Weed of the Month – November 2014


(Oenothera stricta ssp. stricta)


(Photos: C. Schultz, Cape Jervis; opening and withered flowers; flowering plant; base leaves)

The evening primrose produces erect flowering spikes most of the year; the 10cm yellow flowers are tubular, with 4 petals and 8 stamens. As the name suggests, flowers open in the evening. They then redden and wither away the next day as the flower above them on the spike opens. Most of the leaves are at the base, but smaller ones spiral up the flower spike. Both sets of leaves have a pointed tip and wavy edges; however the base leaves are hairless while the leaves on the flower spikes have tiny hairs. The stems themselves are hairy too, and often woody but unbranched. Originally from South America but now naturalized in S.A., the evening primrose is classified as an environmental weed; that is, it invades native ecosystems and adversely affects the survival of indigenous flora and fauna.