Aquatic forget-me-not is an aquatic, rhizomatous, creeping perennial plant. Flowers are small, growing in an inflorescence and are blue with a bright yellow center.
OverviewOther names for this plant include:
- Common names: Forget-me-not, true forget-me-not, scorpion weed, love-me, marsh scorpion grass, mouse-ear scorpion grass, water forget-me-not and snake grass.
- Scientific names: Myosotis palustris.
- Aquatic forget-me-not can quickly crowd out native plant species and is able to form large monocultures, especially in situations where it is in or near a stream. This, in turn, affects community composition by reducing the number of native herbs.
- This species has the ability to escape water gardens and ponds and grow in undisturbed and natural environments. It can grow in wetlands, forests, bogs, swamps, marshes, lakes, streams and ponds.
- Aquatic forget-me-not is difficult to control due to its mechanisms for spreading. It is capable of abundant reproduction through spreading stolons (runners) and abundant seed production.
- Due to habitat competition, aquatic forget-me-not poses a threat to two threatened and endangered Wisconsin native plants; the threatened intermediate spike sedge (Eleolcharis intermedia) and the endangered winged monkeyflower (Mimulus alatus).
Classification in Wisconsin: Restricted
Species Assessment Groups (SAG) were assembled to recommend a legal classification for each species considered for NR 40. The recommendation for aquatic forget-me-not was based upon this literature review developed by the department.
Leaves: Alternate leaves that are stalkless. The upper leaf surface is either hairless or sparsely covered with hairs, while the lower surface is sparsely to moderately covered with hairs. Each leaf has a prominent central vein and is oblong to lance-shaped.
Flowers: Sky-blue in color with a yellow center. Flowers clustered in an inflorescence. Individual flowers are five-parted with the petals flat at the top of the tube. Sepals have flat, tight hairs. Blooms May-September.
Fruits & seeds: Smooth, shiny, blackish nutlets.
Stems: Angled and slightly hairy.
Similar species: A similar non-native species is the woodland forget-me-not (Myosotis sylvatica); however, the woodland forget-me-not can be distinguished by its spreading, hooked sepal hairs. There is a native forget-me-not that is somewhat rare in Wisconsin. Small forget-me-not (Myosotis laxa) can be distinguished from the non-native M. scorpoides by corolla limbs (the free part of petal), which are 2 to 5 mm wide in M. laxa and 5 to 10 mm wide in M. scorpoides. These species can also be distinguished by their calyx lobes, which are about as long as the rest of the floral tube in M. laxa and much shorter than the rest of the floral tube in M. scorpoides.
Mechanical: Smaller populations can be pulled or dug before seed set. It is important to remove the root system to prevent resprouting.
Chemical: There is little information available on the effectiveness of chemical treatment on Myosotis species. It is likely, based on effects on other similar vegetation, that dicamba or glyphosate would affect Myosotis spp. If treating in aquatic areas, a permit may be required.
View aquatic forget-me-not pictures in our photo gallery!
ResourcesSources for content:
- Czarapata, Elizabeth; Invasive Plants of the Upper Midwest: an illustrated guide to their identification and control. University of Wisconsin Press. 2005. Pg. 120-121.
- Invasive Plant Atlas of New England: factsheet