Seasonal Garden - Queensland Arrowroot

I first came across this plant in the Green Harvest Organic Gardening catalogue. I like trying out new plants and this one seemed very interesting, so I invested in 5 tubers and planted them in the ground. Little did I know what to expect, but I was soon to learn.

Plant Name - Queensland Arrowroot - Canna Edulis

Other names used for this plant include: achira, achera, dong rieng, edible canna, ganyong, sakhu chin, zembu and maraca.  The plant originated in South America and is from the same family as the Canna Lilly.

Whilst in the tropics, subtropics and warm temperate climates this plant can grow all year round (perennial), for me here in south west Queensland in my semi arid climate with occasional winter frosts it is more herbaceous in nature, disappearing below the ground in winter to re-shoot again in the spring once the soil has warmed.

Each rhizome will form a clump and for me, usually grow to about 2 meters, with  thick fleshy stalks and huge bright green leaves.  Once a clump is well established I have found that it is able to cope well with our high summer temperatures.  This is a very hardy, productive edible plant in my garden.

Rhizome or seeds?

I grow my plants from rhizomes, which I dig up each year harvesting the tender young rhizomes for the kitchen and replanting the older more fibrous rhizomes back in the grounds. When replanting make sure you leave about 30cm spacing between the rhizomes to allow the clumps to form.  I also cut back the fleshy stalk and leaves, leaving about 30cm of stalk.  I replant my rhizomes in late autumn, before the first frosts arrive and whist the soil is still warm enough for the plant to focus on growing roots not fleshy new top growth.

If you are in the tropics, subtropics and warm temperate climates you can of course, do this all year round, as in these climates this plant is perennial.

This is not the only way to propagate this plant however, you can sow its seeds. I have not tried this method, but I understand you need to soak the seeds in hot water (not boiling) until they have swollen (about 24hrs). The seeds can then be sown into pots and keep in a warm sunny spot until big enough to plant out once the danger of frosts has passed.

Soil

I have grown my arrowroot in both the ground and also large containers.  The first time I grew them in the  ground, not doing anything with them for about 3 years.  The clumps  became well established but started to run out of space.  At this point I had to dig them up which proved a little difficult.  Since then I grow my plants in large containers, digging them up each years and replanting what I want for next year.  This way they are easy to harvest and don't get congested.

The soil that I use is a sandy loam with added organic matter to help with water retention, however the first three years they spent in the ground I did not add any organic matter, nor did I add any compost.  They pretty much looked after themselves with no fuss.  They do grow better though if you can incorporate organic matter in the soil as they are large fast growing plants and a little TLC will reward you with plenty of tender rhizomes for the kitchen and good top growth.  I dig my soil over and add composted mature into where I am going to plant them, this method gives me good production each year.

Watering

This plant doesn't mind a bit of water.  I irrigate mine due to the semiarid climate I live in.  It will tolerate dry periods, but if you are wanting tender rhizomes for the kitchen, ensuring that the  plant does not dry out is a good idea.  If you receive good reliable rainfall, you may not have to supplement the watering.

Position

A warm sunny spot suits this plant. It will tolerate some light shade, but I grow mine in full sun.  If you have frosts, you will find your top growth dies back below the ground.  If you have hard frost I would recommend mulching over with something like sugar cane mulch to protect the growth tips of next year's plants.   If you do this, pull back the mulch in spring once the risk of frosts have gone to allow your soil to warm up and encourage the new spring growth.

Pests and Problems

I have had no problem with any pest or diseases. So far trouble free.

Harvesting

I harvest my plants at the end of Autumn before the first frosts. Choose the new, tender rhizomes for the kitchen. They break off easily from the last year's rhizome.  If you try and use the previous year's rhizome in the kitchen you will find them very fibrous.

Storage

I wash and store my rhizomes in the crisper of the fridge, though I have also stored them successfully in containers covered in damp (not wet) soil, somewhere cool and dark. That way you will leave your crisper free for other less hardy produce. The only problem I have found with this is that I am less likely to use them in the kitchen - out of sight out of mind!

Final Points

This plant is so much more than edible rhizomes for humans, here are some other uses for this plant:

1. Leaves can be fed to chickens, goats, cows and donkeys. 
2. Tubers can be cooked and fed to pigs. 
3. Provides chop and drop mulch
4. Used as a weed barrier
5. Windbreak 
6. Living fence / barrier
7. Provides shade
8. Provide a microclimate - Cool an area down / warm and area up
9. Create habitat
10. Provides compost / worm farm material

This is a great plant, easy to grow, keeps giving and very versatile.  In follow-on blog post I will look at how to use this plant in your cooking.