‘I love the evening primrose in my garden. But will it become invasive?’

The plant growing in your garden is most likely the large-flowered evening primrose, or Oenothera glazioviana, a striking, non-native, sun-loving, hardy biennial hybrid species that has a habit of popping up in newly established gardens unannounced, especially in coastal parts of the country where the soil is sandy/stony and free-draining. It flowers in its second year, producing 1.5m-2m tall, long-lasting spikes of acid yellow flowers from July to October that are loved by pollinating insects, especially moths and butterflies. Garden birds, especially finches, like to feed on the seeds in late summer and autumn. Evening primrose oil, which is extracted from the seeds, also has a long history of traditional use in the treatment of a variety of ailments from multiple sclerosis to PMT.