Yams in Melbourne - Japanese or Chinese Yams are the easiest to grow

White Yams Dioscorea alata are very beautiful plants and I've been working out the best way to grow them down here at Lat 38 south. All this time though I've also been growing, but kind of neglecting, another Yam that is in fact a lot easier to grow than White Yam, Chinese or Japanese Yam, Dioscorea opposita or polystachya (depending on the source). These are the long, white yams sold in various markets and which I embarrassingly once mistook for Cassava and used for a student prac.
 
Chinese Yams have smaller more delicate leaves than White Yams and in that way their beauty is more subtle. The actual yams are very long and skinny and probably best grown in deeply dug, raised beds if you are serious about production. See this man taking them out of a purpose-built planter box:

Their main virtue in terms of ease of cultivation is their cold tolerance, more specifically their ability to overwinter in cold, shaded, moist soil. I have pretty much proved now that White Yams can't do this in Melbourne and will rot if not lifted and stored. They will will only re-shoot in spring in a free-draining, open sunny site (more on that in another post).

But Chinese Yams ride through it all with no problems and do not rot at all. Their foliage also persists long into winter and still looks good too even after a few cold nights. This is a plant that deserves to be grown more commonly as a deciduous herbaceous climber with the added bonus of edible tubers.At present they are not sold in nurseries and you can't buy them from such pioneers of alternative edibles as Greenharvest or Isabella Shipard. I'll work with my students at Burnley this year to see if we can change that in some way.

If you're from southern Australia have a look at the following video of a Chinese gentleman growing a commercial yam crop in the (relatively) cold Otway Ranges south-east of Melbourne. Quite extraordinary, I'd love to meet this guy.

Finally, a shot of Chinese Yam foliage from my garden this year:

Chinese Yam growing up a trellis with Brazilian Spinach and Mushroom Plant growing underneath

 

 

Growing Cassava or Manioc in Melbourne

Cassava is one of the world's most important staple foods, at number five after corn, wheat, rice and potatoes. It tolerates drought, heat and infertile soils and produces starchy roots and edible leaves. It's also easy to propagate by cuttings. As a member of the Euphorbiaceae it's no surprise that Cassava contains cyanide and therefore it must be thoroughly cooked to remove the hydrocyanic acid. It's also a beautiful plant and there are ornamental varieties available apparently in the United States, which I'm fairly confident don't exist in Australia although I will double check this in the near future. I've been having a go at growing Cassava in Melbourne for the last two years and unlike some other tropical plants that are surprisingly productive at this latitude, Cassava seems relatively marginal. 

Cassava it seems needs more heat than Melbourne's growing season can provide. However, with access to the glasshouses and polytunnels of the Burnley Campus of the University of Melbourne, I have been able to grow established plants ready for summer planting. Last year these grew well in the Burnley Field Station and looked very attractive growing amidst yams, taro and cranberry hibiscus. I didn't try the leaves but will do so this summer. I dug up the roots in late autumn and production wasn't great but they were delicious nonetheless. As various sources promise, Cassava roots freeze well and a small bag of pre-cut frozen roots plunged straight into boiling water worked perfectly during winter.

Cassava in the middle with the palmate leaves

On a final note, I've been working on a great project on the Richmond Housing public estate with my student Lia De Gruchy, Kath Orsanic-Clark the Urban Agriculture Facilitator from the City of Yarra and with Bernadette Jennings and Andrew Williams from the Department of Human Services at the estate. The project is a story for another time but in short we recently planted some Cassava there and one local resident was astonished to see four Cassava plants freshly plonked in the ground. She was originally from Indonesia and told us that many members of the Indonesian community really miss Cassava leaves which she said taste like silverbeet. Many plants such as Cassava could be grown in nurseries for sale to
communities whose gardening interests are usually ignored. Just like tomatoes, egg plants and cucumbers there is nothing inherently difficult in growing heat loving plants in greenhouses in winter ready for the spring, summer, autumn growing season.

Eating Sweet Potato leaves - excellent summer spinach

Sweet Potato plants are excellent ground cover plants once established because they sprawl prolifically and tend to close any gaps in the 'canopy' of their foliage. This stops weeds pushing through their leaves. This mass of foliage look great too and for this reason there are many types of ornamental sweet potato varieties with different leaf shapes and colours. I've planted crop and ornamental types this year and they all look beautiful.

Perhaps more interesting and exciting is that Sweet Potato leaves (and the young stems) are edible and nutritious. They have a relatively high protein content and therefore complement the low protein content of the tubers. I have bought Sweet Potato leaves from the Asian section of the Preston Market, sold alongside Kang Kong, Rau Om and other Asian greens. The link below takes you to a paper called
Nutritional and Medicinal Qualities of Sweetpotato Tops and Leaves from the extension service of the University of Arkansas. It rates the leaves very highly indeed.

http://www.uaex.edu/publications/PDF/FSA-6135.pdf

But do they taste any good? The answer is yes. The can be cooked as a simple boiled/steamed spinach to become a green blob of at the side of your plate, or try the more adventurous recipe below from page 156 of the book Cooking with Asian Leaves by Devagi Sanmugam and Christopher Tan:


Sweet Potato Leaves in Coconut Gravy

Ingredients
Sweet Potato leaves
Oil
Shallots
Garlic
Ginger
Lemon Grass
Red Chillies
Turmeric powder
Coconut Cream
Water
Salt

Method
Pour boiling water over the sweet potato leaves and let it stand for about 1-2 minutes. This is to get rid of any sap that is sticking to the leaves.
Strain water and rinse the leaves with cold water to prevent it from overcooking. Heat oi. Saute the shallots, garlic, ginger, lemon grass and red chillies until aromatic and soft. Add in the turmeric powder, coconut cream, water and salt. Bring to the boil for 2 minutes, stirring frequently. Add in the blanched leaves and mix well. Serve with rice.

Here are some photos of various sweet potato leaves from my garden including some ornamental types which I've planted in the front yard.