Weeping alkaligrass (Puccinellia distans)

Synonyms: Poa distans, Puccinellia retroflexa, Puccinellia suksdorfii, Puccinellia distans var. tenuis, Glyceria distans, Glyceria pulvinata, Sclerochloa distans

Common Names: Spreading alkaligrass, reflexed saltmarsh grass, slender alkaligrass, European alkaligrass

Description:

Weeping alkaligrass (Puccinellia distans) is a low, tufted grass in the grass family (Poaceae), native to Europe and Asia and introduced to North America in the 1800s [1][2][3]. It is a salt specialist: it grows where the soil is too salty for most other grasses, and it has spread widely along salted, de-iced roadsides [1]. MISIN tracks it as a non-native salt grass that colonizes salt-affected ground and can move into inland saline wetlands [1][3].

Habit:

Weeping alkaligrass is a small, clump-forming perennial grass, from a couple of inches to about 2 feet tall (5 to 60 cm), growing in tufts on salty ground [1]. Its name comes from its flower head: an open, airy spray (panicle) whose lower branches spread outward and bend downward or backward, giving a drooping, "weeping" look [1]. The leaves are narrow, hairless, and often folded or inrolled [1].

It is easiest to notice in summer, from June to August, when the purplish-tinged flower heads are up [1]. Where you find it is itself a clue ? salted roadsides, ditch edges, railroad ballast, salt flats, and salt-affected wet ground, often growing where other grasses have thinned out [1].

At-a-glance cues:

1. A small, tufted grass growing in salty ground ? salted roadsides, ditches, salt flats [1]
2. An open, airy flower head with lower branches that spread and bend downward (the "weeping" look) [1]
3. Narrow, hairless leaves, often folded or inrolled [1]
4. Purplish flower heads in summer (June to August) [1]

Leaves:

1. Arrangement: mostly basal and along the lower stem, 2 to 4 per shoot [1]
2. Blade: narrow, about 1 to 7 mm wide and up to roughly 4 inches long, flat or with folded to inrolled edges [1]
3. Ligule: blunt, smooth, about 1 mm long [1]
4. Surface: hairless, slightly rough [1]

Stems:

1. Habit: tufted and clump-forming, erect, hairless [1]
2. Height: about 2 inches to 2 feet (5 to 60 cm) [1]

Flowers:

1. Arrangement: an open, airy panicle whose lower branches spread outward and bend downward or backward (reflexed) ? the "weeping" habit [1]
2. Spikelets: small, about 1.5 to 2.5 mm long, each with several florets, often tinged purple [1]
3. Bloom time: June to August [1]

Fruit and seeds:

1. Type: a tiny dry grain (caryopsis), elliptic and brown, about 1.5 mm long [1]
2. Dispersal: spread by seed ? carried in water, mud, and on mowers and vehicles along the salted roadsides where it grows [1]

Habitat:

Weeping alkaligrass is native to Europe and Asia and is not native to North America, where it is now widespread [1][3]. What sets it apart is its tolerance of salt: it thrives in saline and alkaline soils that most grasses cannot handle [1].

Look for it in salt-affected, often wet, disturbed ground ? salted and de-iced roadsides, ditches, railroad beds, waste areas, salt flats, and the edges of salt marshes and saline lakeshores [1][3]. Along roads, the salt in winter de-icing runoff creates exactly the salty strip of soil it favors, which is how it has spread across the continent [1].

Reproduction:

Weeping alkaligrass spreads by seed [1]. A homeowner is most likely to encounter it along a salted road or driveway edge, and its seed travels the way roadside plants do ? in runoff water and wet mud, and on mowers, tires, and equipment that pass along the verge [1]. It is a perennial, so established tufts persist and seed year after year.

Its spread is tied to salt: because it can grow where road-salt runoff has made the soil too salty for other plants, it takes hold in that bare, salty strip and holds it [1]. For control, that means two things ? remove tufts before the summer seed heads ripen, and, at a larger scale, reducing salt input to a site lets other plants recover and compete with it [1].

Impact and Damage:

Weeping alkaligrass is not toxic and is not a health hazard to people or pets. It is, in fact, sometimes planted on purpose ? as a salt-tolerant turf or a pioneer plant to cover badly salt-damaged, eroded ground [1].

Its concern as an invader is narrow but real. Because it tolerates salt so well, it can dominate the salt-affected niche ? salted roadsides, ditches, and brackish or saline wet ground ? where it may crowd other plants that are already stressed by salt [1]. The worry for natural areas is that, spreading along salt-treated roads, it can reach inland saline habitats and salt marshes and establish there [1][3]. That said, its documented impact is limited: one assessment found it too uncommon to cause significant economic harm and of little economic importance in North America [3]. MISIN tracks it as a non-native salt grass to watch, especially where it could invade natural saline wetlands rather than as a sweeping threat to ordinary habitats [3].

Similar species:

Weeping alkaligrass is easily confused with other alkali grasses and airy-headed grasses of salty or open ground. Its lower flower-head branches that spread and bend backward, together with its salty habitat, are the best combination to look for [1].

Nuttall's alkaligrass (Puccinellia nuttalliana) is a native alkali grass of saline soils that is very similar, but it is usually taller and its flower-head branches spread less sharply than the strongly reflexed lower branches of weeping alkaligrass [1].

Seaside alkaligrass (Puccinellia maritima) is another salt-marsh alkali grass with the same tufted, salt-loving habit, separated by finer details of its spikelets and flower head, and by its more strictly coastal salt-marsh setting [1].

Tufted lovegrass (Eragrostis pectinacea) has a similar delicate, open flower head, but it has long hairs at the top of its leaf sheaths and grows on ordinary dry, open ground rather than the salty soils that weeping alkaligrass favors [1].

Monitoring and rapid response:

Signs to watch for:

1. A small, tufted grass on salted roadsides, ditch edges, or salt-affected wet ground, often where other grasses have thinned [1]
2. An open, airy flower head with lower branches spreading and bending backward, purplish-tinged, in summer [1]
3. Narrow, hairless, often folded leaves [1]

What you can do:

1. For small amounts, hand-pull or dig the tufts, taking the roots, ideally before the summer seed heads ripen so you do not scatter seed [1].
2. Bag and dispose of seeding plants rather than composting them, and clean seed and mud off mowers, tools, and boots before moving along a roadside so you do not carry it to new stretches.
3. Reduce salt where you can ? using less de-icing salt near garden and natural-area edges lets other plants recover and compete with this salt specialist over time [1].
4. Do not plant it as a salt-tolerant turf near natural saline wetlands, where it could spread into sensitive habitat.
5. For a natural area crew: prioritize protecting inland saline habitats and salt marshes, remove outlying patches before they seed, and work with roadside managers on reducing salt loading where feasible.

When to call a professional:

1. Established stands in or near a natural saline wetland or salt marsh, where careful removal is needed to protect native halophytes
2. Any small tufted grass you cannot confidently identify ? several alkali grasses look alike, so a photo-backed report is worth more than a guess
3. 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. Puccinellia distans (spreading alkali grass). gobotany.nativeplanttrust.org
2. Global Biodiversity Information Facility. Puccinellia distans (Jacq.) Parl. gbif.org
3. Smithsonian Environmental Research Center, NEMESIS Chesapeake Bay database. Puccinellia distans. invasions.si.edu

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