A while ago, Carol over at May Dreams Gardens asked a question in one of her posts. Specifically, she asked if there were other gardeners out there who had conceived of specific plant dislikes, plants they would NEVER plant in their gardens.
At that time, I responded rather decidedly that violets were something I would never plant on purpose. In fact, I have some regrets about planting violets, as they are very invasive and when they invade an area they successfully kill most everything around them.
I have been engaged in a great eradication program the last couple of days, and it came to me as I was doing it that this is another plant that I would never plant in my garden again. Specifically, it is the Showy Evening Primrose, (Oenothera speciosa) , which opens any time, not just in the evening. See the wash of pink around the irises in this bed? Isn’t it lovely?
This is a direct quote from the comments section of the Audubon Society “Field Guide to North American Wildflowers (eastern ed.)”:
A hardy and drought resisitant species that can form colonies of considerable size. The flowers may be as small as 1″ wide under drought conditions. The plant is frequently grown in gardens and escapes from cultivation. The flowers of some members of the genus open in the evening so rapidly that the movement can almost be observed.
Read that statement. I did, when someone gave me a start of this plant. I focused on the part about “hardy and drought resistant”, and didn’t think about the implications of “colonies of considerable size” and “escaping from cultivation”.
Now, think about this. If it makes colonies of considerable size, certainly that means that it has some way of spreading successfully, right? And if it frequently escapes from cultivation, surely that should be taken as a warning, correct? Needless to say, a plant that is “hardy and drought tolerant” may be quite successful in a site where it has escaped from cultivation.
Boy oh howdy, is this ever true. I have had people ask me for a start of this plant when they have seen it in full bloom in my front garden. I look at them and tell them that if they plant it, and it is transplanted successfully, they had better REALLY want it, because once it gets started they will REALLY have it.
I would counsel any person who contemplates this absolutely gorgeous flower in a pot in any garden center to think about what it will be like when the garden bed they plant it in has nothing else in it. Look at this picture of my front garden. I love the way the primrose has painted a big pink swath at the foot of the redbud tree. It is actually quite beautiful.
There is only one problem. When I began pulling it out today, the swath of primrose had grown to over twice the size it is in that picture. It did this expansion in ONE season. ONE! It was killing the wormwood at the corner of the walk (if you can believe that! Killing wormwood, a highly successful thug plant!), has smothered the sedum that was under there, was quietly strangling all the day lilies that are in the right side of this shot. Back in the middle, the section of primroses there had almost completely killed my miniature rose, the lavender, was working on beginning strangulation of the peony.
I have gotten into this eradication program just in time.
Look into this ethereally beautiful face. If you have a sunny bank that needs populating, somewhere where you don’t intend to put anything else, someplace that needs protection from erosion; by all means populate it with Showy evening primrose. You will not be unhappy. They bloom profusely in the spring, have very nice green foliage all summer, rebloom when it cools off in the fall, and the foliage is a striking scarlet when it finally gets hit by frost.
But it has serious rhizomes that creep under and through all the roots of other plants, strangling them from beneath. The root system becomes so thick, nothing else can get any water or nutrients. From above, the plants get tall, and covered with thick leaves. They lean over their neighbors, and smother them from above while the insidious rhizomes strangle them from beneath.
Would I ever plant this again? Not in a flower bed where I wanted anything else tender and beautiful that needs nurturing to grow. Out in the wildflower strip where the other natives have the proper defences and ammunition to fight it off? Yes indeed. I would put it in a prairie restoration as well, in its own native habitat.
Gardeners beware! Be careful what you ask for, you might just get it! Oenothera speciosa is the thug plant to beat all thug plants.
Plant it at your own risk.