Growing Arrowroot

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canna edulis rhizome

Arrowroot is a name that is attached to several plants that have viable and sometimes commercial quantities of edible starch in the roots or rhizomes. They are all predominately tropical and have a cultural history where they grow.

We only grow one of the plants that fall under the banner of arrowroot, and as you will see, we find it a very useful plant indeed.

This article is based on Canna edulis, also known as Queensland Arrowroot, and this is the plant we grow here in the wet tropics of northeast Queensland, Australia.

It is just one of many plants we have in our yard, and it plays a small part in our permaculture design of the property.

To help with the flow, we have sorted the topic into common questions about the arrowroot, and we expand on each section with how we approach the plant from a home-grown perspective. So to get things started, how hard is arrowroot to grow?

Is growing arrowroot easy?

Growing arrowroot is very easy as it can grow in hot, dry locations with minimal water and still deliver a harvest at the end of the season.

The canna edulis plant is one of the plants we are guilty of neglecting at times. We could say that we share Mark Sheppard’s practice of sheer total utter neglect, or STUN, as he calls it.

We operate on the basic principle that if a plant needs our full-time support to grow, it does not apply to our long-term plans. We cannot spend our days playing wet nurse to delicate plants that could quickly just up and die at a moment’s notice.

However, as is typical with most plants, you get back what you put in, so the yield will suffer with neglect, and conversely, the yield will increase with good conditions. It is up to you how you approach it.

We have it growing at present in a dry location with mediocre soil, and it receives sporadic watering. It is next to beehive ginger that gets the same treatment, and they both keep on growing.

It is true that we could likely more than double the production from this plant if we were more proactive, and this is the intention moving forward.

The Queensland arrowroot plant that we have has now earned its keep in our system, so we will relocate some of the rhizomes to locations that will be more suited to giving bumper crops of rhizomes.

Growing this plant is just the start of the process. What to do with it once it has been harvested is the next challenge, and we address this here.

To see how we make arrowroot powder with our home grown rhizomes, “how to make arrowroot powder(with canna edulis)” is recommended. Once you have that down pat, this article titled “how to use arrowroot powder in the kitchen” is the next we suggest.

Is arrowroot an annual or perennial plant?

Arrowroot is a perennial plant with a growth habit of annual dieback similar to the common ginger and turmeric. This happens soon after the flowers have finished. This is when the leaves become a natural mulch layer for the rhizomes during the dry season.

How do you care for arrowroot?

To get the most from your arrowroot plant and give it the best care so you can obtain a good harvest, plant the canna edulis in a location that has at least half of the day in full sun, and have the soil well mulched.

Choose a spot out of the strongest winds, and water the plant occasionally. Too much water with poorly draining soil will rot the rhizomes.

How long does it take to grow?

Queensland arrowroot is a plant that will take up to 10 months to reach maturity and grow a good quantity of rhizomes. You can take from the roots after about the 6th month, but the best harvest is after the plant has died back.

How long does arrowroot take to sprout?

Once the warm weather has begun, the rhizomes will start to shoot. This is late October here in tropical Queensland. By late December, the plants should be waist-high and ready for the coming wet season.

arrowroot sprout
Freshly sprouted rhizomes ready for replanting.

If you are in cooler climates, the sprouting can be monitored by having the rhizomes on a bench in the shade or indoors. When the temperatures are optimal, the shoots will appear.

When do you harvest arrowroot?

Arrowroot rhizomes can be harvested when the top of the plant has collapsed and withered. This happens at the end of the growing season and is an annual event for this plant. This is the best time to take a fork and lift the rhizomes.

The rhizomes will keep in the soil if you don’t get to it straight away, and they can even be left in the ground to regrow the following year. The ground can get crowded with rhizomes after a few seasons, so we recommend lifting them at least once every two years.

We will be harvesting annually from now onwards and expanding the plantings and the harvests.

Does arrowroot grow back?

If left in the ground after the leaves have died back, the rhizomes in the soil will grow once the conditions that set the rhizomes to reshoot are in place. These are humidity and temperature related.

Are all parts of arrowroot edible?

All parts of the canna edulis plant are edible, but the plant is known for the starch that is in the rhizomes.

We have a dedicated article that explains what parts are edible and how to use them. The article is titled “What parts of the canna edulis plant are edible?” and we recommend it to you if you are looking at this plant as a potential grower in your yard.

It is a very useful plant and fits the type of multi-purpose variety that self-sufficient home growers should consider.

Where can I grow arrowroot?

Queensland arrowroot can be grown in many different locations, from the tropics to climates that get light frosts. It has been known to survive light snow. The plant will tolerate hot temperatures if the humidity is high, but hot, dry conditions will cause stress.

The colder the climate, the longer it will take to grow a crop, so in frost areas, expect a harvest every two years.

How tall does arrowroot grow?

Canna edulis can get to ten feet(+3mtrs) tall, and the height appears to be unaffected by soil conditions. There are opportunities presented with this height that can be useful in a yard design if you think about it.

It can make a great screen plant to shelter something like a softer plant or a chicken pen wall. Many of the taller gingers can be used the same way, but they are not as useful as the Qld arrowroot from an eating perspective.

All parts of the canna edulis are edible, whereas only some parts of the larger ornamental gingers are. If you are looking for a tall plant with lush green growth and lovely flowers later in the growing season, maybe the arrowroot is the winner.

Can arrowroot be grown in pots?

It can be grown in a pot, but the plant’s height is a challenge in the wind. We recommend you grow it in the ground where possible and if a pot is the only choice, use a large one with enough mass to provide stability. The pot would need to be pretty large to accommodate the spreading rhizomes.

What conditions does arrowroot grow in?

The best growing conditions for arrowroot are fertile soils that have plenty of organic matter dug into the soil. The pH of the soil is not a concern as the canna edulis will grow in a large range of soil pH types.

The soil can be sandy through to loamy mixes, and arrowroot will even grow in heavy clays, but rhizome rot can be an issue in clay.

canna edulis plants
Next seasons harvest underway.

The optimum soil is free draining with the ability to retain some moisture, with a good layer of mulch that can slowly feed the plant as it breaks down during the season.

How much water does arrowroot need?

Arrowroot will benefit from regular watering without needing to be nursed. It is a robust plant that will survive if it is forgotten for a few weeks at a time, but having said that, the more regular the watering, the better the rhizome harvest will be.

The canna edulis is a relative of the gingers, and the growth habits are pretty similar, but there are a few things that the canna prefers that the gingers will struggle with.

Arrowroot rhizome harvest
These grew without watering.

The watering needs of the gingers are more demanding, and the soil types are more specific vs. the canna edulis being able to take neglect and not being concerned about the soil type.

We have grown the arrowroot in a spot that has had no watering at all by us over a complete growing season, and while it did not give any rhizomes to speak of, the plant continued to grow. We are confident that if we had given some love to the plant, it would have loved us back a bit.

Does arrowroot need fertilizer?

You don’t need to fertilize the canna edulis plant if you don’t want to use chemical-based fertilizers. However, the arrowroot will respond to organic composts and good quality mulches, similar to the gingers.

Aged animal manures will also be beneficial to the outcome of your harvest.

When we relocate the next few arrowroot plants in our yard, we will be using organic soil that we take from the chicken pen as described in this article titled “making soil for raised garden beds“.

Can arrowroot grow in shade?

Queensland arrowroot does not like shade; the further away from the tropical areas, the more sun you will need to grow this plant successfully.

As mentioned above, we are in a tropical area and our canna edulis plants are in total sun and growing fine. They seem to love the light, so do yourself a favor and keep yours out of the shade.

Can arrowroot grow in cold climates?

Arrowroot will grow in colder climates reasonably well, although the time needed to obtain a reasonable crop is longer than the warmer climates.

The rhizomes are able to survive light frosts but to be sure of this, cover them with a thick layer of mulch to keep the soil temperatures more stable around the roots.

The rhizomes can also be lifted from the soil during the coldest periods, just as you would a ginger rhizome, and stored indoors out of the worst of the cold.

Can arrowroot grow with ginger plants?

They can grow together well, and the arrowroot can act as a shading element for the ginger. They both have similar season habits of growing when warm and being dormant in the cold.

The main issue you may run into is the soil pH, and we say this because the arrowroot is pH insensitive, whereas the gingers prefer a pH of 5.5-6.5. Have the soil pH aligned for ginger; they will be fine together.

The watering requirements of both plants match up, as do the mulch benefits. The soil type should lean towards the gingers’ preferences, which can be found in this article titled “what is the best soil for growing ginger?“. For information on mulch, “growing lots of ginger” is recommended.

Conclusions.

This site is about sharing what we know about the exact plants we depend upon each year, and if we are self-sufficient in that plant, we will let you know. Hopefully, this shows that it is possible to become self-sufficient in that particular plant if you wish.

Article by Tim Blanch for TheTropicalHomestead.com. He is a qualified Permaculture designer.