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Easy Tips on How to Grow and Care for the Gunnera Plant

How to Grow and Care for the Gunnera Plant
The most distinctive feature of the Gunnera plant is its large leaves. This large-leaved perennial grows best in the USDA hardiness zones 6 to 8. Gardenerdy focuses on the varied aspects of Gunnera plant care, ranging from its light requirements, soil type, to watering needs.
Smita Pandit
Last Updated: Apr 28, 2018
Knowing Gunnera Closely
The genus Gunnera comprises 40-50 species that have foliage, which varies greatly in size. While the lobed foliage of Gunnera manicata grows up to 7 feet in width and 11 feet in height, Gunnera albocarpa has leaves that just measure 1-2 cm in length.
The Gunnera genus is named after Johan Ernst Gunnerus (1718-1773), a Norwegian botanist. It is endemic to certain regions of Central and South America, Australia, New Zealand, Southeast Asia, Africa, and Madagascar. The species that are placed under this genus are herbaceous flowering plants that belong to the Gunneraceae family. Gunnera manicata, which is native to southeastern Brazil, is one of the popular species that has been given the Award of Garden Merit by the Royal Horticultural Society. This herbaceous plant is mainly grown for its huge leaves. Needless to say, gardening enthusiasts who are planning to include Gunnera manicata in their garden should ensure that their garden is large enough to accommodate this plant. This plant is likely to thrive in the USDA hardiness zones 6 to 8. It grows well in warm weather. If you want this plant is flourish, make sure to provide it a damp environment.

Though Gunnera manicata is also called Giant rhubarb, its leaves are not edible. In fact, this plant must be handled with care, as under the large, leathery umbrella-shaped leaves lie spikes. Spikes are also present along the stems. The stalks of Gunnera tinctoria, which is also called Chilean rhubarb, can be consumed.
Gunnera Plant Information
Large Leaves of the Gunnera Plant
Gunnera plant
Genus: Gunnera
Family: Gunneraceae
Class: Magnoliopsida
Order: Gunnerales
Scientific name: Gunnera manicata
Also Called: Giant Rhubarb, Dinosaur food
Plant Type: Perennial
Leaf Type: Large, lobed leaves
Foliage Color: Green
Width of Foliage: 7 feet or more
Height: Up to 2 meters
Spread: 5 feet
Habit: Clump-forming
USDA hardiness zone: 6 to 8
Soil: Moist, loamy soil
Soil pH: 6.1 to 6.5
Light Requirements: Full sun to partial shade
Watering Requirement: High moisture
Ideal Growing Conditions for Gunnera manicata
Gunnera manicata Plant in a Botanical Garden
Brazilian plant Gunners
Closeup of the Foliage of Gunnera manicata
Gunners manicata
Large Stalks and Leaves of Gunnera manicata
Gunners manicata
Plants from Gunnera genus are water-loving, which is why they are more likely to thrive when they are planted on the edge of streams or ponds. Moist soil is indispensable for the growth of this plant, which is why Gunneras do very well in bog gardens. Here are the other conditions that you need to provide for ensuring proper growth of Gunneras.
Growing Gunneras from Seeds
If you are planting gunnera seeds, you must understand that the process of germination is slow. Temperature ranging between 75°C and 85°C works well for germination. The germinated sprouts can be planted during spring. All you need to do is dig 4-inch holes in a place where the soil remains moist, preferably at the edge of a pond or stream. You can also create a bog garden. It is extremely essential to enrich the soil with manure or compost. You can also apply a slow-release fertilizer. Make sure that the planting site is not exposed to dry, cold winds. Protect the plant from frost during winter. Choose a site where the plant will receive sun to partial shade.

An easier method would be to purchase a Gunnera plant. Make sure that you plant it only after the danger of frost has passed. You can also propagate through division. The best time to divide is spring. If you are using a bulb, place it at least 6 inches below the surface. In case of species that produce large foliage, there should be ample space between plants, so as to allow the roots to grow. If you wish to put the plant in a pot, make sure that you use a large-sized pot, so that there's enough space for the root system to grow.
Light and Temperature
Gunnera plants grow well in sun, as well as partial shade. However, it is believed that the plants placed in partial shade are more likely to have bigger leaves. This plant prefers warm weather. The plant should be protected from cold, dry winds.
Soil Type and Watering
This plant grows well in moist soil. It prefers loamy soil that is rich in nutrients. Thus, it is advisable to amend the soil with organic matter. The soil should be very moist. In the growing season, Gunnera manicata requires a lot of water. In fact, the soil must remain moist at all times. This is the reason why, the best place to plant a Gunnera plant is along the edge of a stream or a pond. Plant it right after the last frost in spring. Reduce the frequency of watering during winter, as that can make the plant susceptible to root rot.
You will need to amend the soil often to ensure proper growth of this plant. Mulch it well with organic mulch and manure. You can use a balanced (10-10-10), slow-release fertilizer. Do follow the directions provided by the manufacturer regarding the application.
Care During Winter
During winter, the crown of the plant should be protected. Cover it with a thick layer of mulch or dry leaves. In case of established plants, the large shoots and foliage can be cut down to within 12 inches of the root ball. These can be piled over the crown every fall.
On a concluding note, the key to keeping the Gunnera manicata plant healthy is to provide it with moist soil that is enriched with organic matter and fertilizer. Another important aspect is to protect it from dry, cold winds. Gunnera plants will surely be a welcome addition to your garden, provided you fulfill the aforementioned requirements.