Sticky chickweed (Cerastium glomeratum)

Synonyms: Cerastium viscosum, Cerastium acutatum, Alsine glomerata, Cerastium viscosum var. glomeratum, Cerastium vulgatum var. glomeratum, Cerastium glomeratum var. apetalum

Common Names: Clammy chickweed, Sticky mouse-ear chickweed, Mouse-ear chickweed

Description:

Sticky chickweed (Cerastium glomeratum) is a small annual in the pink family, introduced to North America from Europe and now common on disturbed ground [1][6]. Its stems and leaves are covered in tiny glandular hairs that give the whole plant a sticky feel ? the trait it is named for [1]. MISIN tracks it as a widespread non-native weed [6], and because several similar chickweeds grow in the same lawns and beds and are easily mixed up [2][3][4].

Habit:

Sticky chickweed is a low, soft, weedy plant, usually somewhere between 2 and 18 inches tall [1]. Its leaves grow in pairs facing each other along the stem, each one roughly a quarter-inch to a bit over an inch long and shaped like a spoon or a narrow egg [1]. The undersides are noticeably fuzzy [1].

The feature worth learning is the texture. The hairs on the stems are glandular ? tipped with tiny sticky glands ? so the plant feels slightly tacky rather than merely fuzzy, and dust and soil grains often cling to it [1]. That single check separates it from common chickweed, the plant it is most often confused with, which is not sticky at all [2].

The flowers are small and white, with five petals and ten stamens, and they sit crowded together toward the stem tips [1]. Small dry capsules follow, about 7 to 10 mm long, which split open at the top to release the seeds [1].

This is an annual ? it grows, flowers, seeds, and dies within a single year [1]. That makes it a plant of the cooler, wetter part of the growing season in lawns and garden beds, and it means the practical window for doing anything about it closes once the capsules ripen.

At-a-glance cues:

1. Stems feel sticky, not just hairy ? the hairs are gland-tipped [1]
2. Leaves in facing pairs, spoon-shaped to oval, fuzzy underneath [1]
3. Small white flowers with five petals and ten stamens, crowded near the stem tips [1]
4. A low annual, roughly 2 to 18 inches tall, on disturbed or maintained ground [1]

Leaves:

1. Arrangement: opposite ? two leaves per node, facing each other [1]
2. Shape: spoon-shaped, oval, or widest above the middle [1]
3. Size: about 5 to 30 mm long [1]
4. Surface: the underside is fuzzy or hairy [1]
5. Stalk: leaves sit close against the stem [1]

Stems:

1. Habit: a soft-stemmed annual herb, about 5 to 45 cm (roughly 2 to 18 inches) tall [1]
2. Surface: hairy, with a mix of plain hairs and gland-tipped hairs between the nodes [1]
3. Texture: slightly sticky to the touch because of those glandular hairs [1]

Flowers:

1. Color: white [1]
2. Parts: five separate petals and five separate sepals, with ten stamens [1]
3. Arrangement: crowded together toward the tips of the stems [1]

Fruit and seeds:

1. Fruit: a capsule that splits open at the top when dry to release the seeds [1]
2. Size: about 7 to 10 mm long [1]
3. Role in spread: the only route ? this is an annual, so every plant next season grows from seed shed this one [1]

Habitat:

Sticky chickweed is not native to North America. It was introduced from Europe and has become common in many areas [1]. Its US nativity is classified as exotic [6].

It grows on human-disturbed and human-maintained ground [1] ? lawns, garden beds, vegetable rows, driveway edges, roadsides, and any patch of open soil that is regularly walked on, mown, or turned over.

It is a plant of openings rather than of intact plant communities. Where the ground stays covered ? by dense turf, by mulch, or by established plantings ? it has much less to work with.

Reproduction:

Sticky chickweed is an annual, so its entire life happens within one season [1]. It sprouts, grows into a low leafy plant, flowers, sets seed, and dies. There are no persistent roots or creeping stems to carry it into the following year.

Seed is the only way it continues. Each small capsule splits open at the top when dry and releases its seeds onto the ground below [1] ? mostly right where the parent plant stood, which is why patches tend to thicken in place rather than jump across a yard.

It typically arrives as seed carried in on something: in the soil of nursery plants, in topsoil or fill, on boots, or on mower decks and garden tools moved between beds. Cleaning soil off tools and tires between jobs does more to keep it out than anything you can do once it is established.

The control window follows directly from the annual habit. Removing plants before the capsules ripen stops that year's seed entirely, and because nothing survives underground, a season of consistent removal makes real progress rather than just buying time.

Impact and Damage:

No source reviewed for this sheet reports that sticky chickweed is toxic to people, pets, or livestock, and none describes it as causing skin irritation.

For a homeowner it is a lawn and garden weed. It fills gaps in turf and takes up space in beds and vegetable rows, competing with what was planted there for room, light, and water.

No documented ecological harm was found in the sources reviewed for this sheet, and none is claimed here. What is established is narrower: it is a small non-native annual of disturbed and maintained ground [1][6]. It is not documented as invading or degrading intact natural plant communities.

The practical value in recording it accurately is that several chickweeds look alike and share the same habitats [2][3][4][5]. Distribution data for any one of them is only as good as the identifications behind it.

Similar species:

Several chickweeds turn up in the same lawns and beds, and all of them are introduced rather than native.

Common chickweed (Stellaria media) is the one most often confused with sticky chickweed, and the texture test settles it. Common chickweed is not sticky ? its sap is clear and watery, and instead of being hairy all over, it carries its hairs in narrow lines running down the stem from each pair of leaf bases [2]. Its petals are so deeply split at the tip that a five-petaled flower can look like it has ten [2], and some of its leaves have distinct stalks while sticky chickweed's sit close against the stem [1][2].

Common mouse-ear chickweed (Cerastium fontanum) is a close relative and the harder call, but two things separate it. It is a perennial that lives for years, not an annual [1][3], and it spreads by creeping runners to form low mats, with stems that trail along the ground before turning up at the tips [3]. Its hairs are also plain rather than gland-tipped ? no glands on the leaves or stems ? so it does not feel sticky [3].

Giantchickweed (Stellaria aquatica) does share the sticky glandular hairs, so touch will not separate this one [4]. Size and habitat will. It is a perennial reaching up to about 3 feet tall, far larger than sticky chickweed [1][4], and it grows in wet places ? river and stream floodplains, lake and river shores, and damp woods [4] ? rather than in lawns and dry disturbed ground.

Field chickweed (Cerastium arvense) also has glandular hairs [5], but its flowers give it away. Its petals are 10 to 15 mm long [5], making it far showier than sticky chickweed's small white flowers. It is a perennial as well, living for years rather than one season [1][5].

Monitoring and rapid response:

Signs to watch for:

1. Low, soft, hairy plants filling gaps in lawns, garden beds, and vegetable rows [1]
2. Stems that feel sticky rather than simply fuzzy [1]
3. Paired spoon-shaped leaves, fuzzy on the underside [1]
4. Small white five-petaled flowers crowded near the stem tips, followed by small dry capsules [1]

What you can do:

1. Pull it by hand. The plant is shallow-rooted and comes up easily, especially when the soil is damp, and there is nothing left underground to regrow [1].
2. Get it before the capsules ripen. This is an annual [1], so seed is the only thing carrying it forward ? remove plants while they are flowering or earlier and that year's seed never happens.
3. Hoe or cultivate beds and rows to take out seedlings while they are small. Repeat through the season, since new ones keep appearing on open soil.
4. Mulch bare ground in beds. This plant needs open disturbed soil to establish [1], and a covered surface removes the opening.
5. Keep turf thick. Gaps in a lawn are where it gets in, so anything that thickens the grass reduces the room available to it.
6. Clean soil off boots, tools, tires, and mower decks between areas. Seed moves in soil, and that is usually how a new patch starts.
7. For a natural area crew: low priority. This is a disturbed-ground annual with no documented natural-area impact, so effort is better spent elsewhere ? but accurate identification is worth the moment it takes, since several chickweeds share these sites [2][3][4][5].

When to call a professional:

1. Rarely needed for a homeowner. The most useful outside help is confirming which chickweed you have, since four similar species grow in the same places [2][3][4][5]
2. For chemical control options, contact a licensed applicator or your local cooperative extension office.

Report sightings to MISIN. Help track this species' spread by submitting observations through the MISIN web site or the MISIN mobile app (Android, iOS, Windows, and macOS). Photos at multiple angles paired with a precise GPS location are the most valuable data for confirming new occurrences and triggering rapid-response review.

Credits:

1. Native Plant Trust, Go Botany. Cerastium glomeratum (sticky chickweed). gobotany.nativeplanttrust.org
2. Native Plant Trust, Go Botany. Stellaria media (common chickweed). gobotany.nativeplanttrust.org
3. Native Plant Trust, Go Botany. Cerastium fontanum (common mouse-ear chickweed). gobotany.nativeplanttrust.org
4. Native Plant Trust, Go Botany. Stellaria aquatica (giant chickweed). gobotany.nativeplanttrust.org
5. Native Plant Trust, Go Botany. Cerastium arvense (field chickweed). gobotany.nativeplanttrust.org
6. Invasive Plant Atlas of the United States. Sticky chickweed, Cerastium glomeratum. University of Georgia Center for Invasive Species and Ecosystem Health. invasiveplantatlas.org
7. Plants of the World Online. Cerastium glomeratum Thuill. Royal Botanic Gardens, Kew. powo.science.kew.org

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