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Willow Lake - Sue Smith

Yavapai County Native & Naturalized Plants

Oenothera elata - Hooker's evening primrose

Synonyms: Oenothera hookeri
Other Common Names: western eveningprimrose
Plant Form: Forb

Family: Onagraceae

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Willow Lake
Sue Smith
Leaf attachment
Willow Lake
Sue Smith
Willow Lake
Sue Smith
Plant - summer
Willow Lake
Sue Smith
Plant - young
Willow Lake
Sue Smith
Forb Plant Description

Origin: Native   Life Cycle: Biennial or perennial
General Desc: A tall, erect, usually unbranched stem with large, showy, yellow flowers clustered along the stem. The plant forms a basal rosette of leaves the first year. It sends up a long leafy stem and blooms during the second year.
Identification notes: Stems tall up to 5 feet, often red. Leaf flat, not crinkled. Petals yellow, 1 to 2 inches long, open late afternoon, aging orange-red. Tubes below the petals are 1 to 2 inches long. Fruit cylindrical, not winged; seeds sharply angeled.
Height: To 5 feet


Habitat Description: Found along streams, in meadows, rocky slopes or scree, or in other disturbed habitats.
Plant Communities: Riparian, Disturbed Areas
Elevation: 3500 - 9000 feet

Flower Characteristics

Color: Yellow, orange-red     Shape: Regular in elongated clusters     Tubular: Y     Flowering Period: Jul - Oct
Description: Yellow flowers are up to 2 inches and consist of 4 broad, heart-shaped yellow petals; sepals up to 1/4 inch long, yellowish-green, red-striped or flushed. Flowers open in the late afternoon, becoming orange-red the following day, closing by noon.

Leaf and Stem Characteristics

Leaf Color: Dull green to grayish-green     Leaf Type: Simple     Leaf Shape: Narrow     Leaf Margin: Toothed     Leaf Attachment: Basal and alternate     Leaves Clasp: N
Hairs: Leaves and stems     Spines: N
Leaf Description: Dull to gray-green, white veined, lance-shaped, 1-1/2 to 9 inches long, up to 3/4 inch wide, narrower at the stem, margin toothed to almost smooth, sparse to dense stiff hairs. First year leaves form a rosette 4 to 16 inches long, to 1-1/2 inches wide.

Fruit and Seed Characteristics

Fruit Color: Tan   
Fruit Type: Capsule
Fruit Notes: Capsules 3/4 to 2-1/2 inches long, tapering upward, narrowly lance-shaped. They start out green turning to tan.
Seed Notes: Seeds are pitted, reddish-brown in 2 rows in each cell.

  Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr #C
Prescott, AZ 86305
(928) 445-6590
Version 8.0  
Last Updated: Feb 16, 2020  
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