[APWG] Jewelweed

Tue Jul 19 17:08:06 CDT 2011

Hi Sasha and everyone,

Thank you all for the information and discussion!

This plant has a large horizontal spur, nearly 1/3 the length of the rest of
the flower. It has spots that are detactable (a bit paler than the
background color) when viewed from the side of the flower, and some that are
quite evident when viewed looking into the flower.

Photos of the flower taken on site appear more orange in color than the
dried flower.

I got involved in trying to figure this out when a friend who, or is a
long-time wildlife manager here noticed it for the first time, and had never
seen it before in the southern Idaho area. Nor had I. He had run into a dead
end figuring it out before it flowered. Meanwhile a pond area was filling up
with the plant. Then finally it began flowering this week.

I will track down Peter Zika¹s article since this is indeed complicated ....

Katie

On 7/19/11 2:48 PM, "Shaw, Sasha" <Sasha.Shaw at kingcounty.gov> wrote:

> Katie, are you sure of the species?  There are Impatiens species similar to I.
> capensis with yellow and orange flowers that are native to the western US.
> I¹m not very familiar with the ones not found out here on the coast, but Peter
> Zika¹s article on the new hybrid (referenced in Dominic¹s email below) has a
> good key to Impatiens in the Pacific Northwest.  Look especially at I.
> parviflora and I. aurella as well as I. ecalcarata that Dominic mentions
> below.  We also had confusion here with a yellow flowered species called I.
> noli tangere, which I believe is just found on the northwest coast of the US
> and Canada.  When we were trying to determine what species we had here in
> western WA, I felt fortunate that we weren¹t east of the Cascades, because it
> gets more confusing over there with more native Impatiens with orange and
> yellow flowers.  
>  
> I¹ve been following the discussion and research about I. capensis with
> interest.  In King County, WA we list it as a Weed of Concern because it does
> invade pretty pristine areas that otherwise mostly have native species and
> because it does at times grow very densely and could perhaps impact other
> riparian herbaceous species.  It also certainly takes advantage of disturbance
> and openings quite easily and quickly and seems to persist and become more
> abundant over time.  Also, Peter Zika¹s research found that it apparently is
> attracting pollinators away from our much less common native I. ecalcarata
> (spurless jewelweed) which has less nectar.  Both the new hybrid and I.
> capensis have more nectar and attract more pollinators. This means the seed
> set of the native I. ecalcarata is reduced.  He found that the range of the I.
> ecalcarata is declining and I. capensis and the hybrid are increasing, perhaps
> due to this issue or to being less competitive.  This seems reason enough to
> call I. capensis a problem on the west coast.  However, it is not nearly as
> bad a problem here as I. glandulifera, which is much more aggressive and
> dominates sites much more.  I¹m not sure if it makes sense to chase down I.
> capensis everywhere, but probably it should be prevented from spreading more
> into our more remote areas where it is starting to encroach.
>  
> One caution about removing I. capensis in our region (the Pacific Northwest)
> is that it can¹t be safely distinguished from I. ecalcarata and the hybrid
> until it is in flower.  Generally speaking the I. ecalcarata flowers are
> orange, don¹t have spurs and don¹t have any spotting.  I. capensis and the
> hybrids all have either spurs, spots, or both.  Again, I would refer folks to
> the Zika articles for more info and an accurate key.
>  
> Also, as a comment on other posts on this plant, I agree that it is important
> to distinguish between mostly ruderal or opportunistic non-native plant
> species (weeds) and those non-natives that are truly invasive and able to
> escape into and thrive in ecosystems in their new location at the expense of
> the species that are native to that ecosystem (invasive weeds or invasive
> plants). It¹s not always easy and there is certainly a lot of overlap between
> the groups, but we do need to prioritize so we can focus on the species that
> could cause the most harm if they were ignored.  That said, it¹s not always
> obvious which species are going to cross that line to becoming invasive
> instead of just opportunistic.
>  
> Most introduced species start showing their weediness in disturbed areas first
> and we want to act quickly before new invaders get entrenched, so when do we
> know for sure how much harm a species could cause (but before it has done that
> harm and it¹s too late to stop it)?  How do we act early enough to be
> effective, but not over-react to all non-native plants?  In our county, we
> look for introduced plants that have shown up where they were not planted and
> that have reproduced successfully and are thriving, apparently at the expense
> of native plants.  At that point, it seems to me it would be wise to take
> action to stop its spread.
>  
> 
> <<>><<>><<>><<>><<>><<>><<>><<>>
> Sasha Shaw
> King County Noxious Weed Control Program
> 201 S. Jackson St., Suite 600
> Seattle WA 98104
> 206-263-6468
> sasha.shaw at kingcounty.gov <mailto:sasha.shaw at kingcounty.gov>
> www.kingcounty.gov/weeds <http://www.kingcounty.gov/weeds>
> 
> From: apwg-bounces at lists.plantconservation.org
> [mailto:apwg-bounces at lists.plantconservation.org] On Behalf Of Maze, Dominic
> Sent: Tuesday, July 19, 2011 8:42 AM
> To: 'Katie Fite'; apwg at lists.plantconservation.org
> Subject: Re: [APWG] Jewelweed
>  
> Hi Katie et alia,
>    Impatiens capensis is, in my experience, a problematic species here west of
> the Cascade Range in the Pacific NW.  The densities of this sp. are pretty
> amazing with the understory of riparian corridors often dominated by it.  I¹ve
> been seeing more and more of it in the Willamette Valley and surrounding
> ranges here in Oregon with seemingly little attention paid to it.
>    Interestingly, some land managers still consider this species native here
> on the West Coast, probably due to confusion with our native, I. ecalcarata in
> some older floras and field guides.  Ed Alverson of TNC wrote a short comment
> in reply to a posting on I. capensis at the Botany Photo of the Day website:
>  
> ³Impatiens capensis is an introduced and invasive species in the Pacific
> Northwest, west of the Cascades. Peter Zika addressed this issue in a 2006
> paper, "The status of Impatiens capensis (Balsaminaceae) on the
> Pacific Northwest coast", published in the Journal of the Torrey Botanical
> Club, vol. 133 pp. 593-600. In fact, I. capensis is spreading into the
> habitats of the uncommon native I. ecalcarata west of the Cascades, and the
> two species are hybridizing. This has created a situation where the native
> species is potentially being out-competed by both the introduced species and
> by their hybrids. Zika has published another paper on the hybrid, which he has
> named Impatiens x pacifica, see "Impatiens x pacifica (Balsaminaceae), a New
> Hybrid jewelweed from the Pacific Northwest Coast of North America", Novon
> vol. 16, pp. 443-448, 2006.²
>  
> Add this spp. to I. glandulifera (a big problem) and I. balfourii (an escaping
> species which may be a problem in the future), and we¹ve got our hands full
> out here with the touch-me-nots.
>  
>  
> 
> Dominic Maze | Invasive Species Coordinator
> City of Portland Environmental Services
> 1120 SW 5th Avenue, Room 1000
> Portland, Oregon 97204
> p:  (503) 823-4899
> f:   (503) 823-5344
> dominic.maze at portlandoregon.gov
> 
> 
> From: apwg-bounces at lists.plantconservation.org
> [mailto:apwg-bounces at lists.plantconservation.org] On Behalf Of Katie Fite
> Sent: Monday, July 18, 2011 5:46 PM
> To: apwg at lists.plantconservation.org
> Subject: [APWG] Jewelweed
>  
> 
> Has anyone had any experience with jewelweed (Impatiens) native to the eastern
> U. S. becoming weedy in valley marsh habitats in the intermountain West?
> 
> I see that jewelweed Impatiens capensis (orange jewelweed) is listed as a King
> County  (WA) ³Weed of Concern².
> 
> This species is shown as having a yellow flowered form, which is what we are
> seeing.
> 
> http://www.kingcounty.gov/environment/animalsAndPlants/noxious-weeds/laws/list
> .aspx
> 
> Katie Fite
> Western Watersheds Project
> katie at westernwatersheds.org
> 
>   
> 

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