Myriophyllum spicatum

Common Name: Eurasian water milfoil

Family: Haloragaceae

Common Synonyms: none

USDA Hardiness Zone: 6a-10b

Growth Habit: Aquatic submersed herb

Origin: Eurasia and Africa

FISC Category: 2

FDACS Listed Noxious Weed: Yes

Introduction Date: 1940s

IFAS Assessment:

• North: PROHIBITED
• Central: PROHIBITED
• South: PROHIBITED

Description

Perennial, floating or rooted, submersed aquatic herb with many-branched, slender, reddish stems to 3 m long or longer, often forming dense mats just below the surface of the water. Rhizomatous, rooting at the nodes and reproducing vegetatively by fragmented stems. Submersed leaves gray green, in whorls of 3 or 4, divided into 14-20 pairs of thread-like segments, appearing feathery. Emergent leaves reduced to tiny bracts subtending the inflorescences. Flowers tiny, solitary, in leaf axils of reduced leaf whorls on erect, emergent, spikes to 20 cm tall. Male flowers in upper leaf whorls, female flowers in lower whorls, bisexual flowers often occur in the middle of the spike. Bisexual and male flowers reddish. Fruit a tiny, 4-lobed, rounded capsule to 3 mm across.

Habitat

Lakes, streams, brackish water

Comments

Spreads and reproduces mainly by regrowth of plant fragments. Similar to nonnative M. aquaticum, and to the native Myriophyllum species.

Control Methods

• Manual: Mechanical: Water level manipulation (drawdown) has been used effectively to control Eurasian water-milfoil in Tennessee reservoirs (IFAS)
• Chemical: "Registered aquatic herbicides such as endothall, 2,4-D and fluridone provide temporary control of Eurasian water-milfoil, but efforts to eradicate the plant ""are rarely, if ever, likely to succeed"" (IFAS)"
• Biological: Insects have been used to help keep Eurasian water-milfoil under control, fish also have been successfully used (IFAS)

Control Notes

NA

References

Dave's Garden. 2014. PlantFiles: Eurasian water milfoil. http://davesgarden.com/guides/pf/go/32101/. Accessed on June 23, 2014.

IFAS, Center for Aquatic and Invasive Plants. 2014. Eurasian water-milfoil. http://plants.ifas.ufl.edu/node/278. Accessed on June 26, 2014.

Langeland, K.A., H.M. Cherry, C.M. McCormick, K.C. Burks. 2008. Identification and Biology of Non-Native Plants in Florida's Natural Areas-Second Edition. IFAS Publication SP 257. University of Florida, Gainesville, Florida.

Langeland, K.A., J.A. Ferrell, B. Sellers, G.E. MacDonald, and R.K. Stocker. 2011. Integrated management of non-native plants in natural areas of Florida. EDIS publication SP 242. University of Florida, Gainesville, Florida.