Sunchokes, or Jerusalem Artichokes (Helianthus tuberosus), are a perennial plant grown primarily for their edible tubers, which are a source of the prebiotic fiber inulin. As a member of the sunflower family, they feature tall, thick stalks crowned with small, yellow flowers in late summer. Their impressive and rapid vertical growth creates a striking presence in the garden, presenting both opportunities and challenges for the home gardener.
Typical Height Range
The most common varieties of sunchokes typically grow to a height between 6 and 10 feet. This stature makes them one of the tallest vegetable crops a gardener can cultivate, often towering over corn and other perennial plants. Height potential is linked to the plant’s ability to store carbohydrates in the stems before transferring them to the tubers, meaning taller growth indicates a higher yield potential.
While most plants remain within this range, certain heirloom varieties, coupled with optimal growing conditions, can achieve heights of 12 to 15 feet. Some plants have even been recorded reaching up to 16 feet, resembling small trees by the end of the season. The specific genetics of the chosen cultivar, such as the ‘Dwarf Sunray’ variety, will influence the final measurement, with some intentionally bred varieties staying shorter than the standard range.
Environmental Factors Affecting Stature
The ultimate height a sunchoke plant reaches is directly governed by the growing environment’s ability to support its vigorous nature. Maximizing vertical growth requires significant energy, which the plant primarily derives from uninterrupted sunlight exposure throughout the day. Plants placed in full sun will reach their genetic height potential, while those in partial shade will show visibly reduced stature.
Soil quality plays a substantial role in vertical development. A rich, well-draining, and loose soil structure encourages a robust root system capable of supporting a towering stalk. Although sunchokes are resilient and can tolerate poor or heavy clay soils, these conditions invariably stunt growth and limit the plant’s ability to reach its full height. Consistent moisture is also a factor, as sunchokes thrive in conditions similar to corn, making them responsive to regular watering; drought conditions will constrain their growth.
Controlling Vertical Growth
The impressive height of sunchokes often leads to a practical gardening problem: the risk of the tall, heavy stalks “lodging,” or falling over, especially in windy weather. Managing this excessive vertical energy is often a primary goal for gardeners trying to integrate the plants into a typical backyard setting. One effective strategy is to modify the plant’s natural growth trajectory through a technique known as “pinching” or “topping.”
This involves removing the main growing tip, or apical meristem, from the central stalk when the plant is still relatively young, typically reaching 12 to 18 inches tall. This action interrupts the plant’s hormonal signal for upward growth, redirecting its energy to lateral side shoots and promoting a bushier, shorter, and more self-supporting structure. The trade-off for this reduced height is that it may slightly reduce the total tuber yield, as less plant mass is available to photosynthesize and store carbohydrates.
For plants allowed to grow tall, support is needed to prevent them from collapsing onto surrounding garden beds. Staking individual plants with sturdy posts, or corralling a patch of sunchokes with twine or wire, provides the external reinforcement needed for stalks exceeding eight feet. Planting the tubers closer together than recommended allows the dense stand of stalks to lean on each other for mutual support against strong winds. If a plant has already flowered and reached its full height, the stems can be cut back to about 2 feet after the first frost to facilitate harvesting the mature tubers.