Vegetable · Euphorbiaceae
Cassava
Manihot esculenta
A bold kitchen-garden shrub with a season-long rhythm and a serious safety story.
Full sun
Every 7–14 days
59–95°F · 15–35°C
240–360 days
Overview
Few edibles command a backyard quite like cassava. Standing 5 to 10 feet (1.5 to 3 m) tall and spreading 3 to 6 feet (90 to 180 cm), this woody tropical shrub reads more like an architectural backdrop than a row vegetable, giving the warm-season garden height, structure, and a relaxed tropical mood that holds the eye from spring planting through autumn harvest.
Grown for thousands of years and native to South America, cassava is a major staple crop across warm regions, prized for the starchy roots that fill out beneath the foliage. In the home garden it earns its keep as a low-fuss, drought-tolerant anchor that sets the pace of the season: plant as the weather warms, let it build quietly through the heat, and lift the roots when the tubers have bulked.
The catch is the one to remember. Every part of the plant, roots and leaves alike, carries cyanide-forming compounds, so cassava is only an edible after careful peeling, grating or soaking, and thorough cooking. Treated with that respect, it is a striking and generous presence; treated casually, it is genuinely dangerous, which makes safe handling part of the daily routine rather than an afterthought.
Care
The short version: give cassava full sun, a well-drained sandy loam, and a long frost-free season. Water young plants to settle them in, then ease off, since it is highly drought-tolerant once established. Feed a balanced NPK with potassium at planting, plant from stem cuttings after frost, and harvest the roots 8 to 18 months later. Never eat any part raw.
Light
Give cassava a full-sun position where it can soak up the warmth all day, which suits both its growth and its place as a tall, light-loving backdrop in the garden. It will tolerate partial shade, though an open, sunny spot brings out its best form and the strongest root development below.
Water
Settle young plants in with regular water, then step back, because cassava is highly drought-tolerant once established. In dry spells, water every 7 to 14 days and let the top 3cm dry between drinks. Steer well clear of waterlogged soil, which invites root rot and quietly diminishes the quality of the harvest.
Soil
A well-drained sandy loam is the foundation of a good crop, keeping the roots out of standing moisture as the tubers form. Aim for a pH of 5.5 to 6.5, and on heavier or wetter ground, plant on ridges so the soil drains freely through the long growing season.
Temperature
This is a warm-climate plant at heart, happiest between 59°F to 95°F (15°C to 35°C). It is frost-tender, and even a brush with freezing temperatures will blacken the foliage, so reserve it for genuinely frost-free seasons or the warmest zones where the heat holds.
Humidity
Average humidity of 40% to 70% suits cassava well, and it copes comfortably with drier air, which makes it an easygoing fit for many garden settings. There is no need to fuss over moisture in the air; ambient conditions are usually plenty.
Feeding
Keep feeding simple and front-loaded: a balanced NPK with adequate potassium for root development, applied at planting only. The potassium matters most here, since it supports the starchy roots that are the whole point of the crop.
Pruning
Cassava asks for very little pruning. Remove the lower lateral shoots to focus the plant's energy, and cut back any stems lost to damage or frost. At the close of the season, set aside the healthy stems as cuttings for next year's planting.
Repotting
not typically container-grown
Size & spacing
Plan for presence: cassava reaches 5 to 10 feet (1.5 to 3 m) tall and spreads 3 to 6 feet (90 to 180 cm), so it earns a standalone spot rather than a tidy vegetable row. Grown outdoors only and not suited to containers, it works beautifully as a seasonal anchor at the back of a bed.
When to plant
Cassava keeps a clear seasonal rhythm in the garden. Stakes go in once the danger of frost has passed and the soil has warmed, the shrub fills out through the heat of the year, and the roots are lifted 8 to 18 months after planting, once the tubers have bulked and before the first frost brings the season to a close.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Plant woody stem cuttings (stakes) after all danger of frost has passed and soil is warm.
- Harvest: Harvest roots 8-18 months after planting, once tubers have bulked.
Hardiness
USDA hardiness zones: 9–11
Temperature: down to -7°C
Troubleshooting
For all its easy presence, cassava has a short list of troubles worth watching for through the season. A virus carried on planting stock, soggy ground that spoils the roots below, and the cold that ends everything overnight are the issues most likely to interrupt a clean harvest.
Mosaic virus arrives with the planting stock
When the canopy turns patchy and the shrub stalls out, cassava mosaic virus is usually the culprit, carried in on whiteflies or on cuttings that were already infected before they went into the ground. There is no cure, so the kindest thing you can do for the rest of the garden is to pull and destroy the affected plants and begin again with certified virus-free stakes.
Fix:
- Remove and destroy infected plants
- Use virus-free planting material
- Control whitefly vectors
One cold night ends the season
Cassava is frost-tender, and a single night near or below freezing will blacken the foliage and stems and bring the whole plant down. In all but the warmest zones, treat it as a single warm-season crop: time the planting and the harvest to the frost-free window, and get the roots out of the ground before the first hard cold arrives.
Fix:
- Harvest roots before frost
- Protect or relocate if possible
Wet feet spoil the harvest below ground
A shrub that wilts above ground while its tubers turn soft, discolored, and foul-smelling is telling you the soil has stayed too wet for too long. Set the next planting on ridges or a freely draining site, ease off the watering can, and lift the roots promptly once they have bulked so a good season does not end in waste.
Fix:
- Improve drainage
- Avoid overwatering
- Harvest promptly once mature
Toxicity
This is the part of growing cassava that calls for genuine caution. All parts of the plant contain cyanogenic glycosides that release hydrogen cyanide when the tissue is damaged, which makes the raw or improperly processed plant truly poisonous to people and animals alike. The facts below are not stylistic flourishes; they are the safety basics that keep a household and its pets out of harm's way.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Severe
In cats, raw cassava can release hydrogen cyanide, bringing on drooling, vomiting, labored breathing, and dilated pupils, followed by weakness, convulsions, and collapse. Keep raw roots and leaves entirely out of reach.
Dogs Severe
A dog that chews raw cassava may drool and vomit, then struggle to breathe, stagger, and slip into seizures as the cyanide takes hold. This is a medical emergency that warrants the vet without delay.
Horses Toxic
Horses that graze raw cassava can show fast, distressed breathing, trembling, and stumbling, and a large dose can be fatal. Fence the plant off from any pasture they reach.
Rabbits Toxic
Rabbits have small bodies that handle cyanide poorly, so even a little raw cassava can bring on weakness, gasping, and twitching. Never offer any part of the raw plant to them.
Livestock Severe
In cattle, goats, and sheep, raw cassava can trigger rapid breathing, drooling, and staggering, progressing to muscle tremors, convulsions, and collapse. Keep grazing animals well clear of the plants.
Birds Toxic
Poultry and pet birds can suffer labored breathing and sudden weakness from raw cassava, and their small size makes even a modest amount serious. Keep all raw plant material away from them.
People Caution
Cassava feeds millions, but only after it is peeled, grated or soaked, and cooked. Raw or half-processed roots and leaves release cyanide that causes vomiting and dizziness, and steady under-processing can lead to konzo paralysis. No part should ever be eaten raw.
Proper processing (peeling, grating/soaking, and thorough cooking) drives off the cyanide and renders cassava safe to eat; the raw plant and unprocessed roots/leaves are dangerous. Keep raw plant material away from children and animals.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Cassava comes in two broad camps, and the difference is about how much processing the kitchen demands rather than how the plant looks in the garden. Both still need peeling and cooking; neither is ever safe raw.
Sweet cassava
Carries fewer cyanide-forming compounds, most of them held in the peel, which makes for easier kitchen-garden cooking. It still must be peeled and cooked before it reaches the table.
Bitter cassava
Holds cyanide-forming compounds throughout the root, so it demands heavy processing: grating, soaking, fermenting, and cooking before it is safe to eat.
How to propagate
Bringing on the next year's crop is part of the pleasure of growing cassava. The plant propagates from its own woody stems rather than seed, so a healthy season hands you the material for the one that follows.
Stem cuttingsEasy
Plant mature woody stem cuttings (stakes) at the start of the warm season after frost danger has passed. · 2 to 4 weeks for sprouting and rooting
This plant is grown from woody stem cuttings called stakes, not from tubers or seed. Take pieces 20 to 30 cm long from mature, healthy stems, set them out as the warm season opens, and watch for fresh shoots and roots in about 2 to 4 weeks.
Myths
A quick boil makes any cassava safe to eat.
Bitter types call for peeling, grating, soaking, and a long cook; a brief boil leaves far too much cyanide behind. Under-processing the same roots over time can lead to cyanide poisoning and konzo paralysis.
Only the roots of cassava are poisonous.
The leaves carry the same cyanide-forming compounds as the roots. Both must be properly processed before any person or animal can safely eat them.