Book Review: Are “Aggressive” Plants a Blessing or a Curse?

The purpose of plants is to make more plants. That is all they want to do. Gardeners sometimes frustrate, sometimes tolerate this will to reproduce.

Photo from
Photo from

Some plants are particularly successful in this endeavor. Oftentimes gardeners consider such plants mildly criminal. How often have we heard the word “thug” used in the context of the garden, as if Monardas were members of the Blackstone Rangers? (Confession: I have used this adjective on plants a few times myself.)

Plantiful, by Kristin Green, suggests a different point of view. She lays out how gardeners can collaborate with the botanical drive to reproduce. This collaboration enables gardeners to create large, bountiful gardens at a greatly reduced cost.

kristin green
Kristin Green. Photo from

Green practices what she preaches. She works as a professional gardener at Blithewold Mansion, a non-profit, public garden in Rhode Island.

The book is divided in three parts – the first deals with plants that spread primarily by seed. The second covers plants that spread mainly through roots, rhizomes, stolons, and stems.

Each section begins with a very clear and practical discussion of relevant propagation techniques for that group of plants. Then there are thumbnail descriptions of 50 plants of each type (150 plants in all – annuals, perennials, and smaller shrubs).

I was particularly interested in the third section, which deals with overwintering tender perennials. The author enticed me with her discussion of how tender perennials can be used to keep the excitement at a high pitch in beds and borders.

In the past I have tried to overwinter Caladiums and was rewarded with bags of smelly tuber mush. Now I feel the confidence to try again. Also, I learned that I can overwinter just about all of my favorite container plants, including Pentas and Lantana. When you consider the cost of buying these plants every year, it is certainly worth the effort.

Anise Hyssop
Anise Hyssop spreads by seed.

There are a couple of caveats to “working with a generous nature”, as Kristin Green puts it. For one thing, generosity exists on a continuum. There are some plants that are so excessively generous that you may not want to deal with them in your garden. Which plants falls into that category will depend on where you garden.

Great Merrybells is a fine spring wildflower native to North America - and no pushover.
Great Merrybells is a fine spring wildflower native to North America – and no pushover.

Also, vigorous plants can’t simply be stuck in the ground and forgotten. The gardener has to monitor, set limits, and propagate. Though I enjoy watching two strong willed plants struggle for dominance. Sometimes the results of these struggles are surprising.

For example, Bishop’s Weed (Aegopodium podagrarium) has a fearsome reputation. I have some variegated Bishop’s Weed that I keep in difficult spots along with the very demure-looking Great Merrybells (Uvularia grandiflora). To my surprise, the Merrybells are bullying the Bishop’s Weed.

Wild Bergamot and Bee Balm 'Raspberry Wine' spread mightily by root, like other members of the mint family.
Wild Bergamot and Bee Balm ‘Raspberry Wine’ spread mightily by root, like other members of the mint family.

Plantiful is definitely an excellent book for a beginning gardener, especially one who is both ambitious and on a budget. But it is also a useful and entertaining book for persons experienced in the garden.

Do you celebrate aggressive spreaders, or shun them?

55 Comments on “Book Review: Are “Aggressive” Plants a Blessing or a Curse?”

  1. I let them do their thing and then when they’ve done too much I dig out half of them and give them away. Many people have started gardens that way, including me.
    Overwintering isn’t hard but it does take room and that “cool, dry, dark place” that many don’t have. A root cellar would be great but we don’t seem to do those anymore.

  2. Aggressive plants can be a blessing! I used a native obedient plant (phytostegia) to crowd out a patch of weeds and ratty wood anemone. The anemone blooms in the spring and then the obedient plant takes over from there. Even the dandelions didn’t stand a chance. I fought fire with fire and it worked. But they do need to be sited carefully. I have the same book and thought it was a keeper.

    • Really, no aggressive plants? No Monardas, Agastache, or New England Asters? Though maybe your definition of aggressive is more restrictive than mine. In my mind, doing without all aggressive plants would be very limiting. As for celebrating the capacity of reproduction, what I would celebrate is our ability to harness that capacity for our own pleasure, as you say.

  3. I left a comment but don’t see it. I have this same book and think it’s a keeper. I used native obedient plant to crowd out a ratty patch of weeds and wood anemones. The anemones bloom in the spring and then the obedient plants takes over. It was like fighting fire with fire.

  4. Ugh – you just reminded me of the mint that is taking over my entire yard. I grow some “thugs” in containers, especially herbs, others are relegated to areas where nothing else seems to thrive or beds where I want them to take over. I overwinter some container plants in my attached garage – it stays above freezing but just barely.

  5. Sounds like a book right up my alley! Creating a garden is fun, but then seeing what happens as the plants grow and spread is what makes the garden magic. If they just sat in their places looking mildly uncomfortable I wouldn’t bother, and just go with the plastic version. I’m not saying I want a weed patch, but with a little editing I keep the spreaders in check.

  6. Totally depends on what it is. If I know it’s especially vigorous, I might site it in a challenging spot just so I don’t have to work so hard to control it. It is a good book – I got it in my Timber Press swag bag at the Fling. 🙂

  7. I have to differentiate between attractive thugs, er I mean successful plants, and the non-attractive. For example, drifts of Lysimachia in the driest spot in my garden are a godsend, since nothing else will grow there and the golden Lysimachia barely spread there. On the other hand I have much more ground elder than I can enjoy and it gets ugly when it sets seed!

  8. It sounds like a very interesting book Jason. I like invasive plants. You have to think a bit more carefully about how to use them. If they cause you a lot of headache it is because you have not put them in the right spot.

  9. I enjoy those that spread until I get to the point where I just can’t provide a home for any new divisions. Then I dig up for our MG plant sale, and I may move a few out to the wetlands border. I can’t throw a plant away but I can give them a chance to survive and leave it up to them. I love Bishops Weed in containers. 🙂

  10. The scariest plant I grew in Glen Ellyn was Ranunculus ‘Buttered Popcorn’ which was a real beauty but spread with frightening speed. The tiniest remaining root would begin to sprout yet more growth much like Quackgrass. The worst part was the rash I would get from handing it without gloves. Best left for containers — gloves only!

    Thanks for a great review. I have added this to my LONG list of books to read!

  11. I must confess that I like thuggish plants, and I have several that should be banned, like Rununculus ficaria, Houttuynia cordata, Corydalis heterocarpa, and wild violet (wish I could get rid of that last one).

  12. Looks like a great book, that maybe I should buy. We have that desirable space down in our cellar but so far I’m not doing very well overwintering there. There’s a lot I need to learn. But am amazed by the competition between the Uvularia and what we would (?) call variegated ground elder. In Britain we would assume no competition!

  13. It depends on the climate, soil conditions, placement, and planting zone many times as to how aggressive a plant becomes. Honestly, I have had more trouble with true native plants than those same plants bred to be better controlled. Monarda is an example for instance. Goldenrod on the other hand, it does not matter, native or “improved” it only belongs where it is allowed to take over. I have not found a variety – the plant tags lie – that will stay behaved. I never heard the term professional gardener. I’d ask what qualifications make one so, but I am guessing there is none.

  14. I wish this book had been available when I first started seriously gardening. There are so many ‘thug’ plants available in nurseries, I came home with more than a few before I got myself educated on them. Of course, as you point out, what might be a thug in one person’s garden is the saving grace in another.

  15. Great review! I’ve started to overwinter a few plants in my sunroom, and I’m thinking about adding more. In the past, I didn’t try it because of my cats. But now we’re closing off the sunroom during the winter, so it’s an excellent place to save annuals (like Lantanas, Pentas, and others) for the next growing season. I tried saving the Impatiens, though, and it didn’t work. Interesting about the Merrybells and the Bishop’s Weed. That is surprising!

  16. Seems to be another inspirational Timber Press book (I love them, they’re so quirky!) and maybe a bit similar to ‘Blackbox Gardening’. ‘Thugs’ can be very helpful but as always it helps to know your plants to avoid desaster. Thanks for the review – I like your sense of humour 🙂

  17. Interesting book review. Sometimes I get tired of plants running all around and sometimes I’m so grateful for their adaptability and persistence. I’m much more careful about what I plant these days, but someone gave me variegated Bishop’s Weed for my previous garden. I’m a little embarrassed to have it sometimes, but it makes a nice ground cover.

  18. This sounds like a really interesting book; thanks for reviewing it. I think we only call our vigorous plants “thugs” when they out-compete some other plant that we really wanted to grow by their side. I like dividing plants that grow and reproduce vigorously in my garden and using them elsewhere in the garden, too. And, like you, I have learned to grow the aggressors near one another and let them fight it out. In The Living Landscape, Darke and Tallamy actually recommend the practice of combining plants that are equally aggressive (or timid).

  19. This sounds like a useful book. The question of thuggery depends on where you garden of course. Some plants struggle to survive in one garden and threaten to take over every inch of space in another. That is why we have to be so careful with non- native introductions in the wild.

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