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Lifting and dividing


by James Alexander-Sinclair

Casting an eye over my borders recently, I noticed that some of my plants were badly in need of splitting.


Lifting and dividing a congested clump of ornamental grassI'm sure it hasn't escaped your notice but, just in case it has, I feel it my bounden duty to point out that there are all sorts of things quietly growing out there. The months of inactivity are drawing to a welcome close; it's time for a general girding of loins and a flourishing of hoes.

Casting an eye over my borders recently, I noticed that some of my plants were badly in need of splitting. In particular need of attention was a fine grass called Calamagrostis x acutiflora 'Karl Foerster', which looked less like a happy clump brimming with energy, and more like a cross between a Polo mint and a shabbily maintained monk's tonsure. All the growth has migrated to the edges. This is something that happens to a number of herbaceous perennials and is a strong indication that the time has come for a bit of division. (Although this sort of behavior doesn't help!)

To divide a plant, dig it up and discard the centre, as it is only fit for the compost heap. The healthy bits can then be split and replanted (using a sharp spade, a pair of forks back to back, or even an axe if the roots are particularly tough). I easily got nine plants out of my C. x acutiflora 'Karl Foerster'.

One of the best tips on division of plants I have ever heard regards mint in pots: I was told it by Kim Hurst from the Cottage Herbery at the Malvern Spring Show last year (the 2009 show, by the way, runs from 7-10 May; I hope to see you there) . Those of you sensible enough not to let mint run loose in your flower beds will have it in a container. You may have noticed that the centre is soon pretty barren and all the shoots are on the edge: if you leave it like that the plant will surely die, for it will have nowhere to go and a mint that has nowhere to go is a doomed plant. To revive the plant remove it from the pot, cut it in half and turn the outside edges so that they face inwards then replant in the pot with a bit of fresh compost. So simple.

The general rule is that early-flowering plants should be divided in the autumn, while late flowerers are better off split in the spring. I am off to check on my rudbeckias, heleniums and crocosmias.



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Gardeners' World Web User 11/03/2009 at 19:33

high ive got a nearly pot bound plant called so im told dont know if my uncles having me on ( mother in laws tongue) can i split it now its flowering at the moment sticky sappy flowers

Gardeners' World Web User 12/03/2009 at 14:53

I have michelmas daisies that have the 'need to be split' look - they are a bit like a fairy ring. Can I split these now and how deep are the roots; do I need an earth mover - they have been growing untouched for at least 15 years.

Gardeners' World Web User 12/03/2009 at 19:34

today i weeded and turned over the left side of my drive my daffss tulips and hiyasnth bulbs are flowering, but lasy september i made the mistake of planting them in huge clumps so i dug them up and spreaded them out more naturally will this harm them

Gardeners' World Web User 13/03/2009 at 16:42

The only plant I have with the tell tale polo effect is a flag iris taht badly needs sorting out. For some reason, all the other big clumps of perennials such as phlomis and assorted lysimachia are more like extra strong mints with no hole and no weakening. They do need a good sorting out but I hate to discard viable plants on the compost. As for everything else, I am waiting with fingers crossed to see what has survived our several snowfalls and temps down to -25C. It looks like several shrubs are gonners and no doubt the verbenas, assorted penstemons, sedums, clematis and all except the creamy coloured hellebores. and that's not counting teh treasures "weeded" by my husband when I asked him to clear some invading nettles. One can have too many "planting opportunities" sometimes. I also have a new garden helper in the form of a Tibetan terrier rescue dog who likes to dig the garden just a bit too much.

Gardeners' World Web User 13/03/2009 at 18:51

Thanks for the tip about mint. mine is exactly like that.

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