Gunnera plants can become quite large and put on a showy display with their large leaves. Gunnera are popular for filling in large empty spaces in the garden and growing in soil unsuitable for other plants. Can the giant-leaved Gunnera be grown successfully in containers to display their spectacular growth?
Gunnera can be grown in containers, but it should be large enough to support the plant as it grows for several years. Larger containers such as half-barrels or old bathtubs are popular containers for growing Gunnera. For limited space, choose a smaller species such as Gunnera magellanica.
Growing Gunnera in containers can be done, but you should consider the plant’s needs and characteristics before limiting these plants to a container. Choosing the right container for your Gunnera plant and positioning it to provide the best growing environment will help the plant to thrive in a container.
Is Gunnera Good For Container Growing?
Gunnera are native to many locations, including central and South America, Africa, Madagascar, Indonesia, Hawaii, Australia, and New Zealand.
There are roughly 50 different varieties of Gunnera, and the size of the plant and the leaves vary from species to species. The stalks of certain species are edible, but the plants are generally grown for their beauty rather than their food value.
The two most common Gunnera species popular among gardeners for their large, impressive leaves are Gunnera manicata, sometimes known as Dinosaur Food, and Gunnera tinctoria, also known as Prickly Rhubarb.
The lobed leaves of these plants can reach an impressive 4 feet or 1 meter across, and the plants can reach 8 feet or 2 meters in height. Although Gunnera are flowing plants, they are grown for their leaf display rather than their flowers.
Best Gunnera To Grow In Containers
These are pretty large plants to grow in containers, but it can be done if you make the right choice in containers, growing medium, location, and care of the plant in the container.
However, the plants can become large and overwhelming when grown in a container, particularly if the container is located in an area with limited space.
Fortunately, there are smaller species of Gunnera, such as Gunnera Magellanic, which does not grow as large as the other giants and makes a perfect choice for container growing.
Best Containers For Growing Gunnera
Gunnera are perennial plants, meaning they can last several years planted in the ground or in a container. What this means is you should select a container large enough to support the growth of the plant over several years.
You can start the plant in a smaller container if your Gunnera is small and progressively transplant it into larger pots or containers as the plant increases in size.
Pots are a good choice as a starter container for Gunnera, and a pot of 8 or 9-inches or 20 to 23cm in diameter is a good choice for your young Gunnera. The pot can be clay or plastic but must have good drainage to prevent the roots from becoming waterlogged.
Other containers, such as half-barrels made from wood, are often used as natural-looking containers for growing Gunnera.
Many gardeners use old bathtubs for planting Gunnera to provide a larger space for the plant to spread out. If a bathtub is used, it should be positioned with the plug hole at a lower angle than the rest of the tub to promote drainage.
Best Soil For Growing Gunnera in Containers
Gunnera loves wet soil, which is why their natural habitat is near water, but this does not mean their roots should be in standing water.
Gardeners favor Gunnera for its ability to withstand wet soil much better than other plants. Gunnera are often planted in boggy soils where other plants would suffer from root rot, but the extra moisture causes the Gunnera to thrive.
Gunnera’s affinity for water has its limits, and the roots should not be allowed to stand in water or the soil in the container allowed to become waterlogged. The soil should always be moist but never waterlogged.
Consequently, the best growing medium for Gunnera in a container is a premium potting soil with added vermiculite or perlite for water retention and drainage characteristics.
Compost mixed into the upper layer of the soil helps with adding organic matter to improve the water retention and adding additional nutrients for the heavy-feeding plant.
Where To Grow Gunnera In Containers
Gunnera can be fairly fussy plants until they become established in the growing container, making it important to locate the container correctly to maximize the growth potential for the plant.
The container should be placed where the plant will be sheltered from the wind but where it receives about 6 hours of sunlight each day. If you live in a hot climate, a semi-shaded spot will be a good location choice for the plants, as excessive sun exposure could cause the growing medium to dry out quickly.
The biggest threats to Gunnera in containers are extreme heat, causing the plant’s roots to dry out, and excessive cold, including frost, which the plant has not evolved to handle well.
If you are growing Gunnera magellanica in containers, you will find that this species is more tolerant of drier conditions than its larger relatives.
How To Care For Gunnera In Containers
Gunnera requires a fair amount of care for them to thrive in a container. If the plant’s needs are not catered to in the growing environment, the plant will suffer and not produce the showy leaf growth you expect.
The large leaves produced by Gunnera require a rich fertile soil with high levels of nitrogen to provide enough food for the plant to generate and sustain the large leaves.
To provide enough food to the plants, you should fertilize your Gunnera frequently using a nitrogen-rich commercial fertilizer or a good quality compost to top-dress the growing medium in the container.
Fertilize your Gunnera every 4 to 8 weeks, or if you notice the plant’s condition declining, by renewing the organic compost mulch or feeding it a commercial fertilizer, following the manufacturer’s instructions.
Gunnera does not do well when the soil dries out and should be watered daily to keep the soil moist. One way to help with the moisture level when growing Gunnera in pots is to place the pot in a high-sided water tray.
Keep this tray filled with water to allow the soil in the pot to wick the water through the drainage holes and supply the moisture to the plant. This strategy may allow you to water the plant every second day rather than every day.
Since Gunnera prefers a mild tropical climate, they do not do well in cold winters and can be killed off by severe frost. In cold winters, the plant may die back, but a thick layer of compost over the crown will protect the plant from the cold, allowing it to grow back in the spring.
Conclusion
Gunnera are usually grown directly in the ground to fill gaps in the gardens and in locations that are too wet for other plants. Growing Gunnera in containers can be successful if the right size container is chosen for the plant.
Selecting a smaller variety of Gunnera will allow the plant to be grown in a smaller container and located indoors on a smaller balcony or patio area.
Place the Gunnera container in a sunny location but protect it from excessive heat and cold winters. Keep the growing medium moist and regularly fertilized, and your Gunnera will thrive in its container!
References
https://herbaria.plants.ox.ac.uk/bol/plants400/Profiles/GH/Gunnera
http://www.alternativeeden.com/2014/01/the-potted-life-of-gunnera.html
https://www.nature-and-garden.com/gardening/gunnera.html
https://forum.gardenersworld.com/discussion/1015388/gunnera-in-a-pot
