Yam daisies or murnong are really delicious bush tucker - a root vegetable that tastes like a pre-salted chip! The good news doesn't end there - they're also really good for you. But while once common around Canberra, they're pretty hard to find in the wild now.
But you can grow them in your own garden - specialist nurseries sell them and you can buy seeds online (albeit for a small fortune). They're actually not all that hard to grow, though I have learned the hard way that they do have some particular requirements.
Here are some lessons from my experience growing them for a couple of years.
First up, yam daisies demonstrate quite a lot of genetic variety, so some plants have very small roots, while others have larger fleshy roots, some even growing separate tubers like small potatoes.
Yam daisies have been decimated by grazing sheep over the past 200 years. It's possible that the best tubers were grazed out first, leaving some mostly smaller ones left. This is the remaining stock for us to start cultivating again to select for the biggest and yummiest tubers, as Aboriginal people may once have done. Bruce Pascoe's book Dark Emu covers how indigenous Australians practiced highly effective forms of agriculture for thousands of years before European arrival, including selective cultivation of yam daisies. It's a great read.
My interest in growing yam daisies was to see whether I could build up enough plants to allow sustainable harvesting for food, and to see if I could start selecting for larger root sizes (the plants I got initially had very small, albeit delicious, roots).
Yam daisies can be propagated from seed fairly easily. If you're able to ensure the pot stays nice and moist (covering your little pot with cling wrap works well so long as it's never put in hot sun) the seeds will start growing in about 1 to 2 weeks.
The plants seem to like quite moist soil, and I've had success with growing them in wicking pots and wicking beds in full or nearly full sun. In fact, this has been the only successful method for me.
Here are some lessons I've learned about yam daisies from experimenting with different habitats. Here are my top three mistakes to avoid with yam daisies - I know because I've made all three!
Don't shade them out
Yam daisies prefer a sunny aspect or only light shade, and will die from too much shade. I planted some out in a wicking bed that also contained broad bean seedlings at the back. The yam daisies were doing well in the bed until the broad beans grew large enough to fall in front of them and shade them.
I had thought that as an understorey plant, yam daisies wouldn't mind a bit of shade, but perhaps the shade was just too deep and the soil became too moist under there. Once smothered by the broad beans, they disappeared. I hoped they might resurface later as perennials often do, but they didn't. And unfortunately, no sign of them or their roots when I pulled out the beans later on.
This makes me wonder whether, in their remaining native habitats, yam daisies are out-competed by fast growing exotic species, especially those that cast a good amount of shade - plantains, sheep's sorrel, dandelions and so on. The only time I've seen a lot of them growing was after a site was cleared by a prescribed burn, effectively removing most of the competition. But the yam daisies didn't return the following year when there was a lot of other spring growth.
Don't assume that they can cope with dry soil just because they are natives
Another hard-learned lesson was when I decided to introduce them to a cleared area in our front garden. I figured that they must be able to cope with the our soil if they used to grow all over the Canberra region. The cleared area was near a tree but got dappled sunlight and is within the drip line of a large gum tree - perfect, or so I thought.
Some plants grew quite well here, but the soil was very dry. I watered and mulched it well, and then left the plants to their own devices. Alas, returning several weeks later, the plants had not thrived and were slowly dying. This could have been too much shade, but it was also clearly too little water. Interestingly I have seen yam daisies growing in very dry soil in our nearby bushland, but I guess it's easier for them to send down a tap root deep enough if they are grown from seed in that position, and not transplanted.
Collected seed is very appealing to mice and rats
My little collection of yam daisies in a couple of pots was going great in the back garden, and to my delight they were setting seed (seed set requires several flowers out at the same time, preferably from adjacent plants, to make sure pollination occurs).
I dutifully collected seeds and seeds until I had quite a collection, at least a hundred seeds at a guess, in a little plastic ziploc back that I stored with my other seeds in the garage. I was looking forward to propagating quite a collection and then selecting for those with larger roots.
You can imagine my dismay when I found a little hole in the bag one day and some mouse droppings inside the bag - and almost all the seeds had gone! Very few of my other seeds in the same place had been touched, making me wonder if the seeds are especially nutritious - for mice at least! So now, the very few remaining seeds I have are kept indoors in a Very Safe Place...
Given the yam daisy's apparent preference for both sun and moisture, I can't help but wonder whether this is evidence that there were better, more moist and deeper soils in the Canberra region prior to European settlement and subsequent land compaction and degradation through sheep and cattle grazing. I'll keep my eyes out this coming spring in our local bushland for any of their cheery little blooms, but you can't keep a gardening enthusiast down for long and I shall also be aiming to grow another batch in a wicking bed, this time without any competition from any other plants!
Growing conditions that yam daisies do like
My experience so far suggests that the most successful way to grow yam daisies is in their own dedicated, garden bed or pot, with light, friable, but consistently moist, soil mix. They need a good amount of sun and, especially, no competition from other plants. For me, this has meant good results in wicking beds, with a good quality potting mix. They seem to love a bit of seaweed fertiliser. Fire eradicates their competition, and they grow well after a burn, so the closer we can get to recreating those conditions when growing them, the more success we will have.
Why I care enough to keep growing yam daisies
In case you're wondering why I am still keen to grow yam daisies after all these setbacks, let me explain. They're local bush tucker, they're still disappearing from their former habitats, so the race is on to bring them back. They're also genuinely tasty.
A while back I harvested a root to try. It was small, no wider than my little finger. Uncooked it was a little bitter, so I zapped it in the microwave for a few seconds and even this rudimentary culinary treatment yielded something really good - sort of sweet like a new potato and a touch salty, with the texture of a potato too. Like a pre-seasoned chip - not bad at all!
They're also better for you than potato. The roots are particularly healthy because they contain inulin (like many members of the asteraceae family). This tastes slightly sweet and rich, but causes no spike in blood sugar because our bodies don't break it down into simple sugars, so it's fine for diabetics. Instead it feeds good bacteria in our guts, it's is a great prebiotic. I suspect we have barely reached the tip of the iceberg in terms of knowing about all of the yam daisy's nutritional benefits.
If you do a google search on yam daisies, you will see there is growing interest in this plant, including bush land regeneration projects (with ongoing research on the best conditions for its growth), cultivation and breeding programs, and gourmet chefs can't wait to get their hands on it.
Want to grow the next super food in your own back yard? Maybe we should all be growing yam daisies.