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Is my catmint poisonous to my yard?
July 3, 2014 7:47 AM   Subscribe

Should I throw out the catmint I got from Lowes?

Per this and this and a whole bunch of other stuff.

I bought Walker's Low Nepeta about three weeks ago, four large plants that I cut in half - so I now have a ring of eight of these surrounding some blueberries. The blueberries aren't fruiting this year because I'm not letting them set fruit in order to get them to focus on growing up (they're second or third year plants).

We have a wooded yard and a lot of flowers, vegetables, and other plants. We use no pesticides or insecticides other than spraying ourselves with Off occasionally. I see a lot of bees, but now I'm paranoid I'm seeing fewer.

I also bought some August Moon hostas and four female hollies. I'm less worried about those because it seems like maybe those particular pesticides wouldn't have been used on them because they were not flowering.

I am willing to throw them all out if it's required to protect the ecosystem. I just genuinely can't figure out how alarmed to be.
posted by A Terrible Llama to Home & Garden (9 answers total)
 
Also please no finger wagglin' about my Lowe's buying! I already feel bad. I usually buy from a local garden center but was forcing myself to stick to a budget because I tend to go a little nuts with plants and just wanted to indulge myself in a bunch of crap. I just didn't realize how much 'crap' I was getting.
posted by A Terrible Llama at 7:51 AM on July 3


My understanding of the current research on bee colonies is population decline due to exposure to pesticides has three characteristics that make it less applicable to you. First, it occurs over a long time frame (more than three weeks). Second, it occurs more often in agricultural areas where pesticide use is much more prevalent than your garden. While the catmint was being grown, it was presumably exposed to pesticide, but so was all the ground around the catmint - perhaps only 10% of the pesticide actually ended up on the plant. That's certainly not good, but as a result, there is vastly more pesticide use where the catmint is grown (bad for bees) than in your garden (less bad for bees). Finally, research linking pesticide usage to colony decline is not universally accepted. To be honest, I'd find it hard to believe that four/eight plants could cause noticeable bee population change in your garden. If it was the case, then it would not be possible to use any pesticide-exposed plants in any garden of any size, which is not the case.

I think it'd make you feel better to get rid of them, though, so that might be worth it for you.
posted by saeculorum at 8:26 AM on July 3 [2 favorites]


Unless you specifically find a grower who is organic, recognize that almost all of your plant materials are going to have this issue. Commercial growers of Ornamentals aren't noted for being real concerned about pesticide use. You local guy is probably using a few similar vendors.
posted by JPD at 8:33 AM on July 3


Nepeta would be grown from cuttings in pots, not in the ground; it depends on the size of the nursery how the pesticide would be applied to the plants - some places would spray the plant directly while others might more or less spray the room.

I think that your best bet is to wash plants when you buy them - where the water that you use to wash them goes is, of course, something to think about. Your plants have been in the ground for three weeks so the rain has already done most of the washing.

You can't really assess how much neonicotinoids were/are in your plants.

I think that this is one of those things where you're just going to have to make a decision that has little to do with actual known information.
posted by sciencegeek at 8:35 AM on July 3


I don't know how alarmed you should be, but I recently attended a talk by Dr. Marla Spivak. One of the audience questions was about this issue--how do you find plants that haven't been treated with pesticides? The answer was to know your growers or grow plants yourself from organic seeds. I offer that mainly as comfort--here was an audience of bee enthusiasts faced with the same conundrum you are facing.

You could go back to Lowe's and ask if they know which pesticides your plants may have been treated with. My understanding is that most stores don't even know because the growers don't have to tell them either. If you do go back, here's a list of pesticide names that might be helpful.
posted by purple_bird at 9:41 AM on July 3


Washing is not likely to help with neonicotinoids, as part of the reason neonics are so useful is because they're taken up by the plant and distributed throughout its tissues (thereby hitting insects that chew roots, stems, leaves and flowers all at the same time): whatever's in there is probably not sitting on the surface waiting to be washed off anymore, if it ever was.

That being said, neonics don't remain in the plant forever, and if you bought the plants three weeks ago, my guess would be that they contain about half the pesticide they did when purchased. (Google is less specific than I would like, but what I found suggests that the half-life of imidacloprid, the most commonly-used neonic, is about a month once taken up by plants, about a month and a half in soil, and a few days in water.)

And for all you know there might have been no pesticide present when you bought the plants: the garden center where I used to work wasn't anti-pesticide by any stretch of the imagination, but the stuff outside on the nursery lots didn't get sprayed unless someone noticed that there was an insect problem, and even then, they tried to keep it minimal. (Not because they cared so much about the environment, but because the chemicals are too expensive to use when there wasn't an actual problem to fight.) A big wholesale plant producer might find it cost-effective to spray whether they noticed a problem or not, but they also probably don't ship the plants out immediately after treating them.

If it were me in this situation, I would keep the plants and just try not to buy pesticide-treated plants in the future, which it sounds like you were already doing anyway. Even if there is a harmful amount of pesticides in the plants, it's not permanent, and any damage you do to pollinators now is theoretically balanced by the benefit of having nectar and pollen available later.
posted by Spathe Cadet at 1:52 PM on July 3


Thanks everyone. You were more comforting than the Reddit thread I started with, which made me feel like I'd planted plutonium.

I'm just going to roll with it. It's an imperfect world. I throw things in the compost that are covered in pesticides, no doubt, and there are probably fertilizers etc coming through the stream, and there's probably something horrible in my shampoo, and meanwhile we'll all just do the best we can.

If someone comes along and says, with scientific evidence - or close -- that those plants will cause longstanding problems, I'll pull the plants and burn them.

If not, I'll try to believe in an overarching and inevitable equilibrium achieved by nature and the overall goodness of the ecosystem.
posted by A Terrible Llama at 4:51 PM on July 3 [1 favorite]


Hi! I used to be a commercial grower, working in huge greenhouses. I’m the one who rooted out thousands of tiny cuttings of Walker’s Low Nepeta, oversaw their planting into quarts and gallon pots, and then pinched, fertilized, watered, sprayed, and drenched them for months until shipping. These plants would head off to a nursery or garden center where they’d be priced and set out for sale. My commercial grower was too small to ship to a place like Home Depot or Lowes, but you betcha we used the same chemicals as the growers contracted with the big boys.

Growers use such toxic chemicals for several reasons. We know exactly how toxic they are, and don’t take any pleasure in using them. At my operation, we used them as minimally as possible, which came from multiple pressures, and also mimicked an industry-wide position. One, we sent detailed reports to governmental regulation agencies which required the record of every single application of every chemical – concentration, total amount used in each application, application method, etc. – because there are strict regulations governing each pesticide, fungicide and miticide. Second, the efficacy of any given chemical can decrease at a terrifying speed. Something sprayed one month could find a resistant population just months later. To be clear: there are no liberal applications of loads of chemicals “just because.” Companies who develop insecticides already find themselves behind the curve of resistance. Commercial growers need their pesticides to be effective. They grow thousands or millions of similar plants in tight quarters ideal for bugs; it’s a veritable buffet for pests who thrive on ornamental plants. If a pest population takes hold, which it can do in a matter of days due to the short breeding cycle of most of these insects, boosted by an average high greenhouse temperature, crops – and their enormous monetary value – can be completely ruined. My farm monitored extremely closely how often a chemical was used to reduce over usage. There are also lawful restrictions governing how often a single chemical can be used on a crop or in a given year, so we would have to weigh the severity of an infestation. Is this enough to “pull the trigger” on a certain chemical that we knew we could only use once or twice? Were we in danger of losing a greenhouse or a certain crop to insects? We would go out of business if so, and so we would carefully choose the least toxic chemical we could that would produce the desired, necessary pest control.

We also restricted our use because we knew these chemicals are toxic, and they are applied by people – our own employees, myself included – and had real effects. Many, many, many growers look increasingly to non-toxic forms of pest control. At my farm, we regularly used “beneficials” – insects that preyed on harmful populations. Despite our small size, we eagerly kept abreast of new research that explored better ways of suppressing or eliminating harmful pest infestations. We called it “feeding the chickens” because these “good” bugs would arrive in short cardboard tubes filled with grain and filler, and you’d break open the seal and shake it out over the canopy of a crop like chicken feed. We grew “banker plants” to establish populations of certain species of aphid which wouldn’t affect our ornamental crops. We’d then introduce a parasitic wasp which would feed on the aphid, lay its eggs inside the corpse, and let its progeny handle the other, nasty aphids which were feeding on our livelihood. These tactics are routinely used by the largest of growers. While terrible chemicals may never be eliminated, large commercial growers are also investing and using these tactics as standard business.

By the time the average consumer touches a plant for sale at their local gardening center or Lowes, it has been some time since a grower has used pesticides, fungicides, or miticides. One, a pest infestation is dealt with as soon as it’s detected, otherwise it will soon be out of control. This means it’s dealt with on plants too young to ship. Two, a grower doesn’t waste time pouring chemicals on something about to head out the door to be someone else’s problem. Why would we waste cost and labor on something that won’t be ours anymore? Three, we were extremely conscious of drenching or spraying a product close to shipping. Our customers, garden centers and nurseries, routinely asked about our chemical use and we would strike a balance between keeping our product alive, and keeping our product low-pesticide for commercial viability. Furthermore, there are strict laws governing a product’s REI, or return entry interval. On my farm, we used nothing with an REI over 24 hours (as in, drench it and don’t handle it for 24 hours), but larger commercial growers use things more toxic than this. We would be extremely conscious of treating shippable material: we took zero chances treating product likely to be shipped, but knew we couldn’t ship pest-ridden material.

This leads to another point, perhaps the most important. Growers use these insecticides, fungicides, and miticides because customers demand perfect-looking plants, despite also wanting pesticide/fungicide/miticide-free plants. In the last five/ten years, acceptance of organic vegetable and herb starts has exploded. As consumers, we have begun thinking about what chemicals we introduce into our bellies, yards, and communities. However, with an organic tomato plant, we only care about the final product: even if a tomato plant has speckled leaves, or some beetles, or what-have-you, no one cares as long as the plant produces edible tomatoes. With ornamental plants, their value is solely aesthetic. They must look perfect to be commercially viable. The problem is two-fold: a garden center would never accept a delivery of infested plants, or those showing pest damage even if the pest itself is gone, and a consumer, who likely knows absolutely nothing about plants, has an extremely unrealistic idea of what a living plant can and should look like. Plants are part of the living, broader eco-system, but plants grown for ornamental use are expected to exist outside such a sphere. Often plants have bug damage, but when the customer evaluates such damage, they are loathe to make a purchase. The garden center knows this, and brings these same demands to a grower, because otherwise they, too, would go out of business.

I managed a retail garden center for years, and frequently had customers point out a single, yellowed leaf and say “But what’s wrong? Why is it like this?” and I would always say, “We don’t look like Kate Upton, but we’re perfectly viable human beings. Plants are living things; they’re imperfect just like us.” This was an uphill battle. The same customer that would reject a tomato start because it had non-organic fertilizer would fill their wagon with ornamental perennials that had been undoubtedly drenched and sprayed with loads of terrible chemicals.

I don’t want to place blame directly on the consumer. Certainly growers can and should lead the charge to change to way ornamental plants look on the retail market. That said, allowing marginal pest damage is almost impossible in an environment that is ripe for extreme pest growth: a hot greenhouse packed tight with thousands or millions of a singular crop. However, consumers should keep asking what chemicals have been used on their plants, and ALSO say it’s ok, I will still buy a plant for ornamental use that is not aesthetically perfect.

While I want to keep focus on pesticides, fungicides, and miticides, I also want to introduce the information that commercial growers use liberal amounts of what we call PGRs, or plant growth regulators. These are chemicals that affect a plant’s growth on a cellular level, triggering growth desirable for a retail market. They have been engineered to reduce internodal length (the space between leaves on the stems), artificially “pinch” plants to increase the number of shoots, keep plants denser and shorter, and make them more floriferous and greener. This may sound like science fiction, but they’re engineered off a plant’s own hormonal system that creates these same responses. These PGRs greatly increase a plant’s salability: would you buy the leggy, lanky, non-blooming Nepeta over the tight, dense, compact Nepeta loaded with blooms? These are yet another chemical developed for an aesthetically driven market. Again, the customer than shuns the non-organic basil has no idea that her/his perennial purchase has been chemically engineered for top eye-candy potential.

Has your Nepeta been drenched and sprayed with chemicals? Absolutely. They wouldn’t have made it to your local Lowes without them. Will they harm your family or your specific, local bee population? No, they won’t. Will the wider, commercial use of these same chemicals harm bees and other good insects? Yes. Does your purchase support these practices? Yes. Should you feel guilty? No, definitely not. This is industry standard, and a wider practice than you alone. It’s OK to shop at Lowes, they’re cheaper than your local gardening center; however, when you shop at your independent gardening center you can ask the manager directly what growing practices their suppliers employ. Your concern will make its way up the supply chain, I promise.

For now, enjoy your Nepeta. It’s a tough character, blooming longer than most any perennial, even in terrible soil. It’s a good reminder that even in a complicated system, there is incredible beauty.
posted by missmary6 at 12:43 AM on July 4 [6 favorites]


Hi! I used to own a garden center, and came in to say almost exactly what missmary6 said - although she said in a much more eloquent fashion, and I would favorite her answer 100 more times if I could!

I will add, anecdotally, that our policy was that, although we realized the plant material had been sprayed and 'treated' at the growers, once it landed in our garden center it was treated organically - we did not use any chemical treatments at all. And we had tons of happy lil' honey bees :)
posted by PlantGoddess at 5:43 AM on July 4


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