How to Plant, Grow, and Care for Arrowroot

Arrowroot is becoming well known as a gluten-free alternative to corn starch and flour. What isn’t advertised on the nutritional label, though, is the rich history of arrowroot powder and the species it comes from. It was cultivated in Latin America as early as 8200 BCE, thousands of years before gluten was even identified. Back then, it was well known for extracting poison from arrow wounds, hence the name arrowroot plant.

The common name ‘Arrowroot’ is actually applied to multiple species, mostly those whose roots can be made into arrow starch or flour. The more commonly known ones are Canna indica, which is grown for its elegant flowers, and Zamia pumila, known as Florida arrowroot. In this article, we’ll focus on the arrowroot that’s primarily used for commercial arrowroot flour and starch: Maranta arundinacea.

M. arundinacea is a large, tropical species that grows in water margins. Its lively green foliage is as much at home near a backyard pond as it is in a rainforest. You’ll find that it’s very easy to grow in warm climates (and even easier to propagate). So if your water feature – or a soggy part of the yard – could use some sprucing up, consider the arrowroot!

What is Arrowroot?

Our arrowroot is in the Marantaceae family, making it cousins with the popular houseplant M. leuconuera (prayer plant). Since they’re both popular, Marantaceae may be referred to as either the arrowroot family or the prayer plant family. M. arundinacea itself was previously called Maranta sylvatica. It also goes by the common names West Indian arrowroot and obedience plant (not to be confused with the sprightly ‘obedient plant’).

Native Area

As mentioned earlier, arrowroot is native to Latin America, from Mexico to the West Indies to Brazil. It thrives in warm, humid environments where it grows in forested areas and along riverbanks.

Characteristics

True to its tropical habitat, it has smooth, ovate leaves that are at least six inches long. It grows in clusters that can reach five feet tall and blossoms in the spring and summer with a subtle display of tubular white flowers.

Arrowroot produces rhizomes, which are ground into powder. They’re white or reddish-purple and sprout thick green stems. They’re a good source of potassium and have a nutty, sweet flavor when eaten raw or cooked. The rhizomes are very digestible and sometimes fed to infants.

As an arrowroot rhizome ages, it gets woody, fibrous, and more difficult to eat. In mild winters, it goes dormant, and the foliage often dies back. Come spring, the rhizomes will sprout new stems and leaves.

Your everyday arrowroot has solid green leaves. If you’re looking for something fancier though, search for a ‘Variegata’ cultivar. Its leaves are painted with chunks of white and light green.

Planting

Arrowroot starts and seeds may be found at gardening centers, depending on where you live. You can also search for and order them online. If you’re planting by seed, sow them in sprouting pots or directly in the ground. Soak the seeds first to increase the germination rate. 

Grow your starts in the spring. This will give them plenty of time to establish a root system and shoot up before going dormant in the winter. Ideally, arrowroots should be planted in a water margin. It needs a lot of moisture, so placing it somewhere wet will save you a lot of time spent watering. The location you choose should also get partial shade for most of the day.

Arrowroot can grow in containers as long as they’re pruned or divided periodically (these are big!). Choose a sturdy container with good drainage holes. While it’s possible to grow arrowroot indoors, it does much better outside. 

How to Grow

Arrowroot is an agreeable perennial. As long as it was planted in the right conditions and the following needs are met, you shouldn’t have any issue growing a plentiful harvest.

Light

Arrowroots are best cultivated in partial shade with direct sunlight limited to a couple of hours a day. However, they’ve been reported to survive in a warm sunny position as well as full shade, albeit with less vigorous growth. 

Water

Remember that arrowroot grows in water margins, so naturally, it needs plenty of moisture. Keep the soil constantly moist, watering daily if needed. Arrowroot also prefers some humidity, which is easily accomplished if it’s planted next to a pond.

If your arrowroot gets hot and dry, its leaves will let you know. To increase the humidity, mist the air around it with a spray bottle. Avoid getting large amounts of water on the leaves, as this can lead to fungal growth.

In the winter, when your M. arundinacea goes dormant, cut down to weekly watering. Not only does it need less water, but too much will make the roots cold. When new growth emerges in the spring, gradually increase watering. 

Soil

All that water is useless if we don’t have good soil to hold it. Choose a loamy, well-drained soil that will stay moist without becoming muddy. It should drain well enough that large puddles aren’t left on the surface, and excess moisture drains out the bottom of a container.

Use soil that’s rich in nutrients and organic matter. It should also be slightly acidic, with a pH of 5.5-6.5. Though all these soil characteristics are important for growing arrowroot, the plant will usually survive in varying soil qualities if needed.

Temperature

Because it’s native to the tropics, growing arrowroot is easiest in zones 10-12. It thrives in temperatures from 62-93°F (17-34°C) during the growing season. Arrowroot may survive temperatures as low as 40°F (4°C) and even some light frost during the dormant season. Adding some mulch in the fall may help the crop stay warm through the winter months.

Fertilizing

Fertilize your arrowroot in the spring for a jump start on healthy growth. Use a diluted, balanced, liquid fertilizer one to two times a month for the season (seaweed tonic is a popular choice for this crop). It can be overfertilized – especially in the summer – and will show it with leaf discoloration. 

Maintenance

You’re likely to reach for the garden shears at harvest time but not during the rest of the growing season. You can prune spent flowers or unsightly leaves as needed. If your arrowroot is going to overwinter in cold temperatures, cut down the above-ground growth in late fall.

Propagation

Since they spread through rhizomes, arrowroots are easy to propagate through division. Container specimens may need to be divided as they outgrow their pots. You can also divide it during harvest since the roots will already be exposed.

To divide container arrowroots, lift them out of their pot and gently shake off the soil. Then, carefully separate individual tubers from the clump. Each piece you separate must have roots and a shoot. You may need to cut the rhizomes apart with a clean knife. For arrowroot growing underground, first dig up a portion of the roots and then slice them apart with a spade.

Arrowroot can also be propagated by cuttings for a less invasive option. In late spring or summer, clip off a healthy stem at the base. Set the cutting upright in some well-draining soil and keep it moist. In about a month, the cutting should start developing its own root system.

Harvesting

After at least a year of growth, your arrowroot should have some tasty roots ready to harvest. Here’s how to get started.

Edible arrowroot tubers should be harvested when they’re young. They should be about six inches long and white. Older, woody roots aren’t useless, though – they’re a valuable addition to mulch or compost. They can also be replanted and sprouted.

To harvest, you’ll need to dig up the roots and cut them free from the stems and leaves. If you want to keep it growing afterward, leave a section untouched and replant it. You can use this opportunity to divide or prune the roots if needed.

Storage

Cooking and eating arrowroot is similar to how you would with potatoes. Eat them in soups, casseroles, or as a side dish. Any leftover, uncooked roots can be stored for about a week in the fridge. You may be able to extend the fresh shelf life of chopped roots by keeping them in a container of water in the fridge (change the water periodically). 

Common Problems

Since this is low-maintenance, it’s safe to assume that Maranta arundinacea doesn’t come with many problems. However, hungry pests and unexpected growing conditions are always possible, so we’ll review the possibilities here.

Growing Problems

Arrowroots love their humidity, so direct sunlight and high heat should be avoided. If not, the foliage will dry out and curl on the ends. You can remedy this by misting the foliage with water and ensuring the soil is holding its moisture well. If this is a recurring problem, transplant your arrowroot into a location that gets more shade in the afternoon. Damage to the leaves may not be reversible, so scorched leaves should be pruned off.

For many varieties, yellowing leaves are the default way of signaling that something’s wrong. If your arrowroot is losing its lovely green pigment, it could be getting too much sunlight, water, or fertilizer. A pest or disease may be at fault if none of these seems to be the problem.

Pests

Scale insects are gross. They also spread quickly, so don’t hesitate to remove them from your garden. These multitudes of insects are oval and range in color from brown to white. They’ll feed on arrowroot sap and drain it of essential vitamins and nutrients. This may stunt the growth, turn the leaves yellow, and even cause foliage loss.

Prevent pest infestations by ensuring good airflow between the leaves of your arrowroot. You should also keep the soil clear of debris. Large-scale infestations can be cleared with horticultural oil spray or insecticidal soap.

Spider mites are another unpleasant possibility when growing arrowroot. These mites spin ultra-fine webs across their host, making them relatively easy to identify. They cause damage similar to scale insects and may also cause stippling across the foliage.

Unlike scales, spider mites thrive in dry environments. If you provide sufficient humidity for your arrowroot, you’ll likely prevent infestations (just don’t go too far, or you’ll invite the scales!). The insecticidal controls for scale also work for spider mites. You may also use beneficial insect predators, such as predatory mites, ladybugs, or lacewings.

Diseases

Rust fungus shows up as reddish-brown spores on a leaf. It’s unlikely to kill your arrowroot, but it can hurt its growth (and aesthetic value). If you notice rust fungus on your arrowroot, immediately remove and destroy any infected leaves.

Humid conditions are ideal for rust fungus, which explains why it’s common with M. arundinacea. Counter the humidity by ensuring that there’s good airflow between the leaves (you may need to prune them). 

Frequently Asked Questions