One of my favorite plants has begun to flower and always heralds the return of summer; these are the evening primroses, better known as oenothera. There are 124 species of annual, biennial and perennial oenothera and not all open just at night. A few species, commonly known as sundrops, remain open during the day. Two examples are O. perennis and O. fruticosa. These are exceptions to the rule as most greet you with large open flowers in the late evening hours, closing by mid-morning. They do so for many weeks, often months.

The flowers on evening primrose open over a period that extends from 4 to 10 pm. Most open so slowly that we aren't patient enough to sit through the process. Although there is one exceptional plant that pops open as you watch, which has prompted people to set up lawn chairs and gather around for the show. This particular evening primrose is Oenothera glazoviana, named after Auguste Francois Marie Glaziou (1828-1906). Possibly a cross between O. grandiflora and elata, the flowers quiver and shake before unfurling. Lemon scented, moths arrive to pollinate, which just adds to the show. This species is a biennial, growing a low rosette the first year, flowering the second year and dropping seed to begin the process again.

Oenothera odorata's petals are a soft peach, like old parchment. Very fragrant, which is implied by the botanical name, each flower opens for only one day but is followed by others, this ensures a fresh show every morning. The largest flowering species is Oenothera macrocarpa, (previously known as O. missouriensis), with large yellow flowers that appear on a plant that grows low to the ground. The species name, macrocarpa, refers to the seed pod, simply stating that it's a large carpa or seed pod (shaped like a star fruit).

This genus is native to North and South America with an old favorite originating in a field outside of Middleburg, VA. Back in the days that I still had Windy Hill Plant Farm, Polly Rowley (a frequent customer) brought me a wonderful small plant of an unknown oenothera she had taken notice of. Flowering for an extended time, open all day, the small yellow flowers were produced on a plant that stayed low, produced a lovely bushy mound and grew through heat and drought. She wanted it named 'Cold Crick', after her farm and we set about propagating it to sell. I know we sold at least 500 plants a year, it was a huge hit and happily now, I see that it's gone mainstream. Touted as sterile, we were never able to confirm a species and assumed it to be O. perennis. I feel hugely proud of this plant and so happy to see it's popular all over the country. Discovered right here in Loudoun County, thank you Polly!