Mouse-Eared Chickweed

Pink (Caryophyllaceae family):

Cerastium fontanum Baumg.

EPPO code:

CERVU

Other names:

Mouse ear chickweed, large mouse ear chickweed, mouse-ear

Species information

Lifecycle:

Annual, but more commonly perennial.

Propagation:

Mouse-eared chickweed reproduces by seed and by horizontal stems that root at the nodes forming dense patches.

Emergence:

Seed will germinate throughout the season; established plants will remain dormant over the winter, but will resume growth at relatively cool temperatures.

Habitat:

Mouse-eared chickweed is found throughout Ontario in a wide range of habitats, including in cultivated fields, but is most common in turf.

Identification clues

Seedling

Cotyledons:

They are small oval and shiny green with a very short petiole.

First leaves:

They are oval, dark green in colour and have hairy entire margins and a pointed tip. They grow in opposite orientation. The petioles are hairy.

Mature leaves:

The mature leaves of mouse-eared chickweed are similar to its younger leaves.

Mature plant

Stem:

Its stem is prostrate and densely hairy with swollen nodes that root into the soil when they come into contact.

Flowers:

Mouse-eared chickweed has very small flowers with five white two-lobed petals, which gives it the appearance of having 10 petals.

Fruit:

The fruit of mouse-eared chickweed is contained in an oval capsule. It is reddish- brown to rusty in colour and triangular to angular shaped.

Roots:

Fibrous roots, because of its prostrate habit, it can form new roots at the nodes.

Note of interest

Mouse-eared chickweed has very hairy, round to ovate leaves shaped like mouse ears, hence the name.

Often mistaken for

I know it's not Grass-leaved stitchwort because grass-leaved stitchwort is hairless compared to the densely hairy mouse-eared chickweed.

I know it's not Common chickweed because mouse-eared chickweed is dark green and has densely hairy leaves and stems while chickweed is pale green and is almost hairless except for a single line of hair on one side of the stem.