year it produces a low rosette of basal leaves. During the second year, it sends up a light green to red central stems covered in white hairs. Lance-elliptic leaves are found in an alternate pattern along the stem and measure up to 20cm long and 5cm wide (they are usually smaller than this). They are hairless to finely hairy, toothless or with small teeth and borne on little to no leaf stalk. Stems terminate with spike-like clusters of many yellow flowers each about 5cm across. Each flower has 4 heart-shaped petals surrounding 8 yellow stamens and a cross-shaped stigma. Each flower appears to be borne on a long stalk but this is actually an elongated calyx tube (the part that bears the sepals and stamens). Four sepals are found behind each flower, measuring about 3cm long and bending backwards as the flower matures. As the flowers fade, they produce 3-4cm long, tubular seed pods that contain hundreds of tiny seeds.



In the Garden: Evening Primrose features a spire of vibrant, lemon-yellow flowers. These flowers open up in the evening and stay open until hit by the morning sun. They also stay open to brighten up cloudy days! A dependable choice for nutrient poor soils and the sturdy stems will persist into the winter months to extend interest.
Skill level: beginner to intermediate
Lifespan: biennial
Exposure: full sun to full shade
Soil Type: rocky, gravelly or sandy soils.
Moisture: dry to medium
Height: 90-150 cm (up to 210 cm in ideal conditions)
Spread: 30-90 cm
Bloom Period: Jun, Jul, Aug, Sep
Colour: yellow
Fragrant (Y/N): Y (lemon scent)
Showy Fruit (Y/N): N
Cut Flower (Y/N): Y
Pests: no serious insect or disease problems though leaf spot and powdery mildew may occur; this plant is a favourite of the invasive Japanese Beetle (Popillia japonica)
Natural Habitat: occurs throughout the region in disturbed areas, along roadsides, lakeshores and river valleys
Wildlife value: Moths are the main pollinators of the flowers, especially Sphinx Moths. The high oil-content seeds are eaten by goldfinches and other small birds. It is the host plant for a number of moths including the Primrose Moth (Schinia florida), Pearly Wood Nymph (Endryas unio) and White-Lined Sphinx (Hyles lineata).
Butterfly Larva Host Plant For: none
Moth Larva Host Plant For: Pearly Wood Nymph (Endryas unio), Grape Leaffolder Moth (Desmia funeralis), White-Lined Sphinx (Hyles lineata), Sparganothis Leafroller Moth (Sparganothis sulfureana), and Red-Streaked Momphid (Mompha eloisella)
USDA Hardiness Zone: 4-9
Propagation: the very small seeds need light to germinate (surface sow) but do not need to be stratified. Store in a cool, dry environment if spring sowing. Stem cuttings can be taken in spring.


Native Range:
