Most of the fast-spreading plants in my garden arrived as local weeds. Here they are (plus a couple that I planted deliberately) and how I’m dealing with them. 

Creeping Jenny as potentially harmful, or a great garden plant

Creeping Jenny in my back yard, in spots where a taller plant wouldn’t work – beneath a hydrangea, on top of a wood-chip path, and between flagstones.

My recent post extolling the eye-popping qualities of chartreuse foliage, I showed off the Creeping Jenny growing between my flagstones and promised to research whether they’re invasive in my area and if so, what I should do about them in my garden.  Here’s what I learned.

It’s not on Maryland’s invasive plant list, even as an additional plant considered.

Next, how else to determine if it could cause harm on this site?

But digging deeper, is there any way this common local weed could harm a nearby natural area? Since it spreads only by runner and would have to cross the street to get to a natural area (which itself is covered with invasives at the ground level), I say no. 

But is it too thuggish for my garden? Not at first but lately it’s gained steam and I noticed it overpowering the groundcover Sedums that I want to keep alive, so I’m removing them from around the Sedums.  That’s the only plant that’s in harm’s way (so far).

I do love Creeping Jenny’s color and its extremely short stature, enabling it to be grown right under shrubs without blocking air or light. And between flagstones, no other plant is short enough, and mulches just wash down the slop during heavy rains.  

And unlike my Sedum, I can step on Creeping Jenny, which I do almost daily, without it breaking off. 

Ajuga – another one that’s slow to attack

For 10 years there was just one little patch of Ajuga (planted by a previous owner) amidst a mass of Packera aurea. But this year I noticed the patch was much bigger, having killed some nearby Packera, so it has to go! (Easier said than done; it’ll take years to remove all the sneaky bits.) I did move some to a safer spot around shrubs.

Groundcover comfrey – super-spreading pollinator magnet

This ground cover comfrey, a passalong plant from a nearby woodland garden, immediately took off in mine, and I’ve loved watching bees feed on it for its long bloom period. I also loved how fast it filled in – until it became clear it would quickly cover the whole border, and maybe the whole garden.  Above you see one of the borders it was taking over.  I removed all but the patch on the right far.

Still this super-spreader is a plant I’ll keep – within bounds. Not only do bees love it; it’s beautiful and completely block out any new weeds. It’s truly one of the most effective groundcovers I’ve ever seen, and it’s happy in shade.

Black-eyed Susans – the gift that keeps on giving

Rudbeckia hirta is my state flower, it blooms for a long time, is super-cheerful, and will fill a bed or border in no time.  In fact, I’ve often recommended that new, empty gardens be filled in with passalong black-eyed Susans – to be edited out as other plants are added and mature.

That’s what happened here in my front yard after I removed the horrible arborvitae hedge and had lots of new space to fill. I used all the Susans I could find, but removed all but one group as I gradually increased diversity in the border. (I noticed very few insects visiting them, anyway.)

Mexican evening primrose and Rose Campion can spread all they want

I love these air-borne weeds and to them I say “More, please!” But they come and go on their own accord.

Bronze fennel – another hit with butterflies and hummingbirds

Growing alongside a Major Wheeler coral honeysuckle, the hummers can’t resist stopping! So I’m okay with fennel’s promiscuous self-seeding in my border;

Joe Pye Weed and Wood Aster seem adapted to each other’s spread

I grow ‘Little Joe’ Joe Pye Weed and wood aster together in this small border and while they both spread, it’s seemingly not to the detriment of the other. It must help that they grow sequentially – the wood aster emerging early and the Joe Pye weeks later.

But you’re going to hate this next one – periwinkle 

Finally, I’ll mention one plant that IS on Maryland’s invasive plant list – periwinkle, or vinca minor.  As of 2017, sellers must display a “Tier 2 sign” about its invasiveness.  

Admittedly, I DID once defend periwinkle in places where it can’t escape – like in this spot between my garden and parking lot, surrounded by concrete and asphalt. It can’t climb trees, so the tree and the shrubs I planted there are safe.  (Curiously, in the Maryland neighborhoods where I’ve gardened, the usual complaint about periwinkle is that it doesn’t spread enough.)

But in garden beds it’s a very different story! I complained in this post about its stealth nature, having not spread much my first 8 years here until suddenly it’s overtaken some plants I want to keep. Now years after deciding it had to go, I’m still finding little bits of the stuff.