Don't shut the door to your garden when the sun goes down. There are many plants that flower at night, adding color and texture under the moonlight. White flowers, in particular, seem to glow in the evening garden. In addition to the perennials below, also consider pots of white impatiens, the silver leaves of lamb's ear or lamium, and the annual groundcover sweet alyssum.
The evening primrose (Oenothera sp.) has fragrant flowers of pink, yellow or white that open in the evening. It requires full sun and well-drained soil with a neutral (7.0) pH.
Night Blooming Cereus
Night Blooming Cereus (Selenicereus sp.) has large, fragrant white flowers that open at night. It is a cactus, so it will not survive winters below 55 degrees F. However, you can grow cereus in a pot and bring it indoors for the winter.
Night Phlox or Phlox "Midnight Candy" (Zaluzianskya capensis) grows to 24 inches tall. It has white and maroon flowers that stay tightly closed during the day but open at dusk, releasing their fragrant honey and almond scent.
Moonflower (Ipomoea alba) is related to the morning glory. Its large, white flowers open at dusk and fill the garden with a strong perfume. It's a climber and will quickly cover a trellis or wall.
Despite their name, there are some daylilies that bloom at night. The "Moon Frolic" and "Toltec Sundial" cultivars both open after dusk.
Yucca (Yucca filamentosa) has flowers that are open throughout the day and night. But the blooms' soapy scent only is released in the evening.