The Unranter


Gillman We can't believe he even talks to us.

If anybody prides himself on objectivity, it is University of Minnesota horticulture professor Jeff Gillman. Yet, here at GR headquarters, where passion trumps proof every time, we nonetheless persist in the fantasy that Jeff Gillman is a kindred spirit. He is a marvelous writer, and the rare scientist willing to speak to gardeners. And given all the unscientific nonsense in gardening advice, we are sincerely grateful.

I spoke to him Wednesday about his new book, How the Government Got In Your Backyard, the first time this horticulture professor has written in tandem with his college friend Eric Heberlig, a political science professor.

Q: How The Government Got In Your Backyard is something new, in that it deals with environmental issues that range from invasive plants to GMOs to global warming without any of the advocacy that we're used to.  You present all sides, but don't take a stand.

A: I've read Ann Coulter, I've read Al Franken, and I'm tired of both of them.  The facts rarely point unambigiously to a single side's being right.

JGillman Q: Can you give me an example?

A: People angry about pesticides will say that pesticides kill everything.  Well, probably not at the rate at which they are actually applied.  There is a balance that has to be struck.

Q: That's very Obama-esque of you.

A: Thank you. I think he's done a decent job of making compromises.

Q: You don't seem to like the way that climate change has been used as an issue.

A: The idea that CO2 raises the temperature of the atmosphere makes sense, but not necessarily to the extent foisted upon us. By the the same token, we can't ignore our carbon emissions, and the right is wrong to suggest that we can. They are causing ocean acidification, and they are messing with agriculture, in that certain plants become weeds at high CO2 levels. I wanted to take a balanced view, and to offer the politics behind what is happening. That's where my colleague Eric came in.

Q: You seem to feel that the people who write about environmental issues of any kind need to slow down and get their facts straight. Well, experience has taught me that gardening books are full of misinformation. Can you tell me why?

A: It falls into two categories:  First, there are subjects like companion planting, which is probably good, but where there is simply not much evidence to support the claims.  And second, there are subjects for which there IS evidence, but the literature is produced without understanding it.  People take the information second- or third-hand, from the New York Times, which got it from a scientist but may not have understood the science.  It's whisper down the lane. We need to back up our opinions with understanding.


  1. It’s great when someone can see all of the gray in the world, not just black and white. Calm, deliberative writing like his is great for the future of gardening wisely.

  2. A voice of reason! I would love to read a post by him, if he’s willing (I guess I can’t call it a “rant”, although if he does have something to rant about, that would be interesting to read, too). Meanwhile I’ll read his book.

  3. I’ve already read Jeff’s book, and let me tell you, it is full of those fascinating, “who knew” moments when you nudge your spouse awake to read just one more line aloud. For instance, his comparison of the lethality of your morning cup of coffee compared to your neighbors’ lawn chemicals. And he has some very startling and interesting things to say about invasives. In fact, I think I’ll see if we can persuade him to come say them here! More from Jeff Gillman! Always!

  4. Like Sandra, I have developed a crush on Jeff Gillman as well. Mine came on while reading How Trees Die & has continued each time I read one of his blog posts or more formal writings. Even when he’s debunking one of my favorite plant myths, he does so in such a calm, reasoned way that I can’t help but admit that he’s right & that I need to ask more questions of those proffering garden advice.

    @anne : he blogs, along with Linda Chalker-Scott, Bert Cregg & Holly Scoggins over @ The Garden Professors.

  5. (Not sure if my first attempt at commenting was deleted, so apologies if there is a duplication.)

    I think I would have called him on the Ann Coulter/Al Franken comparison. However, I agree it would be great to have some debate among garden writers about what you think is common misinformation in garden writing. Unleash the rants, I say.

  6. Thank you for acknowledging that passion trumps proof at GR.
    Sometimes, I worry about the tenacity of all four of you, in the face of reasonable rebuttal, but then I remind myself how accomplished all of you are in your respective careers and that your passionate opinions have been instrumental in keeping your profiles high – the dream of every garden writer.
    This interview has been a most illuminating post. It is most appreciated.

  7. I had the privilege of meeting him last year at the annual Green Bay Botanical garden spring seminar. He was quite impressed that I had a first printing of his first book and kindly autographed it for me.

    I think his topics are spot on and I believe there are many gardeners that should read what he writes.

  8. I also have read his books and value research vs feeling of what sounds good. His trials and comparisons are very helpful to my work as a Master Gardener volunteer. I look forwar to reading this as well. Nancy

  9. Jeff’s reference to companion planting gives an interesting insight into the way that the mind’s of people like him work. He says companion planting is ‘probably good’ (whatever that means) but then says there is not much evidence to back it up.

    If I plant single calendulas around my garden and in my greenhouse then the place is alive with hoverflies which spend every daylight hour laying eggs among aphid colonies. Their larvae then eat the aphids and the need to reach for pesticides is removed.

    Now do I really need ‘evidence’ to tell me that what I see happen with my own eyes is really happening – and works? And why has there been so little research on companion/complementary planting, I wonder? Perhaps one of the reasons is that it doesn’t make a whole heap of money for anybody, and never will.

    Just letting self-sown calendulas etc flower among your other plants will reduce the incidence of pest attack: it’s called gardening in balance with the rest of the natural world. Jeff hands the anti-organic gardening brigade bullets on a plate when he trots out the well-worn message that companion planting is somehow not valid because no research has been done to make it proper and respectable.

  10. @John Walker – the problem is that despite seeing evidence of hoverflies which lay eggs among aphid colonies and evidence that the larvae eat the aphids, there is no direct causation between planting of calendulas and a reduction in aphid population.

    For example, hoverflies may be attracted to a garden without calendula. Or, the aphid population are actually being consumed by lacewigs that were attracted by other plants in your garden. Or, there is a mysterious fungi that appears right during midsummer that kills off the aphids.

    The point is that without direct evidence that planting plant A will improve plant B in some fashion, it is simply just a correlation. One can continue to keep planting calendula and see satisfactory results and attribute it to the presence of it in the garden, but I personally am more inclined to find the truth of the matter as to what direct effect the calendula has on improving my tomato growth. It’s not a matter of formalities – it is a matter of evidence based gardening. I like to know exactly what is myth and folklore, and what is actually true myself for my gardening knowledge. I don’t think that it’s anti-organic whatsoever, it’s simply logical.

  11. I, too, like to have evidence and the results of rigorous experiments. However, my state will not pay for this. The free market will pay for it. Hallejulah. Therefore, unless the calendula growers form a cartel, there will be no study, and therefore, no emperical evidence.
    Cindi, denizen of the land of McD and Cuch.

  12. He is a bit dreamy. Although I’m swayed by the science talk over at Garden Professors. Would it be too wrong if one of the GR ladies would post about the men of horticulture? So we could have a little discussion. With pictures of course! Sorry male GR readers 🙂

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