It usually germinates in spring, though it’s not uncommon for it to germinate at any time of the year. The seeds of this species can remain dormant for more than 30 years.

The stems are short and creep along the ground, with flowering stems generally more upright. The leaves are hairy and shaped like the ears of a mouse, in opposite pairs. Each leaf is up to 25 millimetres long by 10mm wide. The lower leaves have stalks and the upper ones are stalk-less. Chickweed is very similar, but the leaves tend to be hairless, while the stems do have hairs.

Annual Mouse-ear Chickweed is a related species. The leaves of this species are more yellow to light green, with glandular hairs that give the weed a sticky feeling when touched.

Field Chickweed is a rhizomatous, mat-forming perennial, mostly found in the east side of the South Island. Unmowed, it can be up to 30 centimetres tall, with flowers up to 2cm across in loose clusters.