Yacon

Sun

Full sun; light afternoon shade can help in very hot climates.

Water

Water deeply during dry weather to keep the soil evenly moist, especially while roots are swelling; avoid waterlogged ground.

Soil

Deep, loose, fertile soil with good drainage; heavy or compacted soil makes harvesting difficult and encourages root damage.

Height

4-7 ft (1.2-2.1 m)

Spread

3-4 ft (0.9-1.2 m)

Flowers

Small yellow, sunflower-like flowers in late summer or autumn; flowering may be sparse or absent in short growing seasons.

Foliage

Large, soft, green, broadly triangular to heart-shaped leaves on thick, branching stems; frost kills the top growth.

Growth

Fast in warm weather.

Care needed

Medium

• Pollinators
• Edible

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Needs looking after

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   3 ft (0.99 m)

3. After 2 years

   5 ft (1.7 m)

   full size

About 2 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Growth rate

Fast

• Plant after the last frost, allowing about 3 ft (0.9 m) between plants.
• Mix compost into the soil before planting; avoid excessive nitrogen, which encourages leafy growth.
• Water regularly through dry spells rather than letting the plant repeatedly wilt.
• Mulch once the soil warms to conserve moisture and suppress weeds.
• Stake plants in exposed gardens before the stems become top-heavy.
• In frosty regions, lift planting crowns before the ground freezes and store them frost-free.

Pruning. No routine pruning is needed during growth. Cut stems back after frost blackens the foliage, leaving short stubs to help handle the crown during lifting.

Lift the swollen storage roots in late autumn, usually after at least six months of growth, when the foliage yellows or the first light frost blackens it; harvest before the soil freezes. Loosen the soil widely with a fork and lift carefully, as the roots snap easily, keeping the small bud-bearing crown pieces separate for replanting. A few days in a warm, frost-free place can sweeten the edible roots;

Late winter

Check stored crowns and discard any that are soft or rotten; pot up sound, bud-bearing pieces under frost-free cover.

Spring

Prepare a sunny bed with compost and gradually acclimatise young plants to outdoor conditions.

Late spring

Plant out after frost danger has passed and the soil has warmed.

Summer

Water during dry spells, maintain mulch and stake plants where wind is a problem.

Autumn

Let plants continue growing while conditions remain mild so the storage roots can swell.

Late autumn

Harvest roots and save the planting crowns; in frost-free gardens, divide crowded clumps after top growth dies back.

Winter

Keep saved crowns cool and frost-free in barely moist compost, checking occasionally for rot or shrivelling.

• Plant at the back of a vegetable bed so its height does not shade shorter crops.
• Use broad leaves as a seasonal contrast beside fine-leaved culinary herbs.
• Grow in an edible border with flowers that remain visible around its base.
• Use a row as a temporary summer screen, allowing access for autumn lifting.

Garden styles it suits: Potager (kitchen garden), Edible landscape, Homestead, Cottage garden, Modern tropical and Food forest.

Plant it with: Nasturtiums, Calendula, French marigolds and Chives.

Wildlife: Flowers can attract bees and other insects when produced, but flowering is unreliable in cool or short-season gardens.

• Slugs and snails damage emerging shoots: protect young growth with barriers, night-time collection or locally approved slug controls.
• Wind can snap tall stems or loosen crowns: choose a sheltered site and stake early.
• Waterlogged soil causes crown and root rot: improve drainage or grow in raised beds, and keep stored crowns only barely moist.
• A short growing season gives small crops: start crowns under cover and plant out promptly once frost danger has passed.

The storage roots are edible for people and are not known to be toxic; large servings can cause wind, bloating or diarrhoea because they contain poorly digested fructans. Yacon is not known to be toxic to cats, dogs or horses, but species-specific safety information is limited. Do not assume leaves, stems or planting crowns are suitable animal feed.

• Jerusalem artichoke (Helianthus tuberosus)

  Jerusalem artichoke usually has narrower, rougher leaves and knobbly stem tubers; yacon has broader leaves and elongated, smooth-skinned storage roots.

• Mexican sunflower (Tithonia diversifolia)

  Mexican sunflower has conspicuously lobed leaves and much larger yellow flower heads; yacon leaves are usually unlobed and its flowers are small.

Yacon comes from the Quechua name for the plant, while sonchifolius means sow-thistle-leaved.

Propagation. Divide the compact crown into pieces with at least one healthy bud in late winter or spring, then pot them up frost-free. The large edible storage roots generally lack buds and will not produce new plants on their own; seed is uncommon and unreliable.

Accepted botanical name

Smallanthus sonchifolius

Native range

Bolivia, Colombia, Ecuador and Peru.

Sources: GBIF (CC BY 4.0) and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.