PLANT OF THE WEEK #21: Persicaria affinis

I stood there gazing at the Purple-leafed birch grove freshly planted not 12 months after Black Saturday had levelled my garden.

Planted in burnt, organic poor, compacted soils in a gravel garden, the birches needed a groundcover layer to keep the tree roots cool and the weeds down. I wanted a maintenance free layer to keep the grove looking simple and uncluttered.

Ivy was a no-no, and boring too. Star Jasmine – been done a million times. Epimediums were a maybe. They would grow well but I wanted something that needed not an ounce of care. Persicaria affinis was the choice.

A native from Tibet through to Kashmir, this plant is found in open meadows up to an incredible 4800m but is surprisingly just as happy at sea level. The ever fluctuating botanists have changed the name so many times I’ve lost count.

Now it is called Bistorta affinis. Before that it was Persicaria affinis, before that Polygonum affine! Let’s settle with Persicaria for now as that’s what it is currently sold as.

A mat-forming perennial that roots along the stems, P. affinis forms a dense carpet of narrow elliptic leaves with fine toothed edges.

These emerge in spring a fresh green and age to darker green through summer. By early December lovely cylindrical flowers on 20cm stems of a light pink darken to deep rose pink before finally reaching an almost red. Hundreds upon hundreds of flowers per square metre of different colours create a wondorous effect. The autumn foliage turns a rich golden orange before turning a bronze russet colour. A real four seasons perennial requiring minimum to no watering and a simple mow on a high setting to remove old flower stems in late winter.

Planted on mass under trees or used as carpets along gravel path edges or even a lawn substitute (yes you can walk on it), it’s a perennial for any and every garden. My original planting is now 10 years old and has never been weeded. I have a little shrug of satisfaction every time I walk past it.

Matt Reed is co-founder of wholesale nursery Antique Perennials in Kinglake, Victoria. Follow @antique_perennials


  1. This is a plant I grow and love – but it has never grown with this reported vigour here in the UK. How many plants to begin with, I wonder??

    1. 5 per square metre will fill it within 12 months although we do have much longer grwoing season than you do,

  2. This plant sounds too good to be true. I love it. I grow the common Persicaria Red Dragon which is almost weedy in my garden but haven’t seen this one. Where can we purchase, Ive got so many areas I’d love to try this.

    1. you can check our website for your nearest stockists

  3. I used this in a garden I installed almost 2 years ago, it impressed the hell out of me. As a shade-loving plant that flowers prolifically it’s simply one of the best for Melbourne. It’s a crying shame it’s not more widely known and used.

  4. A question. Is this a garden thug? Does it romp into areas where it is not welcome and then difficult to remove?

    1. No not a thug at all, it can easily be rmoved by cutting the stems with a spade and simply lifting it up.

  5. I’ve been in two minds about this plant forever. Not sure why. I think it’s that little leaf/little flower thing in which the flower spikes are so dense, but so little, that they felt like they only had impact on a small scale (like you lovely title pic), and became monotonous when seen en masse. But then I see how you’ve planted them under the birches, with the carpet just interrupted here and there with the bergenia, I can’t imagine a better plant for the job. It’s scary how often plants are undermined by poor usage, and, on the other hand, how your thinking/prejudice can be entirely reframed by seeing a plant used well

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