Defining problem plants

Discussion in 'Pacific Northwest Native Plants' started by raingarden, Apr 26, 2020.

  1. raingarden

    raingarden New Member

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    [Edited by wcutler: this was moved from a resource discussion thread, where it was a reply to my statement that "Some of these look like they belong in different resource areas."]
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    Right, native plants don't tend to be considered noxious weeds, although I've noticed that some are very similar to those plants, such as Geraniums, which include both native 'herbal wildflowers' and introduced 'noxious weeds'.

    Another example I've checked out at are plants that look very similar as biennial seedlings, like the noxious wild carrot (Daucus carota) versus the native Daucus pusillus (American wild carrot), as well as the noxious poison hemlock Conium maculatum, and one that is said to have both native and introduced populations, the common yarrow (Achillea millefolium). It may be visually impossible to distinguish between these species for their first year of development, as they may all look like the same rosette. They say that this is typically why people may be killed by the poison hemlock, because they think it is a carrot plant or something similar looking to a native or edible species.

    I'm not sure if there are some plants which are native to some places in the Pacific Northwest and considered noxious in others, but I gather there are various species that are noxious weeds in one state or locality and not in another.

    I checked it out a little bit though, and one example of an invasive species that is also native is something I'd already mentioned, the common yarrow, which is invasive to the Oregon Islands National Wildlife Refuge, because it isn't native to those islands, even though it may be native to the mainland surrounding them. So apparently some of the native species of the Pacific Northwest can also be invasive species within certain areas of it. Strange but true.

    Anyway, I wasn't trying to change the subject. If it isn't typical to consider invasive and poisonous species along with the native ones, whether or not there is some overlap between them, then I was off on a tangent there.
     
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  2. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    1) Native plants can certainly be considered noxious weeds; the "noxious weed" bit is often used to signify something that will harm an agricultural crop. For example, some species of milkweed are native to much of North America, but in some jurisdictions are considered noxious because of crop harm.

    2) The story of yarrow is more complicated than that, as it goes into what is genetically native and not (a species can be native in the broad sense, but its genes may be foreign and deleterious): this is a start, I suppose: Achillea millefolium in Flora of North America @ efloras.org .
     
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  3. raingarden

    raingarden New Member

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    Thanks. It looks like what I was reading about the common yarrow is similar to what qualifies as an invasive garden weed, which could be whatever someone didn't intentionally plant in their garden. Whether or not it interferes with other plants.

    "In the Pacific Northwest, A. millefolium is listed as invasive because it is found in the Oregon Islands National Wildlife Refuge and since it is 'considered a botanical reserve,' all species that are not native to Oregon Islands are considered to be invasive (Tempel et al., 2004)"... Tempel, D. J., A. B. Cilimburg, and V. Wright. "The Status and Management of Exotic and Invasive Species in National Wildlife Refuge Wilderness Areas."

    https://depts.washington.edu/uwbg/research/theses/Lorraine_Brooks_2007.pdf
     
  4. Margot

    Margot Renowned Contributor 10 Years

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    For home gardeners introducing native plants into their gardens, the concept of invasiveness is completely subjective. Many local native plants that have to battle for survival in a wild property next door can grow rampantly in a cultivated garden. Although it is neither noxious nor invasive, I have spent several days lately pulling up literally hundreds of Miner's Lettuce (Claytonia perfoliata). Achillea millefolium on the other hand is so far very well behaved.
     
  5. raingarden

    raingarden New Member

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    Interesting, I'm not sure that I've seen miner's lettuce before, but I just started looking into this over the winter. Technically by law I was reading that it isn't completely subjective. If the plant is on the list of regulated noxious weeds, it must be disposed of from a home garden into a trash can, or chemically controlled. However, I don't imagine that most home gardeners are aware of these laws (or able to distinguish every species when there are sometimes hundreds of similar ones), and the presumption by those who enforce them may be that most people would pull all the weeds as a convention anyway.

    So far I've only pulled up some Senecio vulgaris (ground swallowers) for that reason, but I doubt I'd ever find them all (hiding under other plants and such, which seems to be how a lot of these weeds are designed to grow—I was looking at how some of their stems are thin, yet spaced fare apart for that, or with dandelions, how their leaves can articulate like arms and stick up through a small shrub or the tall grass of course). I'm leaving the dandelions alone for the most part though, because I'd rather they take up any space that the groundsels might occupy otherwise (and this noxious one is also poisonous). Besides, it seems that the more plants I dig up, the more the soil is disturbed, and this only causes more plants to grow (I swear, for every one removed, two or more will replace it)! Ha, I wouldn't necessarily complain about that, because I hadn't realized it could be so simple to have a green thumb, at least in a temparate climate (just kick some dirt around and wait)... next thing you know, you'll be stepping on a bunch of seedlings.

    I don't know if that's ironic, but there may be more native species pulled up as weeds than anything else. Well I only know about a handful of them so far, but here's another resource I found out about:

    USDA Forest Service Pacific Northwest Related Links
    Region 6 - Plants
     
    Last edited: Apr 28, 2020
  6. Margot

    Margot Renowned Contributor 10 Years

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    Under BC's Weed Control Act, there is a "duty to control noxious weeds" which would seem to be seldom enforced. In a city closeby, a 6-acre parcel of vacant land was allowed to harbour both Scotch broom and gorse for at least 30 years and is only now being cleared for development.

    Duty to control noxious weeds

    2 In accordance with the regulations, an occupier must control noxious weeds growing or located on land and premises, and on any other property located on land and premises, occupied by that person.

    Weed Control Act

    Thank you for the informative links you've provided, raingarden.
     
  7. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    Well, here's how I define the terms in my head, for what it's worth. These are all situational definitions:

    Invasive: an introduced species (or genotype) that is harmful to local wild biodiversity, typically through displacement or predation

    Noxious: a species that may cause agricultural harm that is regulated by provincial or municipal legislation in order to permit enforcement of eradication, fines, etc.

    Aggressive: a species in a gardening situation that resists the methods employed by the gardener to eradicate or control
     
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  8. wcutler

    wcutler Paragon of Plants Forums Moderator VCBF Cherry Scout 10 Years

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    Yes you were, and this conversation in the Resources discussion thread is driving me crazy. This thread is about what books and websites to add to the Pacific Northwest Native Plants Resources page, and that's not an area that people generally read. So I want to move all the discussion beginning with posting number 4 into its own thread in - well, that's my problem. Does it belong in the Pacific Northwest Native Plants forum or the Plants: Conservation forum, which says it's the place to discuss invasive plants. And someone could suggest a subject line, please.
     
  9. raingarden

    raingarden New Member

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    I find this humorous, because gardening and such is all about moving plants around, but then, so is talking about it ('let's just move this happy little hybridizing tree of a subject right over here, and put a new sign on it, like in a botanical garden'). Did I say something invasive? Well I beg your pardon, but the last link to the forest service page does the same thing (mentioning both botanical and invasive sites under the same topic of Pacific Northwest plant resources). So it isn't just me. Well I'm not arguing for you to reorgainize it this way, just saying (I happened to be thinking about it this way so it was merely my perspective at the time).
     
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  10. Margot

    Margot Renowned Contributor 10 Years

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    No, I am also guilty of going off-tangent. It's just that the subject of invasive/noxious/aggressive plants is much more engaging than a discussion on Resources.

    Sorry.
     
  11. raingarden

    raingarden New Member

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    Thank you too, I wonder if the particular location of those determines if they bother to enforce the regulations, or if someone has to complain. Like if it is spreading into a nearby natural habitat. It seems like a lot of the introduced invasive plants are from Europe, and that's far enough away that birds may not propogate them, so maybe they don't propogate those kinds very far from a city (although I've read that some seeds can be dispersed by the tires of vehicles taking them for a ride). Around here, I've noticed that the wild plants that have been weed whacked and go flying through the air end up growing across the street from there... maybe they could eventually travel for miles that way, if every area that they subsequently grew in got weed whacked also.
     
  12. Daniel Mosquin

    Daniel Mosquin Paragon of Plants UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    A cynic (a realist?) might say that weed control acts were put in place so that neighbouring farmers could force an offending farmer to take action to do weed control (and thereby reduce economic harm to them). This is similar to lawn care ordinances in many cities, though these are mostly to enforce a particular kind of aesthetic.
     
  13. raingarden

    raingarden New Member

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    Actually there are various online publications in WA. I was mainly interested in those relative to landscaping (erosion being a side-effect of some weeds for instance), and the Weed Control Board has several presentations which explain that they want everyone to understand the problems surrounding legally defined weeds, beyond it being some kind of obscure law. However, in other departments, publications for low impact development say that non-native species are recommended along with native ones to solve the same problems, often related to urban stormwater runoff from impermeable surfaces, and watering those plants (instead of sending it all into the sewer) will filter contaminants, or prevent flooding, in order to improve the environment... so look, either taking away some non-native species or adding others may be related to an environmental problem or solution. Then again, I've also read that some of the noxious weeds may have been introduced to solve another kind of problem in the past (and then they became the bigger problem).

    Noxious Weeds in Washington:

    "Once established, these aggressive plants colonize our croplands, rangelands, forests, wetlands, and water ways, causing economic and ecological damage that affects us all in Washington. That’s why everyone- homeowners, outdoor enthusiasts, farmers, and public land managers - have a role to play in the effort to control and prevent the spread of noxious weeds."
    Washington State Noxious Weed Control Board (Publications)


    Rain Garden Handbook for Western Washington, Appendix-A Plant List:

    "The plant list on the following pages includes native and non-native plant species and varieties suitable for rain gardens and commonly available in western Washington."
    Rain Garden Handbook for Western Washington: A Guide for Design, Installation, and Maintenance


    Eastern Washington Low Impact Development Guidance Manual, Appendix-D Bioretention Plant List:

    "This appendix is intended to provide guidance for the selection of trees, shrubs, grasses, perennials, wildflowers, and groundcover for bioretention facilities. The plant list contains both native and non-native species that are well suited for bioretention planting."
    Eastern Washington Low Impact Development Guidance Manual

    By the way, I wasn't technically interested in bioretention facilities in Eastern WA, it just so happened that when I was looking up whether a Stanleya pinnata (prince's plume) plant was a native species here, the bioretention plant list said it was a native species (yet it was something I saw initially on the Pacific Northwest Wildflowers site—which maps it as being native to southeastern Oregon, and northern California)... Whatever, but it may be used for phytoremediation as a selenium hyperaccumulator. Yes!

    Now, does it get any more obscure than that?
     
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  14. Margot

    Margot Renowned Contributor 10 Years

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    If you have time, I'd like to know more about how erosion can be a side-effect of some weeds.
     
  15. raingarden

    raingarden New Member

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    It was just that some of them don't prevent erosion with their root systems as well as the native plants that they take over the landscape of by being noxious or invasive that way. I don't remember which plants at the moment though...

    Alright, I looked it up on the weed control board this time, and they have a long list actually (it's like a typical attribute of the noxious weeds listed there). Another reason they give is an invasive plant dying back seasonally, whereas the native one wouldn't.
     
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  16. Margot

    Margot Renowned Contributor 10 Years

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    Ah, reminds me of long -ago lessons about sins of omission and sins of commission . . . applicable to weeds which offend as much by what they do not do as what else they do. Double whammy.
     
  17. raingarden

    raingarden New Member

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    Oh yeah, proverbially this may be similar to not identifying the noxious weeds too, and I think the information on seedlings could be better for that matter, because they say it is best to control them at that stage of development, yet they don't really have very detailed photos of those at different stages of development, if any.

    We might presume that they'd like us to pull up all plants that weren't put there intentionally, based on knowing what they were in the first place, yet this State (at least) is also promoting 'bee gardens' by allowing the wildflowers to flourish, in order to save the bees, so it may cause more harm than good to simply pull up all the mystery plants, before confirming that they are in fact harmful to the environment in some other way, because bees are supposedly an essential part of the ecosystem, and they need more plants to be growing.

    I've written enough about this though, there are invasive typos sprouting up in my textarea here (and I know I didn't type them)...
     
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  18. Louis A

    Louis A Member

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    I can tell I'm jumping in to a hot topic here. So let me start by clearly stating that I have certain plant biases. While one of my favourite trees of all time, artctostaphylos, is a native, I tend to grow some non-native (to the PNW) varieties because some are actually better adapted to the city garden. Additionally, I have an affinity for desert plants such as agave and yucca. Throw a few grevillea and salvia into the mix and I quickly hear "that doesn't belong here." Strictly speaking, no, you're right. But from my observations, none are invasive and they have encouraged and supported a wide variety of wildlife - namely hummingbirds and bees. What I'm getting to is that I fear judgments come down on non-native plants strictly due to appearance sometimes. That is by no means a broad sweeping statement, but I have experienced it. Maybe it's inexperienced native plant types, but I often see a host of non-natives adorning landscapes that are not subject to the criticism.

    But on the subject of plant "thugs," Aegopodium podagraria was in the garden before we got here and is a nasty thug to try and eradicate. Even some plants that I love I have "rid" the garden of - though I keep finding them. Nassella tenuissima, and euphorbia characias wulfenii come to mind. I got lazy once with cutting both those plants back and have them by the hundreds in the garden. It's actually impressive. So to the compost pile they went. I've heard of others saying that mexican feather grass isn't bad for their gardens, but it certainly likes the conditions in mine - And it certainly makes me sad that I had to get rid of it.
     
  19. Margot

    Margot Renowned Contributor 10 Years

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    I grow dozens of plants native to coastal BC because I think they are beautiful and because many of them already grow on or near my property - mainly bulbs, groundcovers and ferns but also Garry Oak and Arbutus. At the same time, I have spent years trying to rid the place of non-native, invasive plants such as bur chervil, euphorbia, tansy, Daphne laureola and many grasses that take up valuable space. But I could never relegate myself to native plants only - partly because native perennials often start to look scruffy by summertime but mainly because there are just so many beautiful plants in the world and I don't care where they originate.

    Read what Linda Chalker-Scott has to say about native plant 'superiority'. https://s3.wp.wsu.edu/uploads/sites/403/2015/03/native-plants.pdf

    She has co-authored a new book, "Gardening with Native Plants of the Pacific Northwest".
    “Here’s an important point to understand. Many of today’s non-native cultivars are also great plants for pollinators. So my perennials, trees and shrubs have within them the genes of their original natives, and they, too, produce flowers, seeds and berries important to wildlife.” Linda Chalker-Scott

    You have to draw a line though - beneficial as blackberries may be for wildlife, no one wants it in a garden.
     
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