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dame’s rocket: asset, or invader?

dames-rocket-2bI WAS GOING TO SIMPLY NOTE TODAY how much I like the moment (now) when dame’s rocket, or Hesperis matronalis, blooms wherever it wishes among alliums and other late-May-and-June things, adding shades of lavender to the borders in its casual, self-sown manner. And then I read up on it (damn this internet thing…so much information, not all of it good).

It seems that dame’s rocket, a short-lived perennial and prodigious sower, is taking up more than its share of the natural spaces it spreads itself into (read: becoming invasive). In my area it is common along roadsides and woodland edges, in the filtered light of those spots, and really breathtaking at its peak. My plants blew in from across the road. But some states, such as Wisconsin, are noting its invasive tendency: the fact that it “escapes cultivation” so easily and takes up space that natives then must yield. Dame’s rocket has been on our shores since the 1600s, so it is no newcomer, but it is not a native American species, hailing from Eurasia. It’s often sold in “wildflower” seed mixes, and in packs by itself.

What do you think about our responsibility as gardeners when it comes to growing plants that are non-native, and this enthusiastic? It’s a subject I have a fair degree of knowledge about, having collaborated on “The Natural Habitat Garden” with Ken Druse some years ago and pondered many times since. Including just the other day on this blog when Highvalleygirl asked about some barberries I posted. Frankly, friends, despite my semi-expertise, I do not know the answer to this one. Tough stuff, and worth talking about (no fisticuffs, though, please).

dames-rocket

  1. Ouch, that’s a tough one. At what point does a plant win the right to be called “native”? How many centuries does it take to earn that coveted label? I’m a staunch defender of native plants, but I don’t believe we can stop all change. It depends, I suppose, at least in part on how much damage the invader does. Oh help.
    –kate

  2. Joy says:

    You have some gorgeous pictures on here ! .. Loved the morning light one .. awesome !
    I have grown Dame’s Rocket .. but had to move it out due to lack of room with my small gardens. Kingston has sown ditches and open areas with that plus natives .. and they do look amazing rather than just seeing greens weeds. I always notice them while driving by and think they look wonderful : )
    Joy

  3. Wow, it’s complicated. I guess one has to assess (and qualify) what “damage” it is doing and how extensive that damage is. Is it enough of an offense that it is a successful non-native plant that has a habit of springing up when and where it likes? Is there proof that native plants are feeling the pinch because of its presence? I don’t have an answer. Maybe it’s a matter of saying, “Time will tell?”

    At least it’s not as invasive as Purple Loose Strife, those beautiful spires of deep purple that are taking over marshlands all over North America.

    -Andrew

  4. Layanee says:

    What we have gained in this country with plant introductions may well outweigh the problems inherent within. If we consider everything native to the earth and introduce no extra terrestrial plant life forms could that suffice? Love the natives, love the exotics! Life here would be dull without tomatoes and broccoli to grow not to mention ornamentals!

  5. Dan Sealy says:

    Well, if it taking over out natural areas – not mention our gardens, we should refrain from planting it. Purple Loosestrife, English Ivy and bamboo all have wonderful attributes but if they endanger my native natural areas – let’s enjoy them in artwork and their native grounds.

    Ailanthus, one of the most invasive trees in the Eastern US has been here for hundreds of years, but it destroys American forests. Time in place does not qualify as native.

    We (Americans) spend hundreds of thousands of dollars and thousands of volunteer hours each year to keep invasive exotics out of natural areas including National Parks and nature preserves. Let’s do the right thing – it is not all about esthetics… natural biodiversity is important.
    Thanks for caring enough to post this.
    Dan

  6. margaret says:

    Welcome, Dan, to A Way to Garden. Lots to think about. I guess I want to believe we can garden with natives and well-behaved aliens, and frankly I never had any idea that Dame’s Rocket was considered anything but! So even a familiar, commonplace plant turns out to be somebody’s weed, as per the Wisconsin bulletin. Very interesting and provocative stuff.

  7. elizabeth says:

    after a recent trip through kentuckey and tennessee, i have been pondering this myself. i have lived in urban areas with beautiful, grown as specimen paulownia trees, but there they were scrambling among rocks, looking scraggly and taking up an alarming amount of space.
    i think avoiding invasive species is imperitive, because often it is out of human hands how quickly the seeds spread. and before planting something, it is good to check your states, and surrounding states list of invaders.
    (i do plant things that are not native…but fairly benign things, i think)

    i also find hybridized version of native plants worrysome. think of the recent wave of coneflowers in all sorts of subtropical colors. how certain are we that these will not cross breed and affect the natural population?

  8. Tim Abbott says:

    This is indeed a complicated subject, Margaret, and you have approached it with many of the right questions. I served for 6 years on the Massachusetts Invasive Plant Advisory Group, which included nursery & landscape professionals, scientists, academics, non profits and state agency staff. One of our most significant tasks was to develop objective criteria for assessing whether an introduced species should be considered invasive in the Commonwealth. You can read what I wrote about that process at http://greensleeves.typepad.com/berkshires/2006/01/born_of_a_shotg.html

    Many, certainly a large majority, of introduced organisms are not invasive. Those with the behaviors described in MIPAG’s assessment criteria often are. There are, of course, questions of degree, which for me come down to the vectors of spread, the difficulty and expense of control, and the implications of new invasions for biodiversity. Because Dame’s Rocket is wind dispersed, establishes itself in dense stand, and is particularly invasive in floodplains, it is listed as Invasive in Massachusetts. Rte 71 between Austerlitz, NY and Alford, MA along the Green River is a good example of what Dame’s Rocket infestations can become in our region.

    MIPAG’s process and criteria can be viewed at the following link: http://www.mass.gov/dfwele/dfw/nhesp/conservation/invasives/invasive_plant_info.htm

    Best wishes, Tim

  9. The Dame’s Rocket is just getting started around here, and I was wondering the same thing myself: what exactly makes something invasive? Why do I not feel (on my own land) that Dame’s Rocket is invasive, but multiflora rose is? They are both fragrant, both beautiful in bloom, but those thorns–does it make it easier to call the rose bad? Or is it truly more invasive? Or am I deceived about the Dame’s Rocket? And that native goldenrod I am struggling to eradicate from a garden bed, does it have to jump “the pond” before it’s invasive? It can take over a field as easily as the Dame’s Rocket.

  10. Rick says:

    Detrimental invasive for me is defined by a non-native plants who’s growth characteristics and reproductive habits become detrimental to indigenous plants. Many indigenous plants are invasive, but they are not so aggressive as to start to crowd out or desimate others within the local.
    Introduction of non-indigenous plants to other areas and locals that have resulted in a “Oh my God, what have we done…” result are legendary.

  11. diana says:

    I know here in the west there are some terrible invasives. Tamarisk(salt cedar,) for example is taking over some of the riparian corridors. It’s not just that it outcompetes the native cottonwoods and willows but it also concentrates salt in already saline soils to the point where nothing else will grow. This is detrimental to all species who rely on the natives. tamarisk is also a super water hog.

    In an urban area I wouldn’t worry about dames rocket. In fact, where I live I wouldn’t worry at all. I think you have to take it case by case but the class 1 & 2 invasives should not be planted where they can get any kind of foothold. Gardeners should bear some responsibility, if we don’t care, who will?

  12. Motyka says:

    Dame’s Rocket is invasive. And it is beautiful, with a light, almost jasmine scent. Which leads me to filling vase after vase with this “wild flower” from the ditches without the guilt of picking native plants.

  13. Pat on Jan. 1, 2009 says:

    Just discovered this site per Martha’s program today. What a treasure trove! Anyway, I LOVE Dame’s Rocket and for a while used it’s name as my email address. I have a new garden and last year cruised neighborhoods and roadsides looking for a new source for Rocket – and found one so abundant I can transplant new ones every year if needed.

    I am that weird gardener that simply loves all those so-called invasive plants. They keep me busy looking for them, thinning them, etc. I get a kick out of their pluck and the fact that they many are actually “wildflowers” -at least according to Peterson. (I believe it is in the same family as Joe Pye Weed.) Occasionally you will see a little patch in the wild, but rarely.

    Another favorite of mine is Hardy Ageratum, that just comes up everywhere. It had a banner year in my garden last year spreading its soft lavender everywhere among my taller perennials. I put it at the base of my New England asters, whole “legs” tend to look a bit scraggly. You can transplant this crazy thing even in full bloom in late summer and it doesn’t falter. It’s roots are very easy to hoe out where you don’t want it and are only a nuisance among ground covers. Gee, maybe I need to start my own blog – I am taking up a lot of space. Pat

    1. margaret says:

      Welcome, Pat. Thanks for starting the New Year off with us. I call plants like these “confidence-builders,” because they are so cooperative and energetic. Obviously critical for each of us to be responsible for our corner of the world, and it sounds as if you know when to pull out the hoe.

  14. Lisa says:

    Invasive or not, I think this plant is gorgeous, both in visual and aromatic terms. It’s definitely a keeper in any garden. I’ve found the trick to “maintaining control” over invasives such as bamboo, is to plant it in areas with appropriate boundaries….a grove of bamboo planted between the street and meandering concrete drive and walkways looks fantastic and when it drops its seeds, is cannot sprout! Wonder if container planting would work for rocket control?

    1. margaret says:

      Welcome, Lisa. I eliminate most of the seedlings in my beds, and just leave a few where I don’t;mind them. There are vast drifts of thousands of plants along roadsides here, so I am not going to ever be without it on my property no matter what I do (and I agree, it’s beautiful).

  15. I have dame’s rocket in the naturalized area around my silo (the only structure left over from when our place was a working farm). It grows under a stand of sumacs, and looks awfully pretty at this time of year. In the 11 years we have been on this property, I have not seen it anywhere else on our acreage, and it isn’t a problem in the surrounding lands. However, the invader that has increased quite a bit is garlic mustard. I go in among the dame’s rocket and sumac every spring several times to remove it. A decade ago garlic mustard was not in the woods behind my house, but now it’s taking hold there, and it has invaded all of the wooded areas at the golf course across the road from us. It’s the invader I’m concerned about. There is a lovely stand of red trillium and tiarella in the woods behind us, but I’ll bet the garlic mustard will wipe it out in no time. (I don’t have the energy to fight garlic mustard in the woods, and besides that land isn’t mine, although I walk there daily.)

  16. Janice says:

    It’s totally not cut and dried is it! I have the same issue with one of our native species deemed invasive by the Ministry of Agriculture — cow parsnips (a heracleum species). I love the way they look, and they are so well suited to growing here, but they seed like stink. I just finished writing my own musings on the same thing (http://www.naturechallenge.org/dmg09/janice/native_plants_friend_or_foe.html). Gardening certainly has its ups and downs, so I feel like if you find something you love, and it does well, why fight it! I do feel, however like I’m harbouring a fugitive!

  17. Bennie Catoe says:

    I love Dame’s Rocket and am planning to order seeds! In Zone 7, North Carolina I have Dame’s Rocket coming back from seed sthat I scattered around 1990! There isn’t much left – but still a bit. I love it. The afternoon fragrance is wonderful. I also love Lunaria Money Plant (or Honesty). It is first thing to bloom here in the spring and the purple with daffodils makes a great display. Some would consider it a pest also but the longer I garden the more I embrace the easier things that have made my garden home. Lamb’s Ear is another that self seeds everywhere – even in the lawn. Still loving your site. Thanks for your work!

  18. Siddhartha Banerjee says:

    I discovered Dame’s Rocket on Interstate 81 between Binghamton and Ithaca, NY, one of the most beautiful drives in the country. They grow, mile after mile, in dappled light under the edges of pines that line the highway. This year, I will put three of them in all their blue-purple glory into a clearing in the woods in front of my house. They can spread there without harm. The nearest beds are more than a hundred feet away.

    Thanks for a beautiful and infinitely interesting site.

    Siddhartha Banerjee
    Oxford, Pennsylvania

  19. I love your site; I heard about it on the Martha Stewart show and immediately looked you up. I’ve enjoyed reading about Dame’s Rocket today. I learned a lot that I didn’t know. Thanks for the enjoyable reading. Alice

    1. Margaret says:

      Thank you, Alice, and welcome! So nice of you to say hello. The dame’s rocket tides me over at the same time my alliums, perennial geraniums and so on bloom…so it’s a big, happy purple show. Don’t have the heart to tear it out. Oops!

  20. Melanie says:

    I live in the Binghamton/Ithaca, NY region spoken of above. I don’t mow until the Dame’s Rocket is done blossoming on one section of my lawn. It proves to be a lovely, frothy display year after year. The mowing nightmare and huge raking chore is worth it, to me.

  21. Andrew Keys says:

    I put my faith in the knowledge of folks like Tim Abbott (above) from MIPAG, who’ve devoted a lot more time and work to the subject than I’ll ever have! I can’t tell you how many gardeners have told me about their “well-behaved” burning bush that didn’t self-sow, because they didn’t notice the seedlings the birds had dispersed in the woods, which of course are the real problem. I also try to remember the mantra “First, do no harm” in terms of what I plant and let grow in my garden.

  22. Scarlett says:

    I have rocket all through my Canadian flower beds and I as much as I hate to pull a living plant out of the soil and have it succumb in my compost pile, I still much prefer my decades old peonies and roses — so most of the rocket come out to let the sun reach my peonies. But why oh why does it bother us to pull the rocket out and yet it’s so common to spend millions on damaging chemicals to erradicate dandelions? I think I like the pretty dandelions just as much as my rocket (but my neighbors give me such dirty looks).

  23. It’s not so much a native vs. alien issue, but one of environmental damage. Plants that harm the environment should not be encouraged. Many aliens plants are here to stay (Queen Anne’s Lace, chicory, dandelion etc).and have naturalized in ways that do not harm anything. The problem with some alien plants is that they change the wild landscape with a negative impact. Invasive plants ( barberry, burning bush, Norway maple, Asian honeysuckle) should be avoided by the gardener and removed from the environment when possible.

    1. Margaret says:

      Welcome, Diane. Yes, some aliens displace more desirable natives and that in turn affects habitat for wildlife and so on; a big, complex cycle of events to be sure.

      Welcome, Scarlett. I have to say I, too, am much stricter about no chemicals than about no aliens, but I do have some from my early years here that I wish I had never planted, and work to eradicate by digging and digging.

      A lot to think about; thanks for both your comments.

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