Helianthis, a root vegetable with beautiful flowers

Helianthis - Helianthus strumosus

Helianthis advantages: cute flower, delicious tuber, disease resistance, low water needs.

Helianthis key facts

Name: Helianthus strumosus
Common: pale-leaved woodland sunflower, helianthis
Family: Asteraceae
Type: Root vegetable

Height – 3 to 6 ½ feet (1 to 2 meters)
Planting distance – every 20 to 24 inches (50-60 cm)
Exposure – full sun
Soil – any type

Planting: mid- to late spring     –    Harvest: end of winter, beginning of spring

Perfect substitute for potato in any recipe. And, not to be forgotten, helianthis is also a very beautiful perennial with bright yellow flowers, like its cousin Jerusalem artichoke.

Planting Helianthis

Two options to get your helianthis crop going: start from sowing seeds or plant nursery seedlings.


Planting and sowing helianthisTo sow helianthis seeds, first loosen up the soil and amend it with extra soil mix, compost or manure.

Remove any weeds (self-sown plants that you don’t want growing there) and then sow the seeds by burying 2 or 3 of them about half-an-inch deep (1 cm).

After 10 to 15 days, you should see sprouts appear. From each cluster, keep only one seedling, the most vigorous one. This is called thinning.


Ornamental helianthisPrepare soil just as you would for sowing: loosen it up and clear weeds out. Plant the tubers around 5 inches deep (10-15 cm). Alternatively, you can just lay them on the ground and cover them with soil, forming a ridge that’s also 5 cm deep.

When planting in a vegetable patch, space each plant by nearly 2 feet (50 to 60 cm) along a row.

When growing the plant in an ornamental flower bed, try to keep the planting density at around 4 or 5 helianthis stems per square yard or meter.

Growing and care for helianthis

Caring for helianthisUnlike potato, which requires constant care (watering, mildew control, ridging…), your Helianthis won’t need any care at all!

This very hardy plant is easy to care for and it doesn’t need much water. However, stay watchful in case of long-lasting drought.

Note that if your plants are in a spot where it gets windy, the tall, gangly stalks risk breaking and falling over:

  • you might have to consider staking them.
  • An alternative to staking in this case it ridging, bringing soil up around the stems by 6 inches (15 cm). This strengthens their base.

Harvesting Helianthis

You can harvest your helianthis tubers at the end of winter (end of February, early March).

The easiest way to do this is to lift soil up with a pitchfork. Start out at a distance, working from the outside towards the stem: this will let you lift tubers out without bruising them.

Keeping Helianthis

Helianthis keeping storageWhen dug out and exposed to open air, Helianthis tubers quickly lose their water and wilt away rather fast.

They won’t keep for very long, unlike Peruvian oca or potato.

It’s thus best to only unearth tubers the week you plan to eat them.

Good to know: the fresher they are, the more digestible they’ll be to eat.

Diseases and pests

Helianthis diseases and pestsAs is often the case in vegetable patches, your main enemies are slugs and snails. They will keep your stems from blooming by repeatedly attacking stems and leaves.

Note that some small black slugs, Arion hortensis, may even cause damage to the tubers.

As for diseases, Helianthis is highly resistant to powdery mildew.

Smart tip

Since you harvest helianthis tubers in the same season you plant them, simply set a few roots aside to plant again immediately when harvesting.

Images: Pixabay: Hans Benn, Public Domain: Mike Linksvayer, Nathan Rauh, Joseph McPhail, shutterstock: COULANGES