Smallanthus spp.

yacon

Asteraceae

Americas, from the eastern United States and Mexico to the Andes

Attracts Pollinators Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterMedium

HardinessZones 7–10

Overview

Smallanthus spp. is a genus of robust perennial herbs in the daisy family, with about 21 species native to the Americas. Plants grow from thick, tuberous roots and produce stout, often hollow stems 3-8 feet (0.9-2.4 m) tall. Leaves are large, opposite, broadly triangular to arrow-shaped, 6-12 inches (15-30 cm) long, with winged stalks and toothed or lobed margins. Daisy-like flower heads 0.6-1.6 inches (1.5-4 cm) across carry short yellow to orange ray florets around a yellow disc, borne in branched clusters in late summer and fall. The cultivated yacon (Smallanthus sonchifolius) is grown for its sweet, crisp storage roots, which can weigh several pounds each. Fibrous offset tubers at the crown produce the next season's shoots. Top growth dies back after frost, and the roots overwinter where the ground does not freeze hard. Plants need a long, frost-free season to develop a full root crop.

Native Range

Smallanthus spp. species are native to the Americas, from the eastern United States and Mexico through Central America to the Andes of South America. They grow in moist meadows, forest edges, stream banks, and disturbed ground. Yacon (S. sonchifolius) is a long-cultivated crop of the Andean highlands and is not known in the wild.

Suggested Uses

Yacon (S. sonchifolius) is grown in vegetable gardens and field plots for its edible storage roots, spaced 24-36 inches (60-90 cm) apart, and the tall wild species are used in large naturalistic and pollinator plantings. The large size and long season needed for a root crop leave yacon less suited to short-summer or small gardens. The flowers attract bees and other insects.

How to Identify

Recognized by tall, stout stems carrying large, opposite, triangular to arrow-shaped leaves 6-12 inches (15-30 cm) long on winged stalks, topped by clusters of small yellow to orange daisy-like heads 0.6-1.6 inches (1.5-4 cm) across. The cultivated yacon also shows a crown of fibrous offset tubers above the larger eating roots. The winged leaf stalks and paired leaves separate it from sunflowers (Helianthus spp.).

Appearance

Size & Dimensions

Height3' - 8'

Width/Spread2' - 4'

Reaches mature size in approximately 1 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Summer Fall

Flowering occurs in late summer and fall, mainly August through October, and may be cut short by early frost in cool climates. The clustered heads open over several weeks. In short-season areas, plants may be killed by frost before flowering, with the root crop forming regardless.

Detailed Descriptions

Flower Description

yellow to orange

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 6-10 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.5(Neutral)

357912

Soil Types

loam silt sand

Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

tender

Time to Maturity

6-7 months to root harvest

Care & Maintenance

Care Guide

Smallanthus spp. grows in full sun to part shade on deep, fertile, moist but well-drained soil, with steady water through the growing season. The cultivated yacon is grown much like dahlias, started from crown offsets once frost danger has passed and lifted before hard freezes. A long, frost-free season of about six to seven months produces the largest roots. Top growth is frost-tender, though the roots survive light frost in the ground. Few serious pests affect the genus. Drought during root formation reduces the harvest.

Pruning

No routine pruning is needed during growth. After frost blackens the foliage, stems are cut down, and the root clump is lifted for storage or division. The crown offsets are separated for replanting, while the larger storage roots are kept for eating.