Dividing Perennials – to increase your plant stock

Confined to the garden, looking for jobs to do and unable to pop to the garden centre for new plants, the COVID 19 pandemic has forced me to do more dividing of plants then I would perhaps normally do. That’s no bad thing as dividing perennials is a brilliant, cost-effective way to increase your stock and it refreshes plants which might otherwise outgrow their space, start encroaching on other plants, or become a bit tired.

This weekend dividing perennials was top of my Spring jobs list and I divided two plants – the acid yellow Yarrow Achillea Moonshine plus an Anemone, which I think is Hupehensis ‘Praecox’ . I’ve had it such a long time that the label has long gone and I can’t be sure. Anyway, it’s a pale mauve. Both had been growing in pots for years and in the case of the Achillea it had outgrown the space, whilst the Anemone just looked all wrong in the blue pot I had it in. It was a waste of a good pot and a good Anemone!

I have a newish bed in the garden with some dappled shade and thought both plants would work nicely in the space, and be a cheap way to plug a few gaps. The Achillea prefers full sun, but I’ve had success with them in the past in slightly shady spots.

While I’m a fan of dividing perennials, I’m always slightly scared that I might kill the plants in question. So, I always remind myself of the general expert advice and try to faithfully follow it. In essence this is:

Dividing perennials

• Timing – Divide plants in Autumn or Spring, when they’re dormant, or growth is just kicking off – and certainly not when the plant is in full growth with lots of flowers to sustain
• Lifting – Lift the plant by loosening the surrounding soil, taking care not to damage its roots
• Shake off as much loose soil around the roots as you can and remove any obviously dead bits
• Dividing – If the plant has fibrous roots, the experts suggest putting two forks back to back near the middle of the plant to divide it. To be honest most of us don’t have two forks, and if we do, we can’t manipulate them in this way without injuring ourselves! So I use one fork and do a lot of reasonably gentle waggling of it. I then wade in with my hands
• If a plant has fleshy roots, the experts suggest you divide with a spade, again making sure you can see the shoots so you aren’t needlessly damaging them
• How many – The number of times you divide the plant will depend on what it’s capable of being divided into. Obviously every sub-plant you create needs to have at least one healthy bud and its own share of roots. Also bear in mind that if you divide down into masses of tiny sub-plants, it may be some time before each plant is making a substantial show

Replanting the divided plans

• Planting – It’s common sense really that the division of a plant is putting the plant under a bit of stress, so you want to minimise this not least by replanting your new plants as soon as possible. You don’t want the roots to dry out
• Dig holes for your new plants that are as deep as the depth they were in before
• As when you are planting anything, make sure you are allowing enough space around it for it to grow
• TLC – I also give mine a bit of a feed by mixing a handful of fish, blood and bone general purpose feed into the bottom of the holes – to settle them in and help them on their way
• Spread out the roots before filling in the holes
• Firm the new divided plants in gently into their holes
• Then give them a really good drink and keep them well watered until they settle in

In the case of my two plants, I divided them each into four – I could have divided them more than this but quickly wanted reasonably substantial looking plants in the bed.

There’s always a slight panic when dividing perennials – especially with the Achillea, which looks a bit droopy and scruffy after division. But the next day the plants all looked very perky. I now have eight plants, where I before had two, and I’ve freed up two pots for, yes you guessed it, more plants!!

Perennials you can divide

This list isn’t exhaustive but in Spring you can divide sedum, hemerocallis, achillea, anemone, hosta, primroses, salvia, verbenum, agapanthus, delphinium, eryngium, lychnis, hardy geraniums and crocosmia to name a few.

It’s worth noting that some Spring-flowering plants, like irises, need to be divided in the Summer, after they’ve flowered. It’s logical really, as you don’t want to be putting a plant through the stress of division in Spring, at a time when it’s producing its flowers and doing its stuff!

Anyway…happy dividing.