Arlington, MA Invasives "ArMI" Army's Journal

May 15, 2024

Need a reason to remove garlic mustard ...?

... besides that it puts down poison into the soil that prevents native seeds from germinating?

Here's one involving butterflies.

The spread of garlic mustard is causing the West Virginia White butterfly (Pieris virginiensis) to decline in number.

This butterfly with translucent white wings depends crucially on native two-leaved toothwort (Cardamine diphylla) as its host plant. ( https://www.flyingtrillium.com/blog/cardamine-diphylla-toothwort )

The specialist relationship between plant and insect means that W. Virginia Whites seek out two-leaved toothwort to lay eggs on. W. Virginia White caterpillars have specially evolved to eat the strawberry-like leaves of toothwort; they can survive on this and only one other toothwort called cutleaf toothwort (Cardamine contatenata) - (https://www.wildflower.org/plants/result.php?id_plant=caco26 ). Two-leaved toothwort also hosts the falcate orange-tip butterfly (https://plants.ces.ncsu.edu/plants/cardamine-diphylla/ ). Specialized bees known as Andrena arabis collect pollen from Cardamines.

But now that garlic mustard has been introduced into North America, its spread is threatening West Virginia White survival. Unfortunately garlic mustard fools West Virginia Whites into laying eggs on it instead of its appropriate toothwort hosts. When West Virginia white caterpillars hatch on garlic mustard and try to feed, they die because they cannot digest garlic mustard leaves.

We now have a reason to reintroduce two-leaved toothwort and cutleaf toothwort into our woodland landscapes, while also removing garlic mustard -- it will save a butterfly's life.

Posted on May 15, 2024 06:55 PM by ecrow ecrow | 0 comments | Leave a comment

January 22, 2024

Marching North - Range-shifting Invasive Plants

Many beloved garden species brought to North America from elsewhere have proven themselves invasive further south in the Mid-Atlantic states. These include romantic wisteria (Wisteria sinensis, Wisteria floribunda), reminiscent of old-fashioned gardens, fragrant butterfly bush (Buddleja davidii), and many common groundcovers, including vinca. With climate change, research anticipates these species will take up residence in New England, if they haven't already, posing new threats to our ecosystem.

While this new threat is daunting, range-shifting invasive plants also create a rare opportunity for proactive invasive plant management. The identities of problematic invasive plants in the United States are already known, and tools such as the Invasive Range Expanders Listing Tool (https://www.eddmaps.org/rangeshiftlisting) can project which species may soon arrive. (Coville, et. al., 2021)

A 2021 article published in Invasive Plant Science and Management ( https://par.nsf.gov/servlets/purl/10294548 ) examines the issue of northward marching invasives as the New England climate warms. www.cambridge.org/inp

By examining which plants are most likely to have major negative ecological impacts in New England, the authors hope to promote early detection and prevention. This article creates a watch list of twenty-two invasive plants that could threaten New England open spaces, to guide environmental planners. Many of these invasives also can impact agriculture economically, and unfortunately, most are still available for purchase at ornamental plant retailers or online.

The authors recommend that New England states proactively include these 22 plant species in future weed risk assessments. This strategy would prohibit the deliberate sale and planting of high-risk species as ornamentals and/or seed imports.

Some of these northward roaming invasives have already reached Massachusetts and are threatening enough to have made the Massachusetts Prohibited Plant list.

  • Porcelain Berry (Ampelopsis glandulosa): Neon blue or pink berries and fancy, deeply lobed leaves are the hallmark of this vine, found most frequently in the Arlington Town gardens, but spreading elsewhere - https://www.invasive.org/browse/subinfo.cfm?sub=78266

  • Chinese Wisteria (Wisteria sinensis): Who doesn't love draping wisteria blooms? But this invasive found on the bike path near the Bow/Frazer St. entrances climbs up trees, stretches in long, above-ground runners across the landscape to re-root, and puts down very deep roots nearly impossible to dig out. It is listed as invasive across mid-Atlantic and Appalachian states as far north as Rhode Island. https://www.invasive.org/browse/subinfo.cfm?sub=3083

  • Others have not yet reached invasive status in Massachusetts. But because they are invasive further south, early monitoring and control can help prevent the damage these plants inflict on ecosystems. We can do our part by declining to buy and plant these in our yards and gardens. A sampling:

  • Vinca (Vinca major): This very familiar ground cover is listed as invasive in Rhode Island, but is commonly sold in Massachusetts nurseries. Landscapers love this as their go-to solution for slopes. Vinca has been around a long time. Introduced from Europe in the 1700's, it is commonly found around old homesites. From these sites it has spread in dense mats into both open and dense woodlands. https://www.invasive.org/browse/subinfo.cfm?sub=4528


  • Paper mulberry (Broussonetia papyrifer): While it's only officially invasive in the Pennsylvania, New Jersey, Maryland region, it is creeping northward. Paper mulberry has been spotted in southern Rhode Island, and Essex county, MA - https://www.invasiveplantatlas.org/subject.html?sub=5208

  • Crimson Fountain Grass (Cenchrus setaceu): This ornamental grass, found in Virginia and Maryland, has not yet been reported in New England. https://www.invasiveplantatlas.org/subject.html?sub=6165

  • See the full list of 22 invasives to be monitored by following the article link below.

    Citations: Coville W, Griffin BJ, and Bradley BA (2021). Identifying high-impact invasive plants likely to shift into northern New England with climate change. Invasive Plant Sci. Manag. doi: 10.1017/inp.2021.10 - https://par.nsf.gov/servlets/purl/10294548

    Posted on January 22, 2024 01:55 AM by ecrow ecrow | 0 comments | Leave a comment

    November 07, 2023

    Controlling Arlington Invasives This Fall

    To help you plan your invasives removal work, here's a list of the most common Arlington invasives that have set seed in the Fall or still have above ground vegetation. Removing the seed-bearing branches can prevent build up in the seed bank. So you have time to help your yard and Arlington parks / open space before winter.

    Target FALL Invasives

  • Roundleaf Bittersweet (formerly Oriental bittersweet): The berries of Roundleaf Bittersweet have now opened their yellow capsules to reveal the soft red berries within. You still have a chance to prevent further spread next spring. Get the berries off of female plants first, dig out roots before hard frost, and help the ArMI in the bittersweet brigade this winter! We will cut big vines for as long as the weather allows.

  • And more info: This Invasive has both male and female plants.

  • First priority is always to remove berries which progress in color from green to a yellow outer capsule to an orange-red soft inner fruit by Fall. Bittersweet berries at Turkey Hill: https://www.inaturalist.org/observations/141808750
  • Bittersweet rather innocently enters yards under bushes and hedges when birds eat Fall berries and deposit seeds where they roost. It’s best to get it out young when hand pulling is easy.
    Here’s what young bittersweet looks like: https://www.inaturalist.org/observations/185164652 .
  • Bittersweet becomes extremely problematic if not removed early. There are many examples in Arlington of monstrous thick vines winding around trees, weighing down branches, and ultimately strangling and killing them. Old vines at McClennen Park: https://www.inaturalist.org/observations/150492165
  • Mature bittersweet is best clipped with loppers and dug out by roots if not in conservation areas. Extra time spent removing roots at the start saves much time in the long run.
  • Invasive Knotweed - Knotweed vegetation hasn't yet died back, so digging out by the roots can still reduce a stand. Cutting this time of year will be unlikely to have much effect, since knotweed will soon die completely back for the winter. Remember, if you find knotweed in your yard away from wetlands, streams and ponds. DIG IT OUT with a strong shovel, or cut it multiple times throughout the growing season, starting in June, after it uses up stored energy to push out 4-6 ft canes.

  • What about the other Arlington invasives?

    Though now is not the optimal time to remove, some actions can still be taken.

  • Black swallowwort: This vine is now past the optimal control months of June through early September. But if you earlier cut back the vines to remove pods, there's still a window of time to remove the roots before hard frost.

  • Bittersweet nightshade: The berries have mostly ripened and seeds dropped by late Oct / early Nov. But the stems and leaves are still present, so pull them if you see them. What does this plant look like? Dark green deeply notched leaves are often found with a three-part form somewhere on the plant, the purple flowers with yellow tongues sticking out of the flower, and bright red ripe berries. ( https://www.inaturalist.org/observations/178719057 ). Check near rock walls, sidewalks, and in hedges. This invasive seems to like more alkaline conditions.

  • Asiatic Dayflower: Asiatic dayflower is an annual, so it has mostly done it's seed distribution for the year. It is still green in spots with withered flowers. Pulling now might capture some remaining seeds in the withered flowers, but just remember not to put the material in Fall compost. It should be black bagged and marked as "Invasive weeds".
    Remember: This short rather cute annual with gorgeous blue flowers is deceptive. Wherever it gains a toehold, it completely covers the landscape, preventing other vegetation from germinating. It's satisfying to weed out because it's easy to pull. See examples of how this invasive completely takes over an area by visiting the bike path at Bow St. and Frazer Lane in Arlington. It flowers all summer long into November, so monthly weeding is best.

  • iNaturalist Links:
    Blackswallow-wort at Frazer and Mill Lane: - https://www.inaturalist.org/observations?nelat=42.42691328029149&nelng=-71.17663531970851&place_id=any&swlat=42.4242153197085&swlng=-71.17933328029152&taxon_id=208963&user_id=ecrow&verifiable=any

    Asiatic Dayflower at Frazer/Mill Lane: https://www.inaturalist.org/observations?nelat=42.42691328029149&nelng=-71.17663531970851&place_id=any&swlat=42.4242153197085&swlng=-71.17933328029152&taxon_id=52927&user_id=ecrow&verifiable=any

    Bittersweet nightshade at Ryder St.: https://www.inaturalist.org/observations?nelat=42.42660718029149&nelng=-71.17251691970849&place_id=any&swlat=42.42390921970849&swlng=-71.1752148802915&taxon_id=55620&user_id=ecrow&verifiable=any

    Knotweed at Frazer/Bow: https://www.inaturalist.org/observations?nelat=42.42691328029149&nelng=-71.17663531970851&place_id=any&swlat=42.4242153197085&swlng=-71.17933328029152&taxon_id=914922&user_id=ecrow&verifiable=any

    Posted on July 20, 2023 07:42 PM by ecrow ecrow

  • Posted on November 07, 2023 07:08 PM by ecrow ecrow | 0 comments | Leave a comment

    Woody Invasive: Glossy Buckthorn (GB)

    Glossy buckthorn (Frangula alnus) reproduces primarily from seed, relying on dispersal by birds, small mammals, and gravity. Importantly, medium to fullsize glossy buckthorn trees potentially produce 430-1,560 offspring per year, making seed propagation its primary mode of reproduction.

    When glossy buckthorn invades a woodlands it changes the growing conditions in the following ways:
    • Decreases soil pH; the soil becomes more acidic
    • Lowers the water table, making it less accessible to plants with shorter root systems
    • Decreases light reaching the understory and shades out native species
    • May produce compounds that prevent germination of other plants (allelopathic effects), similar to common buckthorn

    ( https://www.michigan.gov/-/media/Project/Websites/invasives/Documents/Response/Status/egle-ais-frangula-alnus.pdf?rev=6d5550e9d1bc4c538ef72a11564e0f7f )

    These changes impact vegetation and animal life of a woodlands.
    • Decreases presence of native grasses and even shade tolerant sedges
    • Reduces the total plant cover, especially of native saplings
    • Lowers survival of native saplings because increased shade starves them of life-giving light
    • Alters both the number and diversity of pollinators
    • GB monocultures harm habitats that songbirds call home; nesting here exposes them to greater predation
    • Creates environments in which exotic earthworms thrive

    REMOVAL & CONTROL: The method chosen for removal is critical! Cutting glossy buckthorn without removing the roots not only stimulates vigorous growth of stump sprouts, but these sprouts can produce fruit even within the same season. Uprooting is far better.

    One source of optimism. Glossy buckthorn is extremely shade intolerant. So if upper canopy native trees are allowed to progress naturally toward more mature successional stages, glossy buckthorn might be choked out. On the other hand, opening up the light in the woodlands by removing trees or pruning limbs will give any glossy buckthorn present an unfortunate population boost. After maintenance that adds light to the woodland, follow up the following few years to remove buckthorn seedlings that may have sprouted.

    MORE INFORMATION:
    • "What We Know About Glossy Buckthorn" by UNH Extension Forestry Information Specialist Karren Bennett
    • GLOSSY BUCKTHORN (Frangula alnus) - PEI Invasive Species Council - https://peiinvasives.com/glossy-buckthorn/

    And a similarly invasive related shrubby tree - COMMON BUCKTHORN

    • COMMON BUCKTHORN -- NEW YORK INVASIVE SPECIES (IS) INFORMATION
    New York State's gateway to science-based invasive species information
    https://nyis.info/invasive_species/commonbuckthorn/

    Posted on November 07, 2023 06:42 PM by ecrow ecrow | 0 comments | Leave a comment

    July 20, 2023

    June/July Arlington Invasives Work

    To help you plan your invasives removal work, here's a list of the most common Arlington invasives that are flowering and beginning to set seed in the months of June and July. The seed on most of these plants matures between late July through Fall. So you have time to gradually remove a bit each week in yards or Arlington parks and open space.

    Black swallowwort: Our Monarch butterflies will thank you for getting this plant out of your yard and Arlington open spaces. Monarchs lay eggs on this milkweed imposter, but the caterpillars die trying to eat it. To remove, use a large garden fork to loosen soil and lift plant from underneath to get all the roots. Large stands are best removed in two parts. First go through and quickly clip all vines to about 6 inches from the soil. Remove and bag to stop flowers from setting seed and remove pods before they split open. You now have more time for the next stage of removing by the roots as described above.

    Roundleaf Bittersweet (formerly Oriental bittersweet): This Invasive has both male and female plants. First priority is always to remove berries which progress in color from green to a yellow outer capsule to an orange-red soft inner fruit by Fall. (Bittersweet berries at Turkey Hill: https://www.inaturalist.org/observations/141808750 ) Bittersweet rather innocently enters yards under bushes and hedges when birds eat Fall berries and deposit seeds where they roost. It’s best to get it out young when hand pulling is easy. Here’s what young bittersweet looks like: https://www.inaturalist.org/observations/185164652 . Bittersweet becomes extremely problematic if not removed early. There are many examples in Arlington of monstrous thick vines winding around trees, weighing down branches, and ultimately strangling and killing them. (McClennen Park: https://www.inaturalist.org/observations/150492165 ) Mature bittersweet is best clipped with loppers and dug out by roots if not in conservation areas. Extra time spent removing roots at the start saves much time in the long run.

    Bittersweet nightshade: Nightshade is quite poisonous to pets and humans. Note the deeply notched, three-part leaves present somewhere on the plant, the purple flowers with yellow tongues sticking out of the flower, and bright red ripe berries. ( https://www.inaturalist.org/observations/178719057 ). Check near rock walls, sidewalks, and in hedges. This invasive seems to like more alkaline conditions. Get the berries while green if you can't get this nightshade out of a wall by the roots.

    Asiatic Dayflower: This short rather cute annual with gorgeous blue flowers is deceptive. Wherever it gains a toehold, it completely covers the landscape, preventing other vegetation from germinating. It's satisfying to weed out because it's easy to pull. See examples of how this invasive completely takes over an area by visiting the bike path at Bow St. and Frazer Lane in Arlington. It flowers all summer long into November, so monthly weeding is best.

    Invasive Knotweed - help in the effort to cut this multiple times during the summer. If you find it in your yard away from wetlands, streams and pods. DIG IT OUT with a strong shovel, or cut it multiple times throughout the growing season, starting in June, after it uses up stored energy to push out 4-6 ft canes.

    iNaturalist Links:
    Blackswallow-wort at Frazer and Mill Lane: - https://www.inaturalist.org/observations?nelat=42.42691328029149&nelng=-71.17663531970851&place_id=any&swlat=42.4242153197085&swlng=-71.17933328029152&taxon_id=208963&user_id=ecrow&verifiable=any

    Asiatic Dayflower at Frazer/Mill Lane: https://www.inaturalist.org/observations?nelat=42.42691328029149&nelng=-71.17663531970851&place_id=any&swlat=42.4242153197085&swlng=-71.17933328029152&taxon_id=52927&user_id=ecrow&verifiable=any

    Bittersweet nightshade at Ryder St.: https://www.inaturalist.org/observations?nelat=42.42660718029149&nelng=-71.17251691970849&place_id=any&swlat=42.42390921970849&swlng=-71.1752148802915&taxon_id=55620&user_id=ecrow&verifiable=any

    Knotweed at Frazer/Bow: https://www.inaturalist.org/observations?nelat=42.42691328029149&nelng=-71.17663531970851&place_id=any&swlat=42.4242153197085&swlng=-71.17933328029152&taxon_id=914922&user_id=ecrow&verifiable=any

    Posted on July 20, 2023 07:42 PM by ecrow ecrow | 0 comments | Leave a comment

    February 28, 2023

    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 February 28, 2023 10:14 PM by ecrow ecrow | 0 comments | Leave a comment

    January 18, 2023

    New Additions to State Prohibited Plant

    Three new plants have been added to the Invasisive ArMI project following their addition to the MA state prohibited plants list. https://www.mass.gov/service-details/massachusetts-prohibited-plant-list

    • Scotch Broom (Cytisus scoparius)
    • Weeping Lovegrass (Eragrostis curvulam or Eragrostis on iNaturalist
    • Japanese Black Pine (Pinus thunbergii)

    The state has announced a phase-out period for these newly listed prohibited species. As of December 31, 2022, plant nurseries and growers can no longer receive or begin propagation of these three plants.

    Existing stock received or propagated before this date may be sold according to the following schedule:

    Eragrostis curvula (Weeping Lovegrass): No sales permitted after 12/31/2023
    Cytisus scoparius (Scotch broom): No sales permitted after 12/31/2024
    Pinus thunbergii (Japanese Black Pine): No sales permitted after 12/31/2025

    Posted on January 18, 2023 07:13 PM by ecrow ecrow | 0 comments | Leave a comment

    September 15, 2022

    The Keystone Value of Places like Arlington's Hill’s Hill

    Hill’s Hill is a small wooded hill in Arlington sandwiched between lower Washington St. and a Park and Rec Department soccer field. In a shadier portion at the top, black swallow-wort (BSW) took hold some years back and spread, blanketing oak and hickory seedlings and blocking access to light. The Invasives ArMI chose this site for BSW removal and eventual renewal with native replacements. We are happy to report that the previously overrun tree seedlings have survived. https://www.inaturalist.org/observations/84479644

    As we've worked each week on the Hill this summer, we gradually noticed its valuable assets, delineated here: https://drive.google.com/file/d/13Se57e89x_TuL9jtBZkkVxH9XhMPibNj/view?usp=sharing

    By traditional standards for measuring old growth forests —a measure of girth at chest height (DBH)— Hill’s Hill does not compare with a large forest. But then Arlington is not in the middle of Maine either. We have to value what we have.

    The value of an ecosystem goes beyond the number of mature trees. It includes its future potential, and the variety of species supported right now.

    Numerous tree seedlings and saplings at Hill’s Hill, such as oak ( https://www.inaturalist.org/observations/135167983 ), cherry (top 2), aspen-poplar, and hickory, contribute to its future potential. Anything growing right now has already found a nourishing spot with the right mix of sun, soil, and water. Just because it’s little doesn’t mean we shouldn’t protect it. The root systems of these naturally sprouted trees have perhaps more value than what we see above ground... it's what's going to help these trees survive during a drought like the one just experienced, whereas a planted "replacement" tree will more likely die.

    High value current habitat can be measured by the numbers of species supported. Trees, being large, tend to support the most. But certain shrubs are numbered among the top Keystone plants. For example, blueberry is the only shrub genus to make it into the top 10 Trees & Shrubs (at number 7) as researched by Doug Tallamy, entomologist at University of Delaware. Keystone plants support the pollinator/caterpillar base of Arlington's ecosystem. According to this zip-code-specific National Wildlife Federation database ( https://www.nwf.org/NativePlantFinder/Plants ), the genus Vaccinium (blueberries, cranberries) hosts a whopping 282 soft-bodied caterpillars and other insect larva that birds in Arlington depend on to feed their babies.

    Fortunately, there's a substantial blueberry patch at Hill's Hill protecting a down slope at the edge of the meadow from erosion. ( https://www.inaturalist.org/observations/133465271 ) We can add this asset to the sumacs anchoring the remaining meadow edge. ( https://www.inaturalist.org/observations/127432733 ) And the blackberry patch that John Eastman (Forest and Thicket) characterizes as a natural tree nursery. (https://www.inaturalist.org/observations/127433059 )

    ===
    The National Wildlife Federation explains the importance of Keystone species, and offers a general list of Keystone Native Plants in the Eastern Temperate Region.
    • "Native plants have formed symbiotic relationships with native wildlife over millions of years, creates the most productive and sustainable wildlife habitat.
    • "Keystone plant genera are unique to local food webs within eco-regions. Remove keystone plants and the diversity and abundance of many essential insect species, which 96% of terrestrial birds rely on for food sources, will be diminished. The ecosystem collapses in a similar way that the removal of the “key” stone in ancient Roman arch will trigger its demise."

    National Wildlife Federation Keystone (NWF) dbase by zipcode: https://www.nwf.org/NativePlantFinder/Plants

    NWF Keystone pdf: https://www.nwf.org/-/media/Documents/PDFs/Garden-for-Wildlife/Keystone-Plants/NWF-GFW-keystone-plant-list-ecoregion-8-eastern-temperate-forests.ashx?la=en&hash=1E180E2E5F2B06EB9ADF28882353B3BC7B3B247D

    Posted on September 15, 2022 08:57 PM by ecrow ecrow | 0 comments | Leave a comment

    September 06, 2022

    Be on the watch for Japanese Hops

    Japanese hops (Humulus japonicus) are the new invasive weed in town. They are an annual vine with palmate leaves which have 5-7 lobes, and look a little like a Virginia creeper. It's easy to tell the difference though; Japanese hops have hooked hairs or barbs along the leaves and stem. If you try to brush past one, it will grab you, and if you try to pull one, wear gloves and sleeves. My forearms are covered in welts from the 5 minutes of vine removal before I got adequate protection.

    This plant has spread from several sites around the Northeast, but it hasn't been around Arlington until this summer. A couple moved into the neighborhood last fall, and decided to remove the front lawn and plant for pollinators. They went to a wonderful local garden center which stocks native plants (Mahoney's) and bought some pollinator and hummingbird seed mix from Earth Science brand. Unfortunately, that seed mix was contaminated with Japanese hops.

    I watched their wildflowers come in this spring, and this summer I noticed the vine taking over their pollinator meadow. Unfortunately I didn't identify it until after I found a plant in my yard. In one season, the vines took over their whole front yard, their shrubs, and climbed higher than I could reach (while standing on a chair) up their Kousa dogwood. On top of that, in this one season it produced seeds which spread to my yard on the wind, and the plant in my yard was already flowering when I found it. That is scary.

    Our new neighbors were on board with the removal, after I explained what the vine was. They helped me for hours in the hot sun, and gave me lots of seltzer water. We removed the plants, and tried to carefully bag all of the seed-heads, and they will keep an eye our for more. There will be more, and not just in their yard; I expect it will be all around the area near Scituate Street, between Grey St. and Mass Ave. There were lots of seeds, which spread on the wind before we started removing it, and we probably disturbed and spread some while removing the vines.

    I wanted all of you to know about it, because I need people to help keep an eye our for me. I will be moving to Acton in October (2022) and though I plan on coming back to check, it only takes one missed plant to spread further. I really hope that the spread stops with the area around Scituate Street and Mnt. Vernon. These nasty vines can grow 35 feet in a season, and start producing spikes of white flowers after only a few weeks. They also kill other plants with allelopathic (soil chemistry) effects [1,2]. Never have I ever seen a vine that could take over shrubs and meadows as quickly as Japanese hops do here.

    [1] https://extension.umass.edu/landscape/weeds/humulus-japonicus
    [2] https://www.invasive.org/browse/subinfo.cfm?sub=10091

    P.S. On top of all the awful things this vine can do to the ecosystem, it can also do some pretty uncomfortable things to you. Wear protection. It seems harmless and easy to pull, if a bit prickly, but those welts it gave me burned for hours. Wear a mask if you have allergies; apparently it is a moderate allergen, but it uses wind-pollination, so it produces a profusion that will puff up into the air as you pull the vine.

    Posted on September 06, 2022 11:33 PM by efputzig efputzig | 1 comment | Leave a comment

    May 21, 2022

    Dames Rocket - Its Emerging Presence in Arlington

    This spring I was surprised to discover a very large 2 1/2 foot upright plant with buds clustered at the top in an un-managed, shared right of way bordering a neighboring yard . It definitely was not present last year, at least not in this form. I took a picture, iNaturalist tentatively identified it as Dames rocket, and I placed it on my "watch" list. In a week's time, it had added another 6 inches to its height and the clustered buds were now spread out a bit along the stem, in addition to the terminal cluster. The lower leaves of this plant were bigger than my hand!

    Then I saw another https://www.inaturalist.org/observations/117726465 . This time along the bike path at Bow and Frazer, now in full bloom with clusters of beautiful purple flowers looking much like blue phlox (Phlox divaricata: https://www.inaturalist.org/taxa/126419-Phlox-divaricata-laphamii ). Dames rocket flowers differ from phlox in having four petals to the five in the phlox bloom. And these didn't have the light honey aroma of phlox. Again iNaturalist identified it tentatively as Dames rocket. iNaturalist also warned it might be invasive. Unfortunate, because it is so beautiful that I'm sure many homeowners would consider its appearance in their yards to be a gift. A passing bicyclist who, it turned out, is one of the driving forces in the push to clean up Alewife Brook, asked if it was phlox, thus confirming my worry.

    Where did these two dames rocket plants come from? A search of the area revealed that, on the other side of the bike path in a signed and resident-maintained plot of public land, there were several other dames rocket plants. And an ArMI member said she'd seen some up in Whipple Hill. Somehow it's spreading far and wide after some years of remaining contained in the naturalized "garden" plot.

    An iNaturalist search for dames rocket in Middlesex County reveals it is often sited (and sighted) in naturalized areas at the edges of woodlands https://www.inaturalist.org/observations/81646750. This non-native is definitely behaving like it is invasive and indeed it is.

    Dames rocket is on the invasive species list in Massachusetts, a list that is not so easy to get on. A species might spend years on the lesser "likely invasive" or "potentially invasive" lists being evaluated by the Massachusetts Invasive Plant Advisory Group (MIPAG) for the ability to persist in Massachusetts fields, woodlands, and wetlands. Its formal designation as invasive also means it is banned for sale, propagation, and importation https://www.mass.gov/service-details/invasive-plants .The propagation part of this ban just might mean sharing it from your garden with a neighbor is illegal. Perhaps Arlington's Conservation Commission can shed light on this point.

    At any rate, since this invasive can sneak into a garden unrecognized in its first-year rosette form https://www.inaturalist.org/observations/106355669 (Feb 2022, PA), the Invasives ArMI will definitely be removing dames rocket as we find it this season. We will be watching for new blooms in May next year too. If you want to learn to identify it in its various stages, check out this 40-day Pennsylvania observation: https://www.inaturalist.org/observations/106355669

    Posted on May 21, 2022 01:15 PM by ecrow ecrow | 0 comments | Leave a comment