: Eichhornia speciosa, Piaropus crassipes
: Common water hyacinth
: In its southern range, it doubles in size in two weeks. Considered to the be one of the most troublesome aquatic weeds in the world; seems persistent in the lower Detroit River/western Lake Erie, unclear if it is dying off in mild winters.
: Free floating aquatic plant; 0.5-1 m (1.5-3 ft) tall; distinctive air bladders that keep leaves afloat; forms dense, floating mats.
: Thick, waxy, round, broad, 10-20 cm (4-8 in) in diameter, cuplike, glossy, green in color.
: Spongy; erect; stems up to 50 cm (20 in) long; inflated with air bladders towards the base.
: Showy, lavender-blue in color, 6 petals, upper petals with a central, yellow blotch; 8-15 flowers occur on a single spike that can be up to 30 cm (1 ft) long; bloom mid-summer.
Fruit and seeds
: Seed pod, 3 celled, many tiny seeds.
: Native to the Amazon Basin. Found primarily in southern and western wetlands, marshes, ponds, lakes, and rivers.
: By fragmentation of stolons, adventitious root system, and to a lesser extent by seed.
: Pickerelweed (Pontederia cordata
) has purple flower spikes, lacks the conspicuous air bladder; not mat-forming.
Monitoring and rapid response
: Monitor ditches, ponds, wetlands, lakes and rivers along the lower Detroit River for this species. Most recognizable in bloom (late summer, early fall). Hand pull small populations; several herbicides are effective. Permits are usually required for herbicide use in water bodies and wetlands. For information see MDEQs Aquatic Nuisance Control website at: www.michigan.gov/deqinlandlakes. As this species is not widely distributed in Michigan, it is important to document new occurrences. Please obtain flowering or fruiting specimens and submit to: Anton Reznicek, Curator (Vascular Plants), University of Michigan Herbarium, 3600 Varsity Drive, Ann Arbor, MI 48108-2287.
: The Michigan Natural Features Inventory
(MNFI) has partnered with MISIN to provide the information in this fact sheet. Species images and/or information were used with permission from "A Field Identification Guide to Invasive Plants in Michigan's Natural Communities
" and "A Field Guide to Invasive Plants of Aquatic and Wetland Habitats for Michigan