There is a thin line between an endearingly vigorous plant and a herbicidal maniac. Last year I made a new border in the bottom garden; it wasn’t “designed” as such, it was one of those spur of the moment “let’s just do it” events that quite often happen in my world. So the bed was dug out, prepared well and planted with bits and bobs we had knocking about the place. Although extremely exposed, it is a sunny (relatively speaking) part of the garden and well-drained. In went a small amelanchier grown from seed, penstemon, achillea, helianthemum, marigolds, doronicum, all of which had a pleasant summer, settling in nicely enjoying both the fine weather and the ample rain. Some it would seem made themselves a little more at home than others. It came to light today that Achillea “Cerise Queen” had been quietly intent on world domination, stealthily sending out her tentacles to envelope everything in her path. She was very well-behaved in the top garden, I am not sure quite what has come over her. So what started as a straightforward spring tidy of this area became a major overhaul as I attempted to remove as much of her offspring as I could (I am not naive enough to believe she will not reappear again before the year is out) which had weaved through and under neighbouring lavender and penstemon. She was banished to an area where she can do her worst without the risk of upsetting anyone, the offending runners were laid out on the paving to bake before I dare compost them.
ontheedgegardening 
I’m having a similar problem with Asters….
You turn your back for a moment and away they go!
Not very regal behaviour!
Achillea runs amok!
That read like a newspaper headline!
🙂
I planted one in a container one summer and of course nothing else was able to flower there except ‘her’…
I think “Queen” is probably a fitting name.
I just love the way you put ‘bits and bobs’ together It’s what I do but there is quite a bit of tutting from some of my designy friends.
It is just a different way of designing; as you probably only have extremely tasteful “bits and bobs” them they are bound to look wonderful when you put them all together.
I find I have similar problems with achillea – most of the time it behaves like a normal plant just bulking up slowly over the years and splitting nicely. In some spots though it takes over and is very hard to get rid off. I used it in a bed outside the kitchen 4 years ago and I have been digging it out ever since! Like bindweed and ground elder every tiny bit of root seems to be able to spread at the speed of light. Good luck with trying to contain it.
Glad I am not alone in this, it was a total personality change, in fact I had to check the label a few times just to confirm it was the same plant. I will be more wary in future.
I’ve had this too, I can’t remember the name but I planted one in a bed in my front garden it became a thug, I moved a lot of it to a place I would be happy for it to cover and it is well behaved!
I like your steps in the grass, Frances
In the end the plants just do what they want to do, which is a lesson I suppose. The steps are lovely but a bit treacherous, very steep and broken in part, I usually walk down the grass bank!