Some plants should come with a warning label – caution, will seed freely. This is also true of garden compost and bagged soil amendments – be forewarned – hidden seeds included. If you have bought or better yet been given that special plant that in no time has established itself everywhere in your yard, or you purchased the bag of steer manure or garden compost or had a unit delivered only to find it full of unwanted weed seeds, you have a direct experience of what I speak. Bulbs can be like this as well – warning- propagates aggressively. I laughed when my good friend bought three gallon pots of grape hyacinth. I told her to only plant them where she would like a few thousand to spread. I know because I have filled many two and three cubic yard bags with the ones in my garden. This was only after carefully spreading them around the first two years.
I started my perennial gardening with hardy geraniums. In the first years I bought any geranium that had a different name. Some were tidy little plants that stayed in place or spread modestly. Others grew large in a season and I happily divided them up and planted them around, mainly G. oxonianum ‘A.T. Johnson’ and G. psilostemon. When you have a lot of dirt and a small budget this kind of plant is quite welcomed as it fills the space. You may not be thinking and throw the unwanted ones in your compost and then at a later date spread the compost around. Oh my, those plants are showing up everywhere. And so my hardy geraniums have. I still have a fondness for most of them but the ones whose leaves have a distinctive odor, the macrrorrhizum family, I put in the lawn trash almost without exception. There is always an exception.
Plants are smart (read Botany of Desire by Michael Pollan) they will woo you into letting them spread. I have a Malva zebrina which I took from my friend Susan. It grows to about three feet and is filled with beautiful lavender swirl flowers from early summer till frost. The variations from one plant to another are intriguing. What could be a problem with this you ask? When you find about 100 of them the following year you may have a change of heart. I bought a red veined sorrel in a 4″ pot that came with a hefty price tag for a plant of that ilk and size. It seemed quite precious. I now have hundreds if not thousands. Anyone having a plant sale is always welcome to dig those up. Rosa Rubrifolia anyone? A lovely tree rose with blue green foliage and a sweet single petal pink rose. You can find small starts of this all around the mother rose and within 15 feet in most directions.
I still shudder when I remember the plants that became gardening disasters. The worst was a variegated Australian grass given to me by the plant buyer at Portland nursery with the instruction to propagate it. I planted it by my greenhouse under the water cooling system. Lovely, I thought! When the first sharp pointed spike poked up through the greenhouse floor a savvy gardener would have acted immediately. Being generally overwhelmed I thought I would take care of it later. So for two years I diligently snapped the shoots off always intending to finally deal with the problem. On the third year the shoots were showing up three quarters of the way down the greenhouse floor. It was a major excavation project that took a few days and required two passes till it was all out. This is a plant for the freeway median line: invasive, indestructible and needs no care.
I wish I could say I learned my lesson. About four years ago I had a handful of garlic and onion seed that I blithely tossed into a long bed at the back of the property. I have had garlic growing in that bed ever since. In general this had been just a pesky problem until this year. Last year I made a great effort to get all the garlic out and prevent it from seeding anew. So I was really surprised when new plants filled my beds again. I’m not sure just what I have as it looks like a young tough scallion but smells faintly of garlic. What I do know is that it is everywhere. I filled a trash can with the ones I dug from the small bed it had invaded. I still have the large one to tackle.
Sometimes when I’m at the farmers market or a plant sale I want to warn the person buying a certain plant. On a few occasions I have done so. I whisper that the plant will freely multiply and they don’t need three as one will be sufficient. I am still amazed that the red vein sorrel sells for $4.00 a piece. I have a fortune on my hands if I was only willing to dig it up and sell it.
Or how about that sweet smelling mint plant? Put it in a barrel or you will spend your gardening life time pulling it out. Another red flag plant – violets. My friend lost her whole garden to violets. They grow by under ground runners and seeds. I’m so afraid of violets that I once threw out a newly bought plant because I found a violet growing in it. I did plant one 15 years ago. I pulled it out before the season was finished, and yet, I still find an odd plant growing every year. Take heed, you’ve been forewarned!
Don’t get me wrong, I have some plants that spread that I totally love. Columbine can always find a spot in my yard, or a wispy yellow grass a friend gave me. I have a small purple hardy geranium that flowers in early spring that seeds around and the G. phaeum ‘Merry Widow’ lines a bed in part shade. Sedum courses through my path stepping stones along with Blue Star Creeper, and I have a love / hate relationship with Astrantia which grows in almost every flowering bed I have.
If you come to my house and I offer you a plant I will always mention, “Remember I’m giving you this plant because I have a lot of them. You will too.” So when a friend offers you an extra from their garden you might want to investigate before accepting. This might be a plant that should have a warning label!