Synonyms: Eichhornia speciosa, Piaropus crassipes
Common Names: Common water hyacinth
Description: 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.
Habit: Free floating aquatic plant; 0.5-1 m (1.5-3 ft) tall; distinctive air bladders that keep leaves afloat; forms dense, floating mats.
Leaves: Thick, waxy, round, broad, 10-20 cm (4-8 in) in diameter, cuplike, glossy, green in color.
Stems: Spongy; erect; stems up to 50 cm (20 in) long; inflated with air bladders towards the base.
Flowers: 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.
Habitat: Native to the Amazon Basin. Found primarily in southern and western wetlands, marshes, ponds, lakes, and rivers.
Reproduction: By fragmentation of stolons, adventitious root system, and to a lesser extent by seed.
Similar species: 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: https://www.michigan.gov/egle/0,9429,7-135-3313_3681_3710---,00.html. 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.
Credits: 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.