White Sweet Clover

Melilotus albus

mel-il-LOW-tus  AL-bus

Synonyms of Melilotus albus (27) (Updated on 12-18-23 from Plants of the World Online): Medicago alba E.H.L.Krause (1901), Melilotus albus Desr. (1797)(nom. illeg.), Melilotus albus var. argutus (Rchb.) Rouy (1899), Melilotus albus var. macrocarpus Rupr. (1860), Melilotus albus f. prolifer Dore (1959), Melilotus angulatus Trautv. (1841), Melilotus arboreus Castagne ex Ser. (1825)(not validly publ.), Melilotus argutus Rchb. (1832), Melilotus giganteus Trautv. (1841)(not validly publ.), Melilotus kotschyi O.E.Schulz (1901), Melilotus leucanthus W.D.J.Koch ex DC. (1815), Melilotus melanospermus Besser ex Ser. (1825)(not validly publ.), Melilotus officinalis subsp. albus (Medik.) H.Ohashi & Tateishi (1984)(nom. illeg.), Melilotus officinalis var. albus Mérat (1812), Melilotus officinalis var. vulgaris (Willd.) Wahlenb. (1820), Melilotus rugulosus Trautv. (1841)(nom. illeg.), Melilotus strictus Trautv. (1841), Melilotus tenellus Wallr. (1840), Melilotus urbanii O.E.Schulz (1901), Melilotus vulgaris Willd. (1809), Melilotus vulgaris var. gigantea Gaudin (1829), Melilotus vulgaris var. minor Gaudin (1829), Sertula alba (Medik.) Kuntze (1891), Trifolium album (Medik.) Loisel. (1807)(nom. illeg.), Trifolium melilotus Georgi (1775)(nom. illeg.), Trifolium vulgare Gueldenst. ex Ledeb. (1843)(not validly publ.), Trigonella alba (Medik.) Coulot & Rabaute (2013)

Melilotus albus Medick. is the accepted scientific name for White Sweet Clover. It was named and described as such by Friedrich Kasimir Medikus in Vorlesungen der Churpfälzischen Physicalisch in 1787.

Some sites, including the USDA Plants Database, may say Melilotus albus is a synonym of Melilotus officinalis. Normally, Melilotus albus is the White Sweet Clover while Melilotus officinalis is the Yellow Sweet Clover. Plants of the World Online by Kew lists both species as accepted. You may also see the name Melilotus officinalis subsp. albus for the White Sweet Clover which POWO lists as a synonym of Melilotus albus.

The genus, Melilotus (L.) Mill., was named and described as such by Philip Miller in The Gardeners Dictionary in 1754. It was first listed as Trifolium sect. Melilotus by Carl von Linnaeus in the second volume of the first edition of Species Plantarum in 1753.

As of 12-18-23 when this page was last updated, Plants of the World Online by Kew lists 23 species in the Melilotus genus. It is a member of the plant family Fabaceae with 793 genera. Those numbers could change as updates are made on POWO.

The above distribution map for Melilotus albus from Plants of the World Online apparently hasn’t been updated for a while. Areas in green are where the species is native, purple where introduced, and orange where it is doubtful. POWO gets some of their maps for the United States and Canada from Flora of North America for families recognized on that site. When I wrote this page FNA had not yet included genera from the plant family Fabaceae. FNA will be coming out with the Fabaceae family very soon then the POWO maps will be up-to-date. We are all a work in progress.

The distribution map above for Melilotus officinalis is from the USDA Plants Database for the United States and Canada. The USDA lists Melilotus albus as a synonym of Melilotus officinalis but POWO lists both species as accepted. Melilotus albus is normally considered the White Sweet Clover while Melilotus officinalis is the Yellow Sweet Clover. I have no idea why the USDA doesn’t update… OH, I know why… The USDA gets its maps from BONAP (Biotia of North America Program), and they don’t have Melilotus albus.

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 new observations are made.

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

I have been back on the family farm in West-Central Missouri since 2013 and became more interested in wildflower ID. I had never noticed any White Sweet Clover on the farm until August 2 in 2019. I was walking along the fence in the front pasture and noticed a group of mostly dead stems with a few clusters of white flowers. I took photos and uploaded them on iNaturalist and found out they were Melilotus albus (White Sweet Clover). I was going to keep an eye on them in 2020 so I could get better photos of the plant stems and leaves but that didn’t happen. I became fairly busy and forgot all about them… Then 2021 came and went and I didn’t notice them at all. I have made a note to look for them in 2022 but I didn’t notice any.

Melilotus albus is a perennial plant that is found throughout North America. It is a native of Eurasia (and other areas) and was introduced to the United States in the 1600’s, 1700’s, or 1800’s, depending on what website you read. It was brought here as a forage crop and has spread rampantly, becoming very invasive in some areas. It has the ability to displace native species, especially those that grow shorter.

The species, like many clovers, will grow in just about any type of soil and climate. It has a deep taproot which allows it to be very drought-tolerant. It can grow to around 6’ tall, more or less, depending on soil fertility and climate. 

Besides making a great plant for honey production, the flowers attract many other insects which can also be a problem. In native habitats where the clover has become invasive, bees and other pollinators feed on the clover rather than helping to pollinate other wildflower species. 

Improperly cured hay that becomes moldy can be toxic to cattle due to the coumarin content in sweet clovers. The coumarin converts to an anticoagulant (dicoumarol) which can lead to internal hemorrhaging and death. Although the plants are somewhat bitter tasting, cattle can sometimes overeat even live plants which can cause similar issues.

The stems of Melilotus albus can be round or ridged and can be smooth (glabrous) or have a few short hairs (pubescent).

The trifoliate leaves grow in an alternate pattern along the stems. The leaves have three leaflets that are oblanceolate, obovate, oblong, oblong-ovate, oblong-elliptic… You get the picture. The leaves have quite a few teeth along the margins. The leaves have petioles (leaf stems) that are about an inch long, the center leaflet having another short stem (petiolule) of its own. There is also a pair of stipules emerging from the base of the petioles where they join the main stalk. 

Flowering stems emerge from the axis of the upper leaves which terminate in racemes of numerous white flowers.

The flowers have 5 petals (corollas) and are surrounded by a green calyx with 5 teeth. The petals, like other members of the plant family Fabaceae, consist of a standard, a keel, and two wings. With this species, the standard (may also be called a banner) is the larger upper petal that curves upward and is notched in the center. The keel is the boat-shaped petal on the opposite side of the standard, and the wings are the lateral petals on either side. The flowers have 10 stamens with 9 fused filaments and one filament that is basically free to the base. I need a very close-up photo of that…

The nectar of the flowers attracts many kinds of insects including long and short-tongued bees, wasps, butterflies, skippers, flies, beetles, and other plant bugs. It is considered an excellent nectar plant for Honey Bees. Various caterpillar species feed on the leaves buds, and flowers. 

Melilotus albus (White Sweet Clover) is similar to Melilotus officinalis (Yellow Sweet Clover) and have been considered the same species by some botanists. They often grow in the same location.

Hopefully, I will remember to keep an eye on the fence row in 2024 where I saw these plants growing in 2019. I need more photos!

I have enjoyed photographing and learning about the many wildflowers growing on the 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)
WORLD FLORA ONLINE (GENUS/SPECIES)
WIKIPEDIA (GENUS/SPECIES)
USDA PLANTS DATABASE
DAVE’S GARDEN
MISSOURI PLANTS
MISSOURI DEPARTMENT OF CONSERVATION
iNATURALIST
WILDFLOWER SEARCH
ILLINOIS WILDFLOWERS
MINNESOTA WILDFLOWERS
KANSAS WILDFLOWERS AND GRASSES
U.S. WILDFLOWERS
PFAF(PLANTS FOR A FUTURE)
GO BOTANY
FRIENDS OF THE WILDFLOWER GARDEN
UNIVERSITY OF WASHINGTON

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 even many thousands of species to keep up with. Accepted scientific names change periodically and it can be hard to keep with as well. 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. 🙂