I first experienced problematical gift plants when I worked with a client who had been given a large volume of daylilies by a friend. They were rejects from her garden – the orange ones often referred to as ditchlilies. By the time I arrived in her garden, she had over two hundred of this dreaded plant, which meant that she had at least 2,000 individual bulbs. She had tried Roundup, but of course it only burned the foliage on the top. In one of the most backbreaking projects of my life, I dug them all out. It took a month, and thereafter we had to watch for the stray bulb or two that escaped. I have these delightful things in three surrounding yards. I actually reach under the fences to rip them out. There is a quarter acre garden about a mile from my home that has nothing else. And my neighbor’s ditchlilies have gone under his fence to establish a two foot border in another another neighbor’s yard.
Goutweed, also known as bishops weed, ground elder, and by the dignified moniker of aegopodium podagraria, is another very invasive plant. I see this in almost every yard in gardens with part to full shade. If you go to the dictionary and look up pernicious, you will surely see the smiling face of goutweed as an illustration. Since it loves to curl up with ivy and vinca, eliminating it with chemical applications would damage or destroy the other plants, which are far more desirable to many gardeners. So the gardener ends up pulling out the individual plants - for the rest of his or her gardening existence. It is unkillable, and it invades everything, including the lawn. It’s for sale in garden centers. And to add insult to injury, its favorite location, in my experience, is among the desirable groundcovers I noted above. So spraying is out of the question.
Campanula rapunculoides is probably a gift from your neighbor. But not in a pot – it tends to creep under the fence from the next home. It arises with beautiful blue bells and you are charmed. I know I was. Then two years later it’s everywhere, spreading by taproots that send out little threads that spread it some more. It will invade your garden, the neighbor’s garden, cross the fields to go into the woods, then turn up at your childhood home. It grows in full sun, part shade, and the taproots can be over a foot long. And unless you remove every tiny thread, it will come back. Roundup simply burns the top. Smothering it with newspaper over the winter simply delays its appearance for a couple of weeks in the spring. The cure? Dig up all your soil (I use a dandelion digger and a shovel), and then put a trench between your yard and the garden that is sending it your way. That’s my summer project.
Ostrich ferns are probably familiar to you if your neighbors have them, because they will travel from their yard to yours. My sister in law was given a few and complained that they took over her entire garden. She then, of course, offered some to me. Why people offer invasive plants that have taken over their yards to other people I really can’t comprehend. A fellow master gardener chuckled to me about deliberately giving invasive plants to a newbie and seemed to think that she had done something quite clever. This is a fern that grows over a foot tall and then browns out, so it’s quite ugly. It moves into lawns, perennial beds and what have you. And garden centers sell them!
Lysimachia clethroides, also known as gooseneck loosestrife is a plant I occasionally see in gardens. And when I do, there is a ton of it, and it is unaccompanied by any other plant. My personal experience explains why. When I was first getting established in my new home, four gooseneck loosestrife were planted in my beds. Four months later, they had completely taken over the bed and killed everything else. When I pulled them out, I was stunned by four foot roots. It spreads aggressively by underground stems and completely fills beds. It does not play nicely. Amazingly enough, it is in many garden centers, is in prestigious catalogs and some of the more expensive gardening publications. The picture above is from a neighbor. This planting is at least twice the width shown above. It was one quarter the size a year ago!
My recommendation: when someone insists that you MUST have a plant from their yard, be gracious, of course, but cautious. I have often declined, only to find that the person turns up at my home with a box of the plant. It’s a tip off – so eager! Smile,take the box, put it aside and do some research before willingly inviting a thug into your garden. If it is indeed a thug, ditch it - but not in your compost bin!