Marsh dewflower
(Murdannia keisak)
Biological Category
Plants
NY Legal Status
Prohibited
Species Type
Plants
DESCRIPTION
Marsh dewflower is a member the spiderwort family (Commelinaceae).
Marsh dewflower is an annual, emergent plant with weak, succulent stems and small, pink, fall-blooming three petaled flowers characteristic of the family.
Note: Research for these pages was generated from citations listed. References for specific statements available upon request.
Leaves: Leaves are alternately arranged, lance-shaped and up to three inches in length.
Flowers: Flowers are small, pale pink to pale purple to white, three petaled and bloom in the fall. Flowers can be arranged singly or in small clusters at the ends of stems or in the leaf axils.
Marsh dewflower was accidentally introduced to the United States in 1935 when rice plants from its native range were imported for cultivation. The species is now extant in at least 16 states.
Marsh dewflower favors freshwater habitats such as the edges of ponds, wetlands, and streams.
Marsh dewflower reproduces both sexually, via production of copious amounts of tiny seeds, and vegetatively, by rooting at lower stem nodes. Vectors include water, human activity and waterfowl
Marsh dewflower is an aggressive invader of marshes, wetlands, ponds and stream edges. Capable of traveling great distances via waterfowl, this species can establish new colonies from plant stem fragments and seeds. Dense aggregations of Marsh dewflower can shade out plants growing below it, thereby altering the diversity of the communities it invades. Furthermore, the thick vegetative mats formed by large infestations can reduce water flow and stabilize sediments, causing a cascade of environmental and ecological changes.
There is no biological control agent currently in use against this species.
Pulling / Digging Up: Not advisable. Fragmented stems are easily dispersed and resprout, forming new colonies. (9)
Mowing: Not applicable
Girdling: Not applicable
Prescribed Fire: No information available
Prescribed Grazing: Not applicable
Soil Tilling: Not applicable
Mulching: No information available
Solarization: No information available
Hot Foam Spray: Not applicable
The pesticide application rates and usage herein are recommendations based on research and interviews with land managers. When considering the use of pesticides, it is your responsibility to fully understand the laws, regulations and best practices required to apply pesticides in a responsible manner. At times, the pest you seek to treat may not be on a pesticide label, requiring a 2ee exemption from NYSDEC. Always thoroughly read the label of any pesticide and consult the NYSDEC or a licensed pesticide applicator with questions.
Foliar Spray: A wetland safe 2-3% solution of glyphosate is effective at managing populations of Marsh dewflower. Treatment should be performed prior to fruiting/seed set. Follow up treatment may be necessary in subsequent years.
Cut Stump: Not applicable
Basal Bark: Not applicable
Stem Injection: Not applicable
Pre-Emergent Spray: Not applicable
General management overview and recommendation: As with any other invasive infestation, large occurrences of Marsh dewflower are best managed via a combination of mechanical and chemical means. Small seedlings or outlying plants can be hand pulled but care must be taken to remove all plant material. Dense patches must be sprayed to attain good control. All managed infestations should be monitored to prevent reinvasion from nearby populations, or re-sprouting of vestige fragments. Any new occurrences can be sprayed.
Post-treatment monitoring: Any infestations managed by chemical means must be revisited in 2-3 weeks to check for treatment efficacy. Follow up spot treatments may be necessary for at least one year after initial treatment.
Any pulled for fragmented plant material must be bagged and disposed of in a landfill or thoroughly dried and composted.
New To Oklahoma: Murdannia Kesiak
Dunn, C. P. & R. R. Sharitz. 1991. Population structure, biomass allocation, and phenotypic plasticity in Murdannia keisak (Commelinaceae). American J. Botany. 78(12):1712-1723.
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