A few years back I was checking out a stand of ornamental grasses at Chelsea Flower Show and was curious about the range of unfamiliar (and mostly evergreen) grasses on display. I liked them well enough – particularly when grown as well as you’d expect anything on display at Chelsea to be – but couldn’t help but wonder about the management of them, long term, which is generally much trickier than that required by deciduous grasses.
Wondering where to start in conversation with the exhibitor, I asked him which of these grasses he considered to be the most underused and underrated of them all. Without hesitation, he stated that it was Poa labillardieri. I was flabbergasted. And then a bit disappointed.
We’ve all seen Poa lab (as we all call it, in order to avoid the embarrassment of forgetting, and therefore mispronouncing, the order of ‘i’s and ‘e’s in those last few syllables) looking appalling along freeways in Australia – the very essence of the deeply flawed but still widespread belief that Australian native plants don’t require maintenance. After three or more years a plant of Poa lab without any maintenance is at least 70% dead matter (‘straw’ as it’s known amongst its industry acquaintances), and 28% half-dead matter. At that point in life it tends (in garden settings, or parks, where it’ll get trampled or squashed) to become brittle, so great chunks of it fold over and eventually shed, winding up looking like the patchy wig on the Gerry Gee doll with which my much older brother terrorised my childhood. Hence my flabbergastedness.
Poa lab looking very nearly – but not quite – its worst 
Poa lab looking as you’d expect after three or four years. It’ll need some action at some point soon to maintain this amount of green
That turned to disappointment as the inevitable internal question started to formulate “If Poa lab is the best of them, how bad must the others be?”
Given all that, I did ask the guy pushing the plants how Poa lab is best treated in Britain, in order that it should look its best in perpetuity. He told me that it should be handled like most of the other grasses, and given a hefty hair cut – virtually to the ground – in spring. Frankly, I don’t see how this could work. Deciduous grasses can be cut back to stumps anytime after their foliage has died in autumn through until the new growth emerges in spring, as the plant has clearly finished with it and retracted a high proportion of the nutrients it needs for regrowth. The same isn’t true of evergreen grasses. They’re not necessarily equipped to fully replace themselves every year. You certainly can’t treat Poa lab like that here in Australia. Nevertheless, I really wanted to believe this guy, and to that end wondered if perhaps the colder/more emphatic winter in Britain forces a different growth pattern onto it, allowing for this treatment.
In our climate, my understanding is that Poa lab is largely a winter growing grass, or at least a cool season grass. Some gardeners in our local Council have told me that they’ve had great success with cutting it hard in Autumn. I should have asked whether they do this annually, but didn’t.
This pic above shows a friend’s garden where we used Poa lab extensively, about three years ago, and in a really prominent place in the front of their house. These were cut back last Autumn for the first time, and are recovering, but not rapidly. With that pace of recovery, you certainly wouldn’t want to cut them every year.
The question remains as to whether they’d have recovered faster if they’d been cut back every year from when they were young plants. These same friends had cut back much younger plants elsewhere in their garden at the same time, and these had recovered much faster but were not yet in full flower. They were, however, planted in much better soil, and this appears to make a great difference to the rapidity and extent of their recovery.
These sorts of management questions are poorly understood with most of the evergreen grasses. We’ve all seen patches of the lovely (when young ) Festuca glauca that has been shaved back hard in an attempt to restore its youthful freshness, only to result in patchy tufts that put me in mind of a 70’s comb-over. Likewise the carexes (which aren’t actually grasses, I know, but are used in exactly the same way and present the same problems). Why don’t those selling such plants provide us with guidelines/principles about how to keep them looking fresh in perpetuity – or at least for a reasonable number of years? In a garden setting (as compared to one in which these plants are used en masse), I don’t bother trying to manage the older plants, but simply replace them every three years or so with inevitable self-sown progeny.
There’s other considerations as well that I’m reluctant to start on (given that they might take me a few thousand words to articulate) that deal with the idea of inherent modesty in a straw-filled plant like Poa lab and it’s consequent usefulness as a matrix/background plant for other modest, low-showiness-rated Australian native plants. The cleaner, more highly groomed presentation of the deciduous grasses on the other hand, might simply be a better match for the showier exotic perennials. Maybe we’ll deal with that huge question some other time.
Meanwhile, while the questions remain, in my own garden I’ll be sticking largely with the much-easier-to-manage deciduous grasses. But I can’t shake the conviction that I’m missing out on something..
I quite like Poa, especially the bluish variety sometimes offered by Lambley Nursery. I generally cut them nearly to the ground shortly before the seed ripens, just to stop them from self seeding too enthusiastically. They always re-grow very generously. I had in the past transplanted huge clumps of them in winter, and, after sulking for a few months, they kept on thriving. Have never been watered, nor fertilized more than a very light dusting of low phosphorus fertilizer I spread all over the garden in early spring.
So when is that, Adele, that the seed ripens? When do they normally get the haircut?
I told the exhibitor about Lambley’s bluer named form ‘Suggan Buggan’. He was very interested, as there’s been no breeding development over there. We also have the form ‘Eskdale’ available here which claims to produce less ‘straw’ but the real question is how to manage it in the long term, not just putting off the inevitable problem, isn’t it..
Not 100% sure, but I try to cut them when the seedheds start looking sand couloured, and start shedding stuff when touched. Not very scientific, I know, but it probabaly varies anyway, depending on the season, the zone, the soil, the aspect, etc… I had also cut them down way after the seed ripened, the recovery was still OK, but you can expect lot s of new little tufts of grass on your paths then.
I’m guessing that must be mid-summerish. Glad to hear that that can work, but I also know that in my cool climate where a long winter downtime is forced on us, I don’t want to be cutting anything back in mid-summer – don’t want any bare patches then. As you say, it will all depend on climatic zones, and is likely to be different all around Aus.
I’m not a fan of native grasses in gardens or otherwise cultivated. the ones near us (NSW Southern Tablelands) are natural and I think of them always as straw coloured. When they do that clumping and folding over themselves they are forming homes for tiny marsupials, lizards and snakes (hopefully not together!!) – maybe even small birds?. Occasionally the plants are mown over with the tractor, sometimes they’re burnt out but this is never deliberate action to encourage new growth. It looks to me that the domestication of the Australian native poa is still in its infancy and the questions you raise here will surely help the process. love your posts.
I agree, Sally – still very much in its infancy. No doubt this Poa has its place in its ‘unimproved’ form, but only a very limited place. It’d be nice to be able to introduce it into other company as well. That can’t help but sound like appalling plant snobbery, but it’s more about understanding the inherent modesty of any plant and then placing it in complimentary company, isn’t it..
Stipa gigantea is an evergreen too. It does, however, produce an abundance o new growth that covers the accumulation of straw. I manage to just strip out all the old stuff from underneath at the end of winter so the new leaves can arch gracefully. However like so many grasses this Stipa doesn’t perform well in warmer , drier climates. I have had Ampelodesmos mauritanicus now for 9 months. I saw it growing all over the hillsides of Sicilia so i am hoping it will be drought tolerant. It is , of course a plant of much greater stature than Poa lab.
There are so many new grasses coming on the market, evergreen and deciduous . The next few years will be a phase of watching and learning as we experiment with their use
Yes, Stipa gigantea does seem to escape the standard criticisms of evergreen grasses. The fact that it’s relatively easy to groom is one reason, as you say. One more is that its whole point is its flowers, and these sit so high above the foliage that you don’t even look at the foliage. The foliage can be almost buried in surrounding planting, if you want, and those flowers still float and sparkle up at about head-height. Another reason is that it’s one of the few grasses that is emphatically an individualist – looking best on its own, or if clumped up, done in such a way that you read it as one large clump. That makes its few sins much easier to hide, compared with those grasses that we tend to use in huge sweeps.
Have to agree with Adele – Lambleys ‘Suggan Buggan’ which has the best intense blue colour due to its flat, rather than the usual cylindrical leaves, it’s a beauty. I cut mine to neat stumps at least once a year, usually in Setember or early October and they bounce back quickly, with new shoots appearing the next day, looking respectable when we usually have the garden open on the second weekend in November. Avoid the worst of the summer heat to cut them, because this can weaken them or worse.
This aligns perfectly with what the exhibitor said. Maybe it’s that simple after all.
Dang. I just weeded about 20 seedlings out of my raised vegie beds. If I’d thought of it earlier, I’d have transplanted them to a holding bed and tried various cut-back times to see if the same thing is possible here. Certainly with our winters, I don’t like the idea of an autumn cut-back, as they just wouldn’t recover until well into spring, and that makes for an excessive downtime. That quick turn around in spring is much more workable.
I cut down my plants of the very beautiful Suggan Buggan in early spring each year and so far they have bounced back happily. Not so pretty for a while but the short back and sides spiky effect grows out quite quickly. My only problem with it when in full flower is its habit of leaning on its neighbours for support after heavyish rain and being reluctant to fully straighten up again. When the planets align successfully the purple haze of flower heads blend charmingly with the lipstick pink of salvia involucrata. I’ve tried the blue fescues in several places but without much success, they generally squat on their cushion of straw and look downright miserable.
Poa sieberana seems to perform better for me than the blue fescue. At least in the time that I’ve grown it, which is three or four years, it’s still looking good, and it does not require much maintenance.
Your experience looks like it aligns with Michael Cooke’s below, with the spring cut-back. Gotta give this a go with young plants in good soil.
I’ve also witnessed the problem of the leaning on the neighbours – seems like these Poas are yet to really learn their garden manners – but then I suppose we can’t expect anything more from a wild plant, without any deliberate improvement (beyond the selected-from-the-wild ‘Suggan Buggan’).
And I love your ‘When the planets align..’ We should author a book and call it that – pics of all those things that happened only once by some happy accident of weather or other timing influence, and that we try and replicate for years after, never losing our conviction that maybe, just maybe, this year the planets will align again
I was fascinated by this discussion on Poa. I try a different approach. I have lots of Poas in my garden. When they partially die off at the end of the summer, I get a thick pair of gloves and pull off all of the dead bits, thinning them out, rather than cutting them down. It seems a bit cruel, but it leaves the happy newer green bits in the centre to flourish over the winter then look really lovely again by spring.
Thanks Kass. Most gardeners I know use this very method for ‘grooming’ Stipa gigantea. I don’t know of anyone that uses it for Poa, but it’s good to know that it is satisfactory, and to add another option!