I guess the lythrum will have to go

marciaz3 Tropical 3 Northwestern OntarioAugust 9, 2005

I spoke to a friend who is a former biology professor last night and his advice was to get rid of the lythrum. :( It's really pretty and the bees love it, so this is a difficult thing to do. My fault for not researching what it was, but if a place like Dominion Seed House is selling it, you would think that it's okay to grow. At least i did. I should have checked into it more when people here mentioned that it shouldn't be sold.

Sigh... I don't want to be responsible for choking out NWO's wetlands! Heck, that would be my own back yard!

Thank you for reporting this comment. Undo
dentaybow(Z3A MN)

Marcia- I remember your post when you purchased this Lythrum. If I recall correctly it was a Terra Nova thing. The U of MN had a blurb about it too....but it is my impression the U and Terra Nova are joined at the hip so I kinda wondered about their comments. I can't remember the named variety of your purchase. Would you mind checking the tag and re-posting the variety/name? I want to re-do my research on this lythrum. Some of the newer cultivars are said to be sterile...but some sources say they occasionally produce seed and/or cross with other lythrum species.
I wouldn't put a whole lot of credence in a reputable nursery selling a plant that may be invasive or noxious. It happens all the time. White Flower Farm on this side sold Purple Loosestrife until just a few years ago. They just boldly proclaimed they didn't think it was invasive or a problem in wetlands.
Incidentally, I think destroying it is a wise thing. I am paranoid about this genus....and my backyard is close to your backyard. :(

    Bookmark   August 9, 2005 at 8:52AM
Thank you for reporting this comment. Undo
marciaz3 Tropical 3 Northwestern Ontario

Jan, it's Lythrum X. Terra Nova. Dominion Seed House says this:

"It's the least fertile among all the cultivars tested by the University of Minnesota. 'Terra Nova' is a dwarf variety and will not spread all over the gard. Pretty, deep pink flowers. Much imporved variety in comparison with the other varieties! Does not sucker."

So it's the "least fertile", not sterile. I don't think there's any wild loosestrife around here but there is in Thunder Bay, and it will probably move west on its own even though there are efforts underway to eradicate it.

I winter-sowed some pink digitalis this year, so maybe that will fill the empty spot.

    Bookmark   August 9, 2005 at 9:00AM
Thank you for reporting this comment. Undo
Crazy_Gardener(Z2b AB Canada)

Marcia, I too have been growing Lythrum X Terra Nova which I ordered years ago from Dominion Seed House.

In all these years I have not seen it run wild, I also make sure that I cut the blooms down right after they have finished blooming before it has a chance to set seed.

Could you please ask your biology friend if this is still acceptable, otherwise I will get the roundup too.


    Bookmark   August 9, 2005 at 3:08PM
Thank you for reporting this comment. Undo
marciaz3 Tropical 3 Northwestern Ontario

Okay, i'll ask him when i see him on Saturday. I haven't had the heart to pull it out, actually. The bees love it so much and there's always a few on the bigger plant. DSH says it doesn't sucker - is that your experience too?

    Bookmark   August 9, 2005 at 4:46PM
Thank you for reporting this comment. Undo
Crazy_Gardener(Z2b AB Canada)

It spreads a little, but not wild & fast, I have never divided it.

    Bookmark   August 9, 2005 at 5:54PM
Thank you for reporting this comment. Undo
dentaybow(Z3A MN)

Thanks for the name of the Lythrum, Marcia.

I did some googling. Could find almost zip specifically about the Terra Nova cross except what you quoted. But....I did read a lot of really interesting things related to the garden crosses.

I get my jollies from horticultural research...some may want to quit reading now....it is going to get boring.

In the early 90's, after Lythrum salicaria (Purple Loosestrife) had seriously invaded many waterways and wetlands, some states (including Minnesota) passed legislation to totally ban all species of Lythrum and all cultivars. At that time, many cultivars had already been developed for garden use. Even Morden had developed several cultivars/crosses. It was thought that these cultivars were either sterile or would not cross with the invader. Big controversy ensued. Why ban the cultivars if they were sterile, etc? So....Neil Anderson, Horticulturist at the U of MN did a major research project to prove or disapprove the sterility of cultivars. Here is a quote from the conclusion in his research abstract.
"This study showed that the cultivars are highly fertile when used as male or female parents with wild purple loosestrife, native species (L. alatum Pursh.), or other cultivars. Thus, cultivars grown in gardens could serve as pollen or seed sources for the continued spread of purple loosestrife."

University of Manitoba has also done several studies on this same issue. Here is a quote from their research.
"Manitoba Horticultural cultivars of purple loosestrife (Lythrum spp.) were developed in the mid- 1900s for use as a garden and landscape ornamentals (Harp and Collicutt, 1967). These cultivars initially were thought to be sterile and, thus, safe for horticultural use. Recently, Ottenbreit reported that artificial crosses between 'Morden Pink', 'Morden Gleam' (L. alatum Pursh x L. virgatum), and wild L. salicaria produced hybrid plants that were highly fertile. Further, Anderson and Ascher demonstrated that these cultivars are highly fertile when crossed with L. salicaria, L. alatum, or other cultivars. The authors of both of these papers concluded that purple loosestrife cultivars grown in gardens could serve as a pollen or seed source contributing to the spread of purple loosestrife in natural areas".

More interesting stuff out of Manitoba research.
"Literature on this topic has supported the concept of "good" (garden type) lythrum, and "bad" (noxious weed ) lythrum. Our study of floral and vegetative characteristics now reveal that there is no consistent difference between the weed established in a wetland habitat and garden lythrum offered for sale and grown in gardens. Examination of lythrums from a local infested wetland revealed a wide range of morphological characteristics, including size and color of petals, density of inflorescence, pubescence, alternate/opposite leaves, and so on. In other words, given the right conditions, any of the "garden type" lythrums could become established as a serious pest."

From Alberta:
"Gardeners have been led to believe that L. virgatum (a species not specifically included in the Alberta Noxious Weeds Act) would provide a suitable alternative to L. salicaria. Unfortunately these two species hybridize readily, making L. virgatum a part of the problem. Neil Anderson and Peter Ascher in their paper Male and Female fertility of loosestrife (Lythrum) cultivars, observe "...L. salicaria and L. virgatum...have both colonized wetland habitats, frequently becoming monospecific stands. These two species are considered by North American taxonomists to be the same, since they differ only by a few minor diagnostic characteristics and intercross freely."

More from Alberta:
"Much of the loosestrife literature mentions the existence of sterile selections--specifically 'Morden Pink'--that presumably would not produce seed, and would therefore pose no threat to wetland habitats. None of the loosestrife complex, however, are "safe". 'Morden Pink' is not the sterile plant that it has been claimed to be, and is, in fact, a parent of numerous selections including 'Morden Gleam' and 'Morden Rose'. A cross-pollination study out of the University of Manitoba concluded that lythrum cultivars may contribute significantly to the problem of the naturalization of purple loosestrife in this continent."

End of all quotes:
Has anyone made it to the end? Is that snoring I hear? I will creep quietly away in an attempt to not wake anyone.

    Bookmark   August 9, 2005 at 6:25PM
Thank you for reporting this comment. Undo
northspruce(z3a MB CDA)

No snoring here Jan, your research is always appreciated. Or maybe I'm just a geek too :)

I don't have loostrife of any type and now I will continue to avoid it. I figure when it comes to the environment it's better to err on the side of caution. There are some things you just can't undo however well meaning it started out.

Thanks for the heads up Marcia.

    Bookmark   August 9, 2005 at 9:11PM
Thank you for reporting this comment. Undo


Lythrum X Terra Nova is not invasive on it's own, the issue is that it could potentially cross with a wild Lythrum salicaria and produce seed.

As a correction, Terra Nova Nurseries has absolutely nothing to do with Lythrum x Terra Nova. The reason it is called that way is because it was discovered by T. Huber in "Terre Neuve" which is french for Newfoundland. It is considered to be 'almost' completely sterile.

    Bookmark   August 9, 2005 at 10:02PM
Thank you for reporting this comment. Undo
Crazy_Gardener(Z2b AB Canada)

Marilena, thanks for your expertise ;)

So, the question is now....do you suppose it would be passable to grow TN if one was to faithfully cut off spent flowers before the plant can set seed just incase they do cross pollinate with L. salicaria that are growing wild in the proximity?


    Bookmark   August 9, 2005 at 10:51PM
Thank you for reporting this comment. Undo
marciaz3 Tropical 3 Northwestern Ontario

I'm really torn! As far as i know, there is no wild loosestrife around here, but there is some 250 miles away in Thunder Bay. Perhaps if i make sure it's deadheaded, like Sharon does, i could keep it. But on the other hand, if there actually IS loosestrife around here, i don't want the cross-pollination to occur.

I think i will contact the Biology or Forestry Dept. of Lakehead University and see what they say. Someone there is sure to know how far west purple loosestrife grows.

What a dilemma! I'm ticked off at Dominion Seed House for selling it and not properly identifying it! (and maybe at myself for not researching it - but i seldom ever do, just buy something if i like it).

    Bookmark   August 9, 2005 at 10:57PM
Thank you for reporting this comment. Undo
abgardeneer(Z3, Calgary)

The problem, as extremely well and thoroughly set out in Jan's explanation, is two-fold:
These "sterile" lythrum garden cultivars have been known for a long time to be capable of providing pollen to populations of lythrum that have escaped into the wetlands, which then, happy to get an injection of slightly different genetics, set seed and spread further. Secondly, your supposedly sterile garden cultivar may in fact be capable of producing seed itself.
So, deadheading your flowers would presumably take care of the second possibility, but not the first.
I'd echo the previous posters in saying that the only responsible approach is simply to not grow lythrum.

As I remember mentioning when this thread first came up last year, I'm really amazed that a large plant dealer could get away with selling noxious weeds, and perhaps even more that they would dare to.

    Bookmark   August 9, 2005 at 11:19PM
Thank you for reporting this comment. Undo

My husband loves Lythrum and years ago I forced him to remove it (I had the Morden hybrids) as the plants were setting seed. I think Lythrum salicaria and many of the hybrids are weedy. Since I don't like weedy plants to begin with, I wouldn't keep them in my own garden.

If you go to Eastern and Southern Ontario you will see massive amounts of Lythrum growing everywhere. It is all over the ditches at our place in Ottawa and although we mow it down, our neighbors do not.

Nobody really knows if Lythrum salicaria is destroying the wetlands since the research is not conclusive. Art Drysdale, a noted author and horticulturist has argued this point and does not believe that it is invasive.

Have a look at either of these 2 articles for more info:


Why would Dominion Seed sell that Lythrum you ask? T. Huber or Tony Huber who discovered the plant works as a breeder for Norseco located in Laval, Quebec. Norseco owns Dominion Seed also known as Horticlub in Quebec.


    Bookmark   August 10, 2005 at 12:06AM
Thank you for reporting this comment. Undo
dentaybow(Z3A MN)

Thank you, Marilena, for the info on the origin of Lythrum X Terra Nova. Explains why so many of my Google hits were French language sites. However, it did make me wonder even more why the quote from Univ. of MN is associated with this plant.....has overtones of the U of MN promoting this cultivar. Having given it some thought....I suspect it is because Neil Anderson (or cohort) is still doing testing on the various commercial cultivars of Lythrum. Perhaps the plant description info uses the 'least fertile' from Anderson's findings followed by promo info of their own? Unfortunately, it makes it sound like the Univ. of MN advocates this cultivar. I am probably being parochial here, but I don't like it one bit! Guess I will have to contact Dr. Anderson and ask him. He is one of those neat researchers who is great at interacting with the public and teaching.

You make a good point concerning the 'other side' of the controversy. There are advocates for invasive species and some are real activists. Some of the activists promoting this school of thought tend to equate the introduction of plant invasive species with the much earlier European migration of humans to this continent. i.e. the plants have as much right to migrate to this continent as our ancestors did. I will never forget, when I first came to the GardenWeb forums, a thread on Lythrum on the Perennial Forum. To say it was vicious is a major understatement. I was horrified to be called a racist and worse. Things degenerated from there and Spike pulled the thread. So....yes, in some arenas introduced invasive species is a definitely a 'Hot Button' topic.

    Bookmark   August 10, 2005 at 9:08AM
Thank you for reporting this comment. Undo
Crazy_Gardener(Z2b AB Canada)

Thanks for the links Marilena, I finally had a chance to read the whole article, Art has some good points!

    Bookmark   August 11, 2005 at 1:46AM
Thank you for reporting this comment. Undo
marciaz3 Tropical 3 Northwestern Ontario

Five year later update: I never got rid of the lythrum and it has never spread in all these years. I'm still on the lookout for the wild stuff, though, and have only seen one plant anywhere nearby (a mile or so away). Someone got rid of it before i could.

(I was going to bring up the Introduction thread and found this instead!)

    Bookmark   May 21, 2010 at 7:38AM
Thank you for reporting this comment. Undo

I have had two Mordens Pink in my flower beds for 15 years. They have not spread and are beautiful! I want to divide them, but I am so afraid of losing them that I keep putting it off. I think this great plant has gotten a bad name....maybe it was sold by some nurseries as Pink when in reality it was PURPLE. I also have the "Robert" plant in my side yard---but it looks more like a wild weed than a bush like the Mordens Pink. Great plant that blooms all season. I HATE that it cannot be purchased any longer.
My lythrun is STAYING!!!

    Bookmark   April 23, 2011 at 11:53PM
Thank you for reporting this comment. Undo
marciaz3 Tropical 3 Northwestern Ontario

Thanks for bringing this thread back, Linda. I was looking at the lythrum yesterday and thinking about how pretty it would be in a couple of months. I've re-read this thread, and i think that as long as there is no wild lythrum near here, i'll keep it. We have a large pond/dreek system in back that would be ideal for it and none has ever grown there.

    Bookmark   April 24, 2011 at 9:44AM
Sign Up to comment
More Discussions
Apricots in Flower
Capilano Apricot trees in Edmonton, picture from today. One...
Mature spruce with double leader
Hi everyone, I have a question that I can't find the...
Violetjune Zone 3
Austen's anyone?
I know Riki grows a lot of Austen's in zone 4. Anyone...
crabapple trees
The woodpeckers have done a real number on one of my...
Northland Crab apple
This is an older Mn. variety that is supposed to be...
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™