Some plants have unfortunate if not unjust names like Helleborus foetidus (which to me doesn’t stink at all) while others with the name weed in them might frighten off people. I found this experience when suggesting Centaurea montana also by its common name Knapweed to people. Yes, it is weedy and sometimes difficult to eradicate from unwanted positions, but for gardeners with some space or gaps to fill, this spreading habit can be an advantage (for a time).
Yet, there is another, and more important, aspect from the pro-side to me: Centaurea is one of the earliest to rise and one of the latest perennials to go within a growing season and, if cut back after flowering, it could flower 3 to 4 times a year. Thus you can use it as a stable colour within an otherwise changing environment. I find this opportunity extremely exciting and reassuring since it works as well with decent spring colours as with bolder summer arrangements: Like the reliable bread in your diet: you can have it with cheese, bacon, sausage, jam, honey, as crumble inside a dumpling, but also on its own. And there is always room for a new experiment with colour schemes without the need to use new plants. On the contrary, you will be likely to get more. (I submit this contribution with caution as gardeners in Australia or elsewhere might tell quite a different story, as was the case with dittander.)
I often wonder (or have missed it) why it is not more often stated, that many plants (apart from roses where the dead heading became a mantra) flower at least a 2nd time when cut back: Not only the usual suspects like Alchemilla or Geranium, but also taller perennials like Delphinium and Echinops. This quality puts them into a totally different league to, for instance, monkshood, although they often enjoy the same playground with me.
At the moment of writing the proud and dangerous monkshood deigns to flower with the 2nd flush of delphinium in some areas although it had shown its first leaves at the same time if not slightly earlier in spring. This, of course, is the moment when monkshood best reveals its relationship with the winter aconite. And it has seen all the centaurea bouts come and go, whereas the latter will see the monkshood go.
Here is a sequence of this year’s combinations with Centaurea montana. I would have loved to insert more English autumn pictures with centaurea but I have to rush to Germany very soon to make cider and look after our gardens and its weeds there, including our centaureas.
[Click through the slideshow to see the different seasonal Centaurea plant combinations]