Start from seed: August-September (using tubers)
Optimum soil temperature for germination: 8-15°C
Plant spacing: 30-40 cm
Days to maturity: 140-150 days
Introduction
Jerusalem artichoke (Helianthus tuberosus) is a perennial belonging to the Compositae family, which also includes sunflowers, lettuces, and globe artichokes. Despite its name, it is not related to true artichokes nor does it have any connection to Jerusalem. They are often referred to as Sunchokes.
The Jerusalem artichoke is native to North America where it was cultivated by indigenous peoples long before European contact. Archaeological evidence suggests it was domesticated as early as 3000 BCE in the eastern regions of North America. Following European contact in the 17th century, it was brought to Europe where it became a popular crop, particularly in France and other European countries.
The plant grows as a tall, sunflower-like perennial reaching heights of 2-3 meters, with bright yellow flowers that appear in late summer. Below ground, it produces clusters of edible, knobbly tubers which have a nutty, slightly sweet flavour often compared to water chestnuts or artichoke hearts. They are particularly valued for their inulin content, a type of carbohydrate that doesn’t raise blood sugar levels, making them suitable for diabetic diets.
Inulin is undigestible by humans and is the reason artichokes cause flatulence, and in some people serious indigestion. It is advisable to try them in small quantities if you are unfamiliar with them. This effect can be reduced by cooking then with something acidic, such as lemon juice, which converts some of the indigestible starches to digestible sugars, or to cook them twice, for example, boil them then roast them.
Site and soil
Jerusalem artichokes can be successfully grown in Canberra, as they are adaptable to a wide range of conditions. They prefer full sun but will tolerate partial shade, though this may reduce tuber production. Being tall plants, they should be planted in an area protected from strong winds to prevent stems from being damaged when laden with flowers. When selecting a spot, be mindful of the shade created by such tall plants.
The main consideration is that they propagate very easily from both whole and parts of tubers. They will rapidly cover entire patches and become a weed so be careful about where you plant them. Once established, they are very hard to eliminate.
Prior to planting, prepare the soil by incorporating compost or aged-rotted manure. They prefer fertile, well-drained soil with a pH between 6.0-7.5. Sandy loams or loose soils work particularly well, as they make harvesting the tubers easier. Jerusalem artichokes are not particularly fussy about soil, but improved soil structure will result in better-shaped tubers that are easier to clean.
For container growing, use large pots at least 45-50 cm deep and wide. Fill with premium potting mix boosted with compost and a complete organic fertilizer. Container growing will avoid the plant spreading.
For details on preparing soil and pots, including the use of lime, dolomite, gypsum and fertilizers, please refer to the COGS guide to garden bed preparation.
Planting Seeds and Seedlings
In Canberra, Jerusalem artichokes are best planted in late winter to early spring (August-September). Unlike most vegetables, they are propagated from tubers rather than seeds.
Select firm, disease-free tubers for planting. Each tuber can be planted whole or cut into sections ensuring each piece has at least two or three “eyes” or growth buds. Allow cut surfaces to dry for a day before planting to reduce the risk of rot.
Plant tubers approximately 10 cm deep and space them 30-40 cm apart in rows that are 50cm or so apart. After planting, water well and apply a layer of organic mulch to suppress weeds and retain soil moisture.
Jerusalem artichokes grow quickly once conditions warm up, and young shoots may need protection from late frosts. The plants require minimal care once established and will typically reach their full height by mid-summer.
Cultivation
Jerusalem artichokes require around 140 frost-free days to produce a good crop of tubers. Young plants are susceptible to frost damage, so protection may be necessary for early plantings. Once established the plants are quite hardy.
Water regularly, especially during dry periods, to ensure consistent soil moisture. While Jerusalem artichokes are relatively drought-tolerant compared to many vegetables, adequate water during tuber formation will result in larger, better-formed tubers.
Jerusalem artichokes need a good supply of potassium for tuber development. This can be supplied with wood ash or a complete organic fertiliser applied at planting. Avoid high-nitrogen fertilisers, which promote excessive leaf growth at the expense of tuber production.
The tall stems may require staking in exposed sites to prevent wind damage. In very windy locations, you might consider pinching out the growing tips when plants reach about 1 meter to encourage a more branched, bushier habit that is less likely to blow over.
Tuber development begins as days shorten in late summer, with most growth occurring in autumn as the above-ground portions of the plant begin to die back.
Harvesting
Jerusalem artichokes are typically ready to harvest from late autumn through winter, approximately 140-150 days after planting. In Canberra, this usually means from May onwards. Tubers can be left in the ground and dug as needed throughout winter, as they store best in the soil.
Harvest by carefully digging around the base of the stems with a garden fork, being careful not to damage the tubers, which can bruise easily due to their thin skins. The entire plant can be lifted to harvest all tubers at once, or you can selectively harvest larger tubers and leave smaller ones to grow. The flowers can be harvested for cut flowers.
If you intend to grow Jerusalem artichokes again the following season, there’s no need to replant – any small tubers left in the soil will regrow.
Harvested tubers don’t store as well as potatoes. They can be kept refrigerated in a container or perforated plastic bag for 2-3 weeks. For longer storage, they can be left in the ground and harvested as needed, or stored in damp sand in a cool, dark place.
Problems
The best approach is to have a reliable Australian reference book to identify problems. Garden Pests, Disease and Good Bugs by Denis Crawford is recommended.
A general strategy to follow with any problem is to observe the plant carefully before taking action. Identify the problem then carefully consider the course of action. For example, with pest insects, you often can see a predator nearby. If you watch and wait the predator may deal with the problem for you. Beneficial predatory insects which feed on pest insects can be purchased from suppliers such as Bugs for Bugs. If the problem needs further action the above recommended book has suggestions.
Practicing good garden hygiene, crop rotation, and maintaining plant vigour by providing adequate nutrients are key strategies for prevention.
Jerusalem artichokes are generally resistant to pests and diseases in Canberra gardens, but they can face several challenges:
Slugs and Snails: These pests can damage young shoots and create holes in tubers. Control methods include beer traps, copper barriers, organic slug baits, or evening patrols to manually remove them.
Two-spotted Mites: More common in hot, dry conditions, these tiny pests can cause stippling on leaves. Increase humidity around plants by regular misting and apply horticultural oil if infestation is severe.
Powdery Mildew: A fungal disease that can appear as white powder on leaves in humid conditions with poor air circulation. Ensure adequate spacing between plants and avoid overhead watering.
Sclerotinia Rot: This fungal disease causes rotting at the base of stems and whitish mould. Practice crop rotation and remove affected plants promptly to prevent spread.
Spreading Habit: Perhaps the biggest problem with Jerusalem artichokes is their tendency to spread. They can become invasive if not contained, as even small pieces of tuber left in the soil will regrow. Consider planting in contained beds or large pots if this is a concern.
Recommended Varieties
Perhaps the easiest way to start growing Jerusalem artichokes is to ask for a few tubers from someone you know growing them or plant a few that you have purhcased. Several Jerusalem artichoke varieties perform well in Canberra’s climate:
White Fuseau: A popular variety with smoother, less knobbly tubers that are easier to clean and peel. Produces good yields of elongated white tubers and grows to about 2-2.5 meters tall.
Red Fuseau: Similar to White Fuseau but with reddish-purple skin. The tubers are long, smooth, and often spindle-shaped, making them easier to prepare than knobby types. It’s considered particularly hardy.
Mammoth: Also known as French White Mammoth or White Mammoth, this variety produces large tubers with white flesh. Plants can grow up to 3 meters tall and are very productive.
Stampede: An early-maturing variety (around 90 days) that produces large tubers, often weighing up to 200 grams each. Good for areas with shorter growing seasons.
References
- Bubel, Nancy. The New Seed-Starters Handbook. Rodale Books, 2018.
- Crawford D. Garden Pests, Disease and Good Bugs. Australia: ABC Books; 2015.
- Department of Primary Industries and Regional Development. (2024). Growing Jerusalem artichokes in Western Australia. Agriculture and Food. https://www.agric.wa.gov.au/artichoke/growing-jerusalem-artichokes-western-australia
- Dove, Helena. Botany of the Kitchen Garden, Kew Publishing, Royal Botanic Gardens Kew, UK, 2023.
- Green Harvest. (2024). Jerusalem Artichoke Growing Information. https://greenharvest.com.au/Plants/Information/JerusalemArtichoke.html
- The Seed Collection. (2024). How to Grow Jerusalem Artichoke. https://www.theseedcollection.com.au/growguide/jerusalem-artichoke
