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Friend or Foe? Invasive plants, medicinal uses and Purple Loosestrife.

Updated: Jul 22, 2019

When I was driving home from work last night, I spotted one of my favorite upstate NY plants out of the corner of my eye: tall, bright pink and always in plain view, the appearance of Purple Loosestrife by the side of the road always reminds me that its now actually Summer. For real this time. This plant has been a close ally of mine since I started studying herbs and started getting to know the plants in this area - it was one of the first plants I saw on a plant walk, one of the first plants I gathered myself and one of the first plants I made successful formula with. We go way back, Loosestrife and I. I have always had a special place in my heart for this wildly pink lady who dots the fields pink through the late Summer months and looks extra pretty blooming next to the bright yellows of Goldenrod in August.

But not everyone feels like me. For herbalists and conservationists alike, Purple Loosestrife is one of those plants that we are not quite sure how to feel about. In New York State, Purple Loosestrife, like Japanese Knotweed and other commonly used herbs, is categorized as an invasive species. It has become so widespread that it is now responsible for “knocking out” populations of native species to this area, species that have been classified as endangered partially because of the influx of invasive plants to an already shrinking ecosystem. Unlike Goldenrod and many other less-threatening invasive European plants, Loosestrife does a better job of displacing other species, making it of particular concern.

The Cornell Cooperative Extension’s Division on NYS Invasive Species has this to say about it:

“Purple loosestrife is competitive and can rapidly displace native species if allowed to establish. Once established, the prolific seed production and dense canopy of purple loosestrife suppresses growth and regeneration of native plant communities. Monotypic stands of purple loosestrife may inhibit nesting by native waterfowl and other birds. Other aquatic wildlife, such as amphibians and turtles, may be similarly affected. The dense roots and stems trap sediments, raising the water table and reducing open waterways, which in turn may diminish the value of managed wetlands and impede water flow.”

Now before everyone gets upset and goes to light fires to their local loosestrife field, this is only half the story. The conversation on what, as herbalists, to do about invasive plant species has been ongoing and for me at least, there is never a clear answer. Some of the best medicines we have in our toolbox come from invasive species, brought over from Europe originally exactly for their medicinal properties. Loosestrife is no exception, and it does a great deal for us in terms of health and healing.

Here’s Purple Loosestrife from a plant medicine perspective:

Latin name: Lysimachia vulgaris

Family: Lythraceae

Part used: leaf and flowers (must be gathered when in flower)

Energetics: astringent, cold, bitter, stimulant, both moist and dry properties

Organ systems: intestines, kidneys, liver, lungs

Let's talk Energetics:

If you were to crumple up a leaf of loosestrife and taste it, you'd most likely react the same way you would if you did that with an unripe banana peel: that sort of sour, bitter taste mixed with your mouth feeling instantly dry and all your membranes tensing up. That is astringent - it sucks out moisture while at the same time giving tone and waking you up. The astringency of purple loosestrife makes it ideal for healing “flabby”, over relaxed tissue that has lost its ability to function due to excess moisture and/or loss of tone. The “stimulating” property is easy to see here as well, and I don’t mean nerve stimulant like cocaine or coffee - when we say stimulant in herbal energetics we mean arterial stimulant - it gets your blood moving!

So when might we want to use an herb like that? Anytime we've got tissue that is atrophied, full of fluid and blocked to the point where nothing can move like its supposed to. Like a sponge that is full of water and can’t do its job. To rebalance the system, the fluid must be expunged, the tissue must be re-tonified and the blockages must be moved.

This is the primary goal with inflammatory ailments like stomatitis, certain types of bleeding and vaginitis. Many kidney issues and some types of diarrhea and other GI conditions fit the bill as well. And since inflammation is a “hot” state, the “cold” properties of loosestrife help to calm the immune system which gets to the root of the issue.

But in my experience, nowhere does Purple Loosestrife shine like it does in sinus conditions. It is one of my top three favorite herbs for hay fever and allergic rhinitis, and it is up there on my list for sinus infections as well. In both of these, the sinuses become soupy, run down and full of mucus and fluid. The immune system is overactive and hot. The tissues can swell and cause blockages and breathing becomes difficult. The constant leaking of fluid causes irritation and dryness in some places (dry heat) and boggy grossness in other places (moist heat). Is it any wonder that Purple Loosestrife is the perfect plant to counter-balance all these conditions? It wrings out the boggy tissue, drains the fluid and moves it, shrinks the swelling, soothes the inflammation and gives tone back to the membranes. And leaves you feeling free and clear, which is the important part. Purple Loosestrife is one of three ingredients in my allergy formula tincture, along with Ragweed leaf (not flower, don't worry guys) and Nettle leaf. I also combine it with Goldenrod, Plantain, Goldenseal and Yerba Mansa in a nose drop formula for sinus infections.

So now that I've added my medicine plug for Purple Loosestrife, where does this leave our conversation about invasive plants? Do we rip it all out of the ground in an attempt to save our precious native plant populations, or do we lean in and ally with loosestrife in our healing pursuits? I am not sure I have a good answer to this question. In some ways, trying to figure out what to do with Purple Loosestrife is similar to trying to rectify our own footprint on the planet and the North American bioregion - neither we nor loosestrife are going anywhere anytime soon, and making the best of that situation is both honorable and worthwhile. But at the same time, acting with good conscience and with awareness towards the native ecosystem must be at both the forefront of our minds and our actions.

When considering invasive plant species:

-Do gather and use as healing medicine and food (when appropriate)

-Do be mindful of where you are gathering from (many invasive species grow near roadsides and buildings where exhaust and contaminates might add pollutants to the plants)

-Do work to protect native plant populations in your area - be careful when walking in the woods, when weeding gardens and camping. Learn about endangered plant species and where they live and grow. Protect these ecosystems.

-Do NOT plant in domestic gardens or in the wild

-Do NOT spread current wild populations to new locations or leave plants or plant parts in areas where they do not currently grow

And perhaps most importantly, do spread awareness of both invasive and native plant species so that as a collective we can continue to do our part to both gather responsible medicine and protect at risk species.

For more information about endangered plants in North America, check out United Plant Savers:

And to learn more about invasive plants in New York, here’s the link for the Cornell Cooperative Extension:

Looking to learn more about Loosestrife? Check out the following links from herbalist Jim McDonald in Michigan, and Henrietta’s Herbal:

If books are more your thing, I find Peter Holmes’ The Energetics of Western Herbs to be particularly helpful. Purple Loosestrife is in Volume 2!

Thanks for stopping by everyone! Happy gathering :)

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