Gunnera tinctoria and Gunnera manicata are commonly referred to as Chilean rhubarb, giant rhubarb or dinosaur food and belong to the Gunneraceae family. Growing naturally in the high forests of both Central and South America, these plants will thrive in USDA Zones 7 to 10. Gunnera plants can grow to heights of 8 feet or above with widths up to 12 feet, and these plants produce massive leaves. Caring for Gunnera starts at planting.
Plant your Gunnera in partial sun or shaded areas and near water, if possible. Choose locations with moist, rich soil and enough room for the full size of the Gunnera to mature. Remember to wear gloves when working with your Gunnera plant because of the sharp spines.
Water your Gunnera plant as needed to maintain moist soil conditions throughout the growing season. Cover the area around the plant with 3 to 4 inches of mulch to help maintain the damp conditions needed and prevent weeds.
Apply a basic fertilizer, such as 10-10-10, each spring or early summer to your growing Gunnera, and then drench the area with water. Follow the directions on the label for proper amounts.
Cut the Gunnera back to ground level each fall or cover the top of the plant with several inches of straw for protection through the winter months. Some gardeners remove the giant leaves, place them over the rest of the plant and then add the mulch on top of the leaves.