Narrowleaf bittercress - an emerging invasive in Arlington

The identity of an invasive plant newly spotted in the iNaturalist Invasives ArMI project was recently confirmed by an iNaturalist identifier as being narrowleaf bittercress (Cardamine impatiens). Observation: https://www.inaturalist.org/observations/114187428

As a single plant, it is unassumingly frilly and not too large, but its seeds eject from garlic mustard-style skinny seed pods to establish large colonies very quickly. Like garlic mustard, it is in the mustard family.

The above specimen was observed at the Arlington Reservoir, in its preferred habitat around watercourses (streams, ditches, floodplains). Viewing iNat's collection of photos (https://www.inaturalist.org/taxa/159836-Cardamine-impatiens/browse_photos ) will help familiarize you with how it looks at all different times of year.

Thank you for this observation at the Arlington Reservoir near the native gardens. Now we all can be on the look out, especially around waterways.

Read More from the Lower Hudson Partnership for Regional Invasive Species Management (LHPRISM), which rates this plant as highly invasive in NY. ( https://www.lhprism.org/species/cardamine-impatiens )
.Highlights:

• often establishes around watercourses such as ditches, streams, and on floodplains although it is common in the dappled shade of disturbed woodlands too
• The species is a prolific producer of viable seed and is self-fertile: a single plant can quickly become a smothering colony.
• impacts on spring ephemeral populations may be significant; it tends to die back by July, but it is not gone!
• The seed pods explode (explosive dehiscence) ! Other ways seed spread are water, birds, mammals, and human recreation.
• Control by hand pulling or digging young plants prior to seed set.
• Narrowleaf bittercress can be composted unless the plant has already formed viable seed heads, in which case all reproductive parts must be bagged and disposed of.
• All managed infestations should be monitored for at least several years to monitor for new seedlings and to prevent reinvasion from nearby populations

Posted on 28 de fevereiro de 2023, 10:14 PM by ecrow