I choose a different Salvia each year, and so far they have all done exactly what I wanted, filling the 1 metre square space perfectly. I have grown Salvia leucantha, both white and mauve, Salvia 'Waverley' and several others. All perfect. None have come through the winter, although there is always a chance, so I leave them in place until spring.
And then, this season, I chose 'Megan's Magic'. I had good reasons: my daughter's name is Megan, and the flowers are intriguing. They are pure white with a deep purple, almost black, calyx, on long stems. The foliage is nice too: the large leaves are a pleasant grey-green.
I planted it and it grew modestly through summer, until it was a nice mound, with the first flower buds about to burst. Then I went away for a week. When I came home, a monster confronted me. In this shot it looks nice and unassuming, almost hard to see in the middle there in front of the Buddleia. But the scale is deceptive.
(I apologise for the quality of this and the remaining photographs in this post: I think there is something wrong with my camera, as none of the shots seem to be sharp, despite the bright sunlight)
This thing, described by the growers as "A compact form. Height 80cm, width 70cm", is now 1 and a half metres tall and 2 metres wide. And it has about 6 weeks left to grow. Compact it isn't. The stems are splayed out from the base, and so far it has swallowed all in its path: a rose, a lavender, a Teucrium, an Agastache and a Penstemon. It is also completely shading out the plants behind it.
It is very handsome, and I love the colour in combination with Artemisia 'Powis Castle' and the Buddleia davidii 'Black Knight'.
But it is just too big. I'm not sure whether to leave it in its splendour and let the other plants fend for themselves, or try to cut it back to give them room to breathe, which might completely spoil its effect.
It is a beautiful monster, and I will certainly grow it again, but somewhere else where it can flaunt itself without bullying its neighbours.
Have you had a similar experience with a plant that has turned out to be a monster?