A few years ago my family visited Monticello in the summer. I was struck by how large Thomas Jefferson’s four o’clocks (Mirabilis jalapa) were compared to mine. I also liked the fact that it was a plant he grew and could still be grown today as an heirloom.
Although I had a few small plants in dry, lean soil in full sun, I was inspired to start new plants from seed. I planted them in very rich soil, in an area of the garden that received morning sun and afternoon shade. Yes, Virginia, despite our heat, humidity, and lack of rain, they are growing very well. They are about 2 feet tall with light green leaves and many yellow or pink blossoms.
The only trick is that the flowers do not open in the day. Although they are named for opening at 4:00 pm, mine never do. The tubular blossoms are sensitive to light and temperature and prefer to open during the cool of the evening, usually between 4 and 8 pm. They stay open all night long. Currently we are in the midst of a heat wave so they do not seem to be opening fully.
Flowers come in pink, white, red, yellow, magenta, or mixed, liked speckled. They are tender perennials which means they will grow as perennials in the south but in my zone 7 garden, they should grow as annuals. However I must be in a special micro-climate because mine come back every year. For people who are north of me, they can try to dig and save the tubers for next year, or start new seed next year. I have a friend who says they are considered aggressive in southern Virginia but I have not had any issues with mine.
Four o’clocks were cultivated and selected for various colors by the Aztecs prior to the Spanish Conquest. They were then introduced to Spain and England and were in cultivation in Europe for about 200 years before Linnaeus first described the species in 1753. Thomas Jefferson received his from France. In July 1767, he noted in his journal “Mirabilis just opened, very clever.”
Try these heirloom plants for an evening garden. The seed are very easy to save so you may see some at seed swaps but if not, try these seed companies.