Myosoton aquaticum (Giant Chickweed)

Plant Info
Also known as:
Genus:Myosoton
Family:Caryophyllaceae (Pink)
Life cycle:perennial
Origin:Europe
Status:
  • Weedy
Habitat:part shade; moist soil, thickets, along shores
Bloom season:May - October
Plant height:6 to 24 inches
Wetland Indicator Status:GP: FAC MW: FACW NCNE: FAC
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: 5-petals

[photo of flowers] ½-inch white flowers arising from leaf axils and at the tips of branching stems. Flowers have 5 petals that are deeply divided so they look like 10. 10 white-tipped stamens surround a green ovary with 5 short, arching white styles at the top.

[photo of sepals and glandular hairs] The 5 green sepals are a little shorter than the petals, narrowly egg-shaped with a blunt tip. The sepals and flower stalks are covered with glandular hairs.

Leaves and stem: Leaf attachment: opposite Leaf type: simple

[photo of leaves] Leaves are egg to heart-shaped, up to 2½ inches long and 1 inch wide, toothless and often wavy around the edges. The lowest leaves are short-stalked but the upper leaves are stalkless or nearly so, and may clasp the stem. Attachment is opposite, with leaf pairs at right angles to the pair above and below. The upper leaves and stems are covered in glandular hairs, the lower more likely hairless. Stems are many branched and weak, typically sprawling on surrounding vegetation for support.

Fruit: Fruit type: capsule/pod

[photo of fruit] Fruit is an oval capsule about as long as or a little longer than the sepals. As fruit develops, the flower stalk nods with the capsule hanging down at the tip. When ripe, the capsule splits open at the tip releasing numerous round, rusty brown seeds.

Notes:

A common weed of disturbed soils.

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More photos

Photos by K. Chayka taken in Anoka, Chisago and Ramsey counties. Photos courtesy Peter M. Dziuk taken in Chisago County.

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Steven - Tamarack Nature Center, White Bear Township, Ramsey County,
on: 2012-06-11 22:00:15

I have photos of the flowers if there is any need.

Posted by: Tim - Woman Lake, near Longville, MN 56655
on: 2015-10-17 09:27:00

The Giant Chickweed is common around our lake cabin. It's attractive, and doesn't seem invasive. Yet.

Posted by: Bryan P - Oakdale
on: 2016-11-01 13:28:57

Chickweed can form dense colonies and smother new vegetation, as witnessed in the first growing seasons of several wetland restorations in the northern metro suburbs. But in other areas it has been observed as a few singular plants in a patch of diverse shoreline/wetland vegetation. Seems to proliferate with more disturbance.

Posted by: S. M. Smith - McGrath Mn, Aitkin County
on: 2022-10-02 20:16:05

Bottom land along the Snake River. October 2, 2022

Posted by: Bill Brown - Grant
on: 2022-11-01 09:46:53

Several years after buckthorn removal. Had ignored this but am now being overrun by it, especially in lower areas. Need control advice. Thanks!

Posted by: John - Houston County
on: 2023-09-03 20:59:04

Does Gaint Chickweed have the Mohawk Hairs that Common Chickweed has? From the Pics, It didn't look like it but I want to confirm. Could Myosoton aquaticum be the result of 2 genera crossing? Myosoton is a monotypic genus (As with many Monotypic genera being made after 2 genera cross) making me suspect it to be the case here. If so, do you know if Myosoton can Cross with Stellaria? Do you know where I can find out, or if you have any links to phylogenic trees I can look at it?

Posted by: K Chayka
on: 2023-09-04 09:54:01

John, as seen in some of the photos, the giant chickweed stem does not have a row of hairs, but it is sufficiently different from common chickweed (much larger in all respects, for one) that that should not be mistaken for each other. Regarding hybrids, Minnesota Wildflowers has no knowledge or expertise regarding most hybrids, including those you mentioned. Those questions are better posed to a horticulturist.

Posted by: John - Houston County
on: 2023-09-06 13:47:15

Do you know any Horticulturist or Plant Breeding Experts I can ask? Or anyone who specializes in Chickweed Taxonomy/Phylogenic Trees? So far, This Website has the most straight Forward Knowledge on Chickweed Differences I've found. So Thank You!

Posted by: K Chayka
on: 2023-09-07 08:18:14

John, sorry but we do not know anyone expert in this species.

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