PLANT OF THE WEEK #15: Poa labillardieri

Having laden this Plant of the Week feature of The Gardenist with plants about which the authors could all enthuse unequivocally, I thought it was time to include a plant about which I’m in two (or maybe three, or four) minds.

So here goes.

Poa labillardieri.  You know it – it’s that grass that’s too often used in large masses on the edge of freeways, and is best remembered for its remarkable ability to catch and hold old chip packets and, with the build-up of ‘straw’, look 90% dead.

Makes you want to grow it, eh?  

But then, a couple of years ago, we were being shown around some fabulous naturalistic planting in a German cemetery, and I spotted a grass of lovely bluish hue, surrounded in a fine mist of golden flowers, paired with mauve Aster x frikartii.  There’s no way of getting even this far into the story without giving away the point.  I asked the designer (the yet to be internationally acknowledged Harald Sauer) which grass it was.  And by now, I don’t need to tell you.  

This links with another encounter, 10 years earlier, at Chelsea Flower Show, when I asked the exhibitor of many ornamental grasses which he felt was the most under-rated, and, without hesitation, replied ‘Poa labillardieri’.  I still wonder if I heard him correctly, though I asked him to confirm at the time.

As I write, it occurs to me that if one decided to grow almost any herbaceous perennial without any grooming or cut back throughout its life, and therefore not removing the annual accumulation of dead matter, it’d look as bad as a freeway-side Poa.  So we probably shouldn’t think any less of it for that. 

In its favour, Poa lab (as it’s familiarly called (I was going to say ‘affectionately called’, but I’m not sure that there’s a real lot of affection involved)) is an incredibly tough grass, largely indifferent to soil type.  In many parts of Australia it will thrive without any supplementary water.  It forms a dome of foliage to 60-70cm, and the flowers can hover beyond the foliage to a total of about a metre.  The distinctness of the tussock form is an important part of its contribution, so it should be planted with sufficient spacing to achieve a pattern of repeated hummocks, rather than creating an undifferentiated blanket covering.

For me, the single most critical aspect of its integration into mixed planting is a recognition of its inherent modesty.  Some grasses can stand proud amongst flamboyant perennials.  Poa lab isn’t one of them.  To my mind it looks best when mixed with other really modest plants of contrasting form – think Poa lab with other native strap-forms like Dianella, Lomandra, or non-natives like NZ flax, or alongside clipped domes of Westringia or Correa.  Having said that, how I saw it managed OS makes me think that maybe Poa lab is capable of dancing on a somewhat more glamorous stage that I’ve ever provided for it.

I wrote a piece for the blog about Poa lab back in 2013 that led to a fabulous conversation about various readers’ ways of managing it, which you can access here, and then add your voice to the discussion below on this new thread.  Or if you’ve got anything to say in its defence, or its condemnation, please add that below too. 

I can’t help but think that one day I’m going to find the key to using, placing and managing Poa lab that makes me see it in a whole new light.

Discussion

  1. Thanks for this post Michael. I love this plant but have felt the same about it in the past. What do you recommend as the best maintenance to keep it looking it’s best?

    1. Such a fabulous grass. To keep it looking alive (it rarely dies, it seems) I prune mine mid Autumn (May-June) before new growth sets in and seed heads are looking a bit rangey. I cut back to strong to about 10 cm. It returns bright green and clumpy within weeks. I also divide it after a few years, and because it self seeds in my garden, I either give it away or compost it. Wonderful for blue tongues and as a garden design softener, in a hard to please garden.

  2. I love poa lab and have a number of them growing amountst densely planted natives such as pimelea, correas and boronia. They are the only grass species I have planted in this garden and grow with vigour to about 90 cm height each year. I think they look great when they dry off and everything around them is still green.
    In my experience, the trick with cutting them back is all about timing. The perfect time is after the first decent post-summer rain (in an un-irrigated garden.) Some years this is in autumn, but I’ve had to wait until winter too. There needs to be enough soil moisture to allow them to bounce back strongly. If you cut them back before there is good soil moisture, they may not recover – I have learnt this the hard way!
    I use shears to cut them down to about 10 cm off the ground. (My children collect all the offcuts to use as cubby house thatching!) In an autumn as good this one has been, I was able to cut them all back in early April and, as the soil was still warm, they were covered in fresh green spikes in 24 hours. They can also readily be divided and relocated, but need good moisture for this also. Other than an annual cut back, I do nothing to them and they give me so much joy in return!

    1. After reading your post on Poa lab, Michael, I checked out my clumps distributed around the garden. Right now they are tall, elegant, upright and providing great contrast to the things growing around them. I think, as Hilary mentioned, timing is everything as far as their care and maintenance is concerned. I’ve learnt that the hard way too. I have them planted with other Australian plants, as well as Euphorbia. I’m experimenting with them among Perovskia this year in a rocky, dry spot in the garden, largely because I really like their flower heads swaying in the breeze (ok, sometimes it’s a ferocious, dry north westerly!)

  3. I’m so glad you’ve written again about Poa lab, Michael. Your earlier post about your encounter at Chelsea inspired me to give it a crack in our garden. I’ve found it grows quickly from seed, so have been getting my stock up ready to go in this year, and using the intervening time to look at how it’s used locally, in gardens and reserves. I’m thinking of mixing it with perennials (sedums, euphorbia, asters, pycnosorus globosus, and probably too much other stuff). This post has given me plenty more to think about – and great photos for inspiration. Really looking forward to seeing what emerges!

  4. Agree with all the above comments, a frustrating plant, that can easily be the best grass in the garden…sometimes. As everyone has pointed out above, the timing of the cut back is key. No idea why all labels and books suggest a Spring cutback, this has achieved nothing for me but sad weak growth. The Autumn cutback is key, and yes, a cut back with moisture in the soil. This year I did it 2 weeks ago (mid NSW), and they have already put on significant fresh green growth. I am using this and Lomandra “Lime Tuff” as the base grass palette.

  5. Quite simply one of the best grasses for a no irrigation planting in SE Australia, in my opinion. I included it in my nature strip grassland planting for its height, in order to discourage foot traffic from cutting across the strip. It’s performed beautifully in that regard. While its winter/spring green phase looks lush and pleasing, my favourite stage is always the oaten brown tone it turns in January and February. I order to jazz it up last season I planted Drimia maritima amongst it and the combination of the straw-coloured poa and the striking inflorescence of the squill has been one of my greatest plant combo triumphs to date. A very nice match.

    Combining it with other native grasses, especially the lower-growing species of wallaby grass, is a winner too. The wallaby grasses hold their glumes for months after the seed has dropped and they catch the afternoon light just beautifully.

    In terms of maintenance, I cut them back late Feb with a bread knife – gather up the foliage and slice off just above ground level. Literally a minute per plant.`

    1. This is great advice, James. How long does it take (in a normal dry year) for the plants to re-clothe themselves with foliage, after cutback? Also interested in your opinion that this is one of the best for no irrigation. I couldn’t help but wonder if its ubiquity was more to do with its availability than its quality

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