Do you have a large garden that needs something unique? Then you should try gunnera. Gunnera grows 8 ½ feet high, 10 to 13 feet wide and its rhubarb-like leaves can grow well over 42 inches wide. In the summer, it produces a tall spike of greenish flowers. If planted in the right spot, gunnera is not difficult to grow. It's suitable for USDA zones 6 to 8.
Select the site for gunnera. It grows in semi-shade and sunlight in cool, damp areas. They need rich, moist soil; planting it near a pond or stream helps with this requirement. It can also be planted in a bog or water garden. Dig up the soil, remove rocks and other garden debris and mix in plenty of organic matter several weeks before planting.
Plant gunnera in the spring. Dig a hole that is larger than the container. Remove the plant carefully from the container and put it in the hole. Fill the hole with soil and tamp down gently to remove air bubbles. Water to settle the soil. Mulch the crowns with a heavy layer of decayed manure or compost to protect it while it is settling in.
Water gunnera regularly and deeply. Apply pelleted manure as new growth appears. Mulch with a fresh layer of decayed manure at the same time. There are no specific pests of diseases associated with this plant.
Watch for heavy spikes of greenish flowers beginning in the early summer. Fleshy red-green fruit, which can be ornamental, follows. As the weather cools in the fall, cut off the drying leaves. Cover the crown of the plant with a thick layer of straw and use a large leaf as a hat to keep it dry.
Propagate gunnera by dividing in the spring. Dig up the plant, divide the clump and replant. Space no closer than 6 ½ feet apart.
Handling gunnera may cause skin irritation or allergic reaction. It also has spines or sharp edges; use extreme caution and wear gardening gloves when handling.
Tips and warnings
- Handling gunnera may cause skin irritation or allergic reaction. It also has spines or sharp edges; use extreme caution and wear gardening gloves when handling.