Wild Four O’Clock, Heartleaf Four O’Clock, Nightblooming Four O’Clock, Wild Umbrellawort

Mirabilis nyctaginea

mih-RAB-ih-liss  nyk-ta-JEE-nee-uh

Synonyms of Mirabilis nyctaginea (17) (Updated on 12-21-23 from Plants of the World Online): Allionia cucullata Fisch., C.A.Mey. & Avé-Lall., Allionia nyctaginea var. cervantesii Heimerl, Allionia nyctaginea Michx., Calymenia granulata Raf., Calymenia nyctaginea (Michx.) Nutt., Mirabilis nyctaginea var. alpicola Heimerl, Mirabilis nyctaginea var. conjungens Heimerl, Mirabilis nyctaginea var. eunyctaginea Heimerl, Mirabilis nyctaginea var. hirsuta Heimerl, Mirabilis nyctaginea var. pilosa Heimerl, Mirabilis nyctaginea var. setigera Heimerl, Mirabilis oxybaphus Bordz., Oxybaphus cervantesii var. grandifolius Choisy, Oxybaphus cervantesii var. minor Choisy, Oxybaphus cucullatus (Fisch., C.A.Mey. & Avé-Lall.) Choisy, Oxybaphus nyctagineus (Michx.) Sweet, Oxybaphus nyctagineus var. cervantesii A.Gray

Mirabilis nyctaginea (Michx.) MacMill. is the accepted scientific name for the Wild Four O’Clock. It was named and described as such by Conway MacMillan in The Metaspermae of the Minnesota Valley in 1892. It was first named Allionia nyctaginea by André Michaux in Flora Boreali-Americana in 1803.

The genus, Mirabilis L., was described by Carl von Linnaeus in the first volume of the first edition of Species Plantarum in 1753. Plants of the World Online lists the genus as Mirabilis Riv. ex L. indicating Augustus Quirinus Rivinus first named the genus. The International Plant Names Index (IPNI) has links to both Mirabilis L. and Mirabilis Riv. ex L. I checked the original publication and I didn’t see any reference to Mr. Rivinus… Most databases and websites just use Mirabilis L.

As of 12-21-23 when this page was last updated, Plants of the World Online lists 58 species in the Mirabilis genus. It is a member of the plant family Nyctaginaceae with 31 genera. Those numbers could change as updates are made by POWO.

The above distribution may for Mirabilis nyctaginea is from Plants of the World Online. Areas in green are where the species is native and purple where it has been introduced. The map on the USDA Plants Database is similar but doesn’t include a couple of states.

The map on iNaturalist shows where members have made observations. Anyone can join and it is a great website to confirm and share your observations. The maps on iNaturalist are continually updated as members post new observations.

THERE ARE SEVERAL LINKS AT THE BOTTOM OF THE PAGE FOR FURTHER READING AND TO HELP WITH A BETTER POSITIVE ID.

The first Mirabilis nyctaginea I found was on my farm on May 20 in 2017 (photo at the top of the page). I must have not been paying much attention because I thought it was a species of Milkweed. While it was right next to a Milkweed, the flowers were on an entirely different plant. When I uploaded photos on iNaturalist, I had it listed as an Asclepias purpurea. When a member pointed out it was a Mirabilis nyctaginea, whose common name is Wild Four O’Clock, I thought he was nuts! I took a closer look at the photo and noticed I had been mistaken and he was correct. I haven’t noticed any of these plants on my farm since I took the first photo. The rest of the photos on the page were taken on a friend’s farm in Benton County south of town in 2020.

Mirabilis nyctaginea is a perennial species that occurs throughout Missouri and can be found throughout North America. In some states, it is quite common and not so much in others. Several states report the species as invasive. The species gets its common name from its flowers that open in the late afternoon which stay open during the night. The flowers then wither and drop off the next morning.

Apparently, this species “prefers” poor soil with clay, sand, and gravelly material in areas where there is less competition. Illinois Wildflowers says they “will also grow in fertile loam, but suffers from the competition of neighboring plants.” That is likely why I haven’t seen any on my farm since 2017. 

This species likes growing in full sun but they will tolerate some shade. According to information online, habitats include upland prairies, streambanks, pastures fields, roadsides, railroads, disturbed areas abandoned fields, and of course, my friend’s grassless backyard… It grows there among the Perilla frutescens…

Upper stems terminate in clusters of 3-6 trumpet-shaped flowers that are subtended with 5-lobed, bell-shaped involucral bracts. The bracts enlarge at fruiting and can be hairless (glabrous) or sparsely hairy.

The flowers have no petals (corollas) but feature a pink to reddish-purple trumpet-shaped calyx with 5 notched lobes. Flowers have 1 pistil and 3-5 stamens with yellow anthers. Flowers can either have no scent or only slightly so. This flowering period is from May-October.

Mirabilis nyctaginea grows to 2-4’ tall from a thick taproot that can be fleshy or woody. The lower stem is somewhat 4-angled but the upper part is more rounded and can be smooth (glabrous) or slightly hairy (pubescent), or even slightly glaucous (with a whitish coating. Plants are dichotomously branching, meaning they fork into two equal branches. Plants can also grow multiple branches from the base.

The dark green leaves grow in an opposite manner along the stems and can grow up to 4” long x 3” wide. They are described as oblong-ovate to triangular-ovate in shape, have small petioles (leaf stalks), and normally have sharply pointed tips. The margins are smooth and may have a few very thin (cilia) or stiff (strigose) hairs.

The above photo shows how the stem forks into two equal branches.

The stems are somewhat 4-angled, appearing ribbed…

The rough grayish-brown to black seeds have 5 ribs and are hairy (pubescent).

Long and short-tongued bees and moths visit the flowers of Mirabilis nyctaginea for their nectar while short-tongued bees also collect the pollen. 

The Wikipedia article indicates a tea was made from the plant’s roots to treat fevers and expel parasites in traditional medicine. It has been used as a poultice to treat burns, sores, and swelling. Native Americans used the plant for coughs, sore mouth in infants, and to reduce abdominal swelling for women after giving birth. It also says there are references the species could be toxic… 

I have enjoyed photographing and learning about the many wildflowers growing on the family farm and in other areas. The farm is in Windsor, Missouri in Pettis County (Henry County is across the street, and Benton and Johnson aren’t far away). I have grown over 500 different plants and identified over 250 species of wildflowers (most have pages listed on the right side of the page). I am not an expert, botanist, or horticulturalist. I just like growing, photographing, and writing about my experience. I rely on several websites for ID and a few horticulturalists I contact if I cannot figure them out. Wildflowers can be somewhat variable from location to location, so sometimes it gets a bit confusing. If you see I have made an error, please let me know so I can correct what I have written.

I hope you found this page useful and be sure to check the links below for more information. They were written by experts and provide much more information. Some sites may not be up-to-date but they are always a work in progress. If you can, I would appreciate it if you would click on the “Like” below and leave a comment. It helps us bloggers stay motivated. You can also send an email to me at thebelmontrooster@yahoo.com. I would enjoy hearing from you especially if you notice something is a bit whacky.

FOR FURTHER READING:
PLANTS OF THE WORLD ONLINE (GENUS/SPECIES)
INTERNATIONAL PLANT NAMES INDEX (GENUS/SPECIES)
TROPICOS (GENUS/SPECIES)
FLORA OF MISSOURI (GENUS/SPECIES)
FLORA OF NORTH AMERICA (GENUS/SPECIES)
WORLD FLORA ONLINE (GENUS/SPECIES)
WIKIPEDIA (GENUS/SPECIES)
USDA PLANTS DATABASE
DAVE’S GARDEN
MISSOURI PLANTS
MSU-MIDWEST WEEDS AND WILDFLOWERS
MISSOURI DEPARTMENT OF CONSERVATION
iNATURALIST
WILDFLOWER SEARCH
ILLINOIS WILDFLOWERS
MINNESOTA WILDFLOWERS
KANSAS WILDFLOWERS AND GRASSES
PFAF(PLANTS FOR A FUTURE)
GO BOTANY
LADY BIRD JOHNSON WILDFLOWER CENTER
FRIENDS OF THE WILDFLOWER GARDEN
CONNECTICUT BOTANICAL SOCIETY
WASHINGTON STATE NOXIOUS WEED CONTROL BOARD
INVASIVE PLANT ATLAS

NOTE: The data (figures, maps, accepted names, etc.) may not match on these websites. It depends on when and how they make updates and when their sources make updates. Some websites have hundreds and thousands of species to keep up with. Accepted scientific names change periodically and can be hard to keep with. Some of the links may use a name that is a synonym on other sites. In my opinion, Plants of the World Online by Kew is one of the most reliable and up-to-date plant databases and they make updates regularly. I make updates “at least” once a year and when I write new pages or add new photos but I do get behind. We are all a work in progress. 🙂