Invade me, baby

That plant is aggressive. It gets really big. It elbows out neighboring plants. It spreads all over and covers a lot of ground in a hurry.

This quote from Craig's comment on Amy's plant lust post resonated with me—I had just briefly posted about invasives on GWI. Though I spend hours every summer pulling my neighbor's silver lace vine out of my trellis, cutting back wisteria, keeping English ivy at bay, and yanking viola out of the ground, I still find much that is admirable about these aggressive cultivars. Perhaps my worst fear as a gardener is that nothing will grow, that I'll be stuck with yards of bare earth with little plants stuck here and there. Some people like nothing better than a neat yard, with every plant kept in its rightful place. I like things to be full—lush, green, overflowing.

And for that, you can't beat a few well-placed aggressors. I'm a busy person, so I like my plants to be busy too. The silver lace vine (Polygonum auberti)—though it actually belongs to my neighbor—never fails to awe. No matter how brutally I cut it back, usually right into the joints of old wood on the fence, back it comes, within a week regaining all the lost ground. Every summer, unless hindered, it handily covers an entire utility pole. Which is an improvement.

Under maples trees, English ivy works well, and looks appropriate. You just have to pull it back regularly. I use it as a framework for a bed of bulbs, various perennials, and ground cover under a big tree. I should fear this plant, but I'm grateful for its utility in a difficult situation. Another good choice for such situations, sweet woodruff, is more cheerful in foliage and flower and seems to grow anywhere.

Experimentation is necessary to see if it's possible to introduce competition into beds where plants such as these dominate, but I'd rather be filling in holes in a nearly full area than the other way around. My admiration for the ability of plants to propagate and spread with no help from me has stopped me from making many necessary changes in the garden. (I should be mixing and arranging the hosta and ferns instead of pitting them against each other from opposite ends of the same bed to see which will engulf the other.)

There are certain weeds/invasives even I will not tolerate. Clover (the yellow-flowered type), bishops weed (too boring), mint, and many of the underground spreaders are too unattractive/ill-behaved even for me. But if someone out there has created a great garden using those plants, good for them. I'd like to see it.

If you consider that the first duty of a plant is to grow, and you have a rather difficult urban space, you learn to treasure your invasives.

Comments

[Jodi DeLong]

I don't have a silver lace vine, but I do have bittersweet male and female. They're impressive, too, and while I understand some parts of North America have issues with them being bad, they haven't self seeded nor attempted to take over here. I love them in the fall, and I have them in places where I want quick and easy privacy screening. Going to try your silver lace vine in another such spot.

And I'm excited that the sweet woodruff has established itself in a couple of problem spots where other plants have failed to deal with the situations. Now if I could just get the blue woodruff to establish and selfseed reliably...

In my opinion, goutweed/bishops weed/ground elder/Aegopodium shouldn't be sold in nurseries. But as you say, even naughty plants have their fans. Chacun a son gout! ;-)

[Martha]

I do treasure a few heavy spreaders... but I have fought running bamboo and am now fighting nutgrass, and dear GOD how I hate them!

[Ellis Hollow (aka Craig quoted above)]

Let me quickly go on record as being against invasive plants. There is a huge difference between plants that are aggressive in a garden setting and those that are invasive -- that escape into 'natural' areas, displace native plants and disrupt ecosystems. Some of my favorite plants are fairly aggressive natives that I import into my garden beds.

[Claire Splan]

I agree, Elizabeth. I've had aggressive spreaders that have driven me crazy, and others that I happily nudge along, hoping they'll do their aggressive thing as much as their little green hearts desire.

And as for the distinction between "aggressive" and "invasive," it still seems to me a very artificial and arbitrary distinction. I recognize that it can result in unwanted destruction and we may choose to intervene in those cases, but when you get right down to it, it's just a case of "survival of the fittest."

[Peter Hoh]

A couple of years ago, I put some bishop's weed in a difficult spot between sidewalk and curb. The soil there was badly compacted. I barely mulched it, and watered it only when necessary. The weed thrived, of course. This year, I dug it all out and discovered that the soil beneath it had turned into a lovely loam.

That's an experiment I will try again.

[MaryContrary]

Agreed that there is a huge difference between plants that are aggressive in the garden (aka "garden thugs") and plants that may or may not be aggressive in the garden, but are exotic invasive species that do a great deal of ecological harm in natural areas.

[firefly]

I have Campanula rapunculoides and Oxalis stricta rampaging through the garden. They were here when I got here, and I pull them up only when they crowd other things (the campanula has a bad habit of growing up through and shading out other perennials, even the violets, which makes it difficult to pull).

I also planted two 4-inch pots of Monarda didyma which have already run away from their original spot to places they prefer. (Cheeky, aren't they!)

Most everything I have read says it's better to have the ground covered than bare, and since it will take years for me to load the place up all the way to the groundcovers, I consider these plants allies.

They just need a good strong leash.

[susan harris]

Great post, E, and the example of ivy is a good one. I used the existing ivy along the sidewalk to cover the chainlink fence there, and I just clip it back occasionally. But people ask me accusingly: why haven't you ripped it out? (I ask what harm it's doing in this location and that's the end of it.)
And a client had ripped out all the ivy on her bank, then called me about the erosion situation she'd created. Big picture, people!

[Amy Stewart]

I have been the happy captive of a very aggressive lamium for a few years now. It never complained about the uneven light, poor soil, total lack of water in summer and flood conditions in winter, and it ate weeds for breakfast. It enjoyed any form of abuse--clipping, running the rake through it, ripping it apart. Whatever, it said. Give me more.

I've now decided to actually do something with that neglected spot in the garden, so I hired a teenager to hack it out. I'm saving a few plants for my mother, who wants something that will grow under her magnolia. I agree--an aggressive plant can be a very, very good thing.

[layanee]

It is difficult to know what is invasive prior to it making a 'list' and lists are very geographic. I have never had a problem with ivy, lamium and most of the other plants mentioned. I have Winged Euonymus which is on the invasive list in my area but I have never seen any seedlings from it. I do have some lovely poison ivy though and I do believe that is native!

[David]

I like your theory about the fear of bare ground. I'm the same way. That's why I've got yarrow growing all over the place. It's so aggressive that the weeds turn and run the other way when they see it coming. Plus, it has nice feathery foliage and beautiful flowers.

[Mick Lind]

For biodiversity's sake, don't encourage invasive nonnative plants. I live in the Pacific Northwest where ivy is one of the worst weeds. It's truly smothering the forests. I cringe when I see it in gardens, especially when it's in fruit (bird's carry the seeds into the wild) or running under the fence.

[Earth Girl]

Permit me to rant back:
You can have some fun with aggressive plants, garden thugs, when you have room in your garden to pit them against each other, even those that spread through stolons. The term "invasive" has a specific meaning for those plants that "are non-indigenous species or strains that become established in natural plant communities and wild areas, replacing native vegetation." By using the term invasive for non-invasive plants, we undermine the truly horrific results of invasive plants on biodiversity and ecosystems.

[Eliz]

Earth Girl, you are perfectly correct to make the distinction. I knew people would understand how I was using the term, but it's not the strict meaning.

[Peter Hoh]

I make a distinction between aggressive and invasive. Aggressive describes the behavior of a plant in my garden. Invasive describes the behavior of a plant in the wider environment.

The Renegade Gardener wrote an article titled "Space Invaders" about aggressive garden plants. Sorry that I can't link to it. It's archived under "Plants" section of his site.

[Michele Owens]

I think the truth about thugs is that they are only controllable by bullies--in other words, by active gardeners willing to dig them up when and where they turn into problems.

People have told me that I'm insane to allow violas in my flower beds. And indeed, I'm constantly yanking out unwanted plants. But man, when they bloom with the tulips, they are so lovely and delicate, the world's prettiest edging plant! I love the colors--I'm mostly keeping the white and allowing only the occasional blue. And, as you mentioned Elizabeth, they are a huge help in filling in the blank spots in a relatively new garden.

One of my neighbors with an extremely classy little Greek Revival house has a very simple, but striking yard. There's nothing there but hemlock hedges, a specimen bush or two and Bishop weed underlying everything. It's pretty great.