Gunnera Growing Instructions and Plant Care
Gunnera Growing Instructions and Plant Care
Don't be concerned if the root ball has been smashed a little in shipping, this will not affect the plant, the main thing is that the roots have not dried out in shipping. If a leaf tore off, or some soil came off of the roots that also should not be a problem. Gunnera's will grow if the root ball and the crown were not separated. It will take several weeks for the new leaves to regrow under normal situations. In Winter months, after the first near freeze, plants may have their large leaves pruned back.
In hot weather, water immediately on receiving. New plants need to be watered daily if your temps are over 70 degrees during the day with 50 degree nights during the growing season.
In cool or cold weather where the temperature is at or below 45 degrees during the day, do not water until plants dries out. Too wet soil will root rot and kill the plants during this period.
The 3 things that will kill young gunnera is drying out in hot weather, planting in full sun, and too much water with poor drainage that will rot the roots. Gunneras are easy to kill...so don't just plant.
On small plants a hour or two of direct morning sun or dappled sunlight is okay. DO NOT use commercial potting mixes (Miracle Gro®, Vigero®, etc.) They are intended for annuals and will rot Gunnera roots, thus killing the plants. Your potting soil mix should include the following: 10% compost, 10% peat moss, 10% perlite, 35% bark chips and 35% pumice, lava, or some small stone in the potting mix. If you do not add the pumice or rock, when you water the mix could be too wet and not drain well enough and this could cause the roots to rot and the plant to die. If planting in a naturally wet area, plant on a mound or raised bed. Gunnera plants need a lot of space and are difficult to restrict their size, so don't plant near other plants, or close to buildings. We guarantee delivery of live healthy plants, but are not responsible if you kill the young plant by planting in full sun, or water too little or water too much with too little drainage.
Gunnera also need to be watered daily during the hot summer until the plants have roots at least a foot deep. Mature Gunnera need a compost heavy/peat amended garden soil with pumice or small stones that stays moist, but not soggy. They need a steady moisture supply during the hot spring and summer months, but good drainage especially during the wet season & in the winter when the plant is dormant. You are recreating a bog that drains well, where the gunnera plants are 2 to 2.5 feet above the saturated wet area.
Special Winter Care for young plants. Do not plant outside if your temps will be below freezing for the winter. Instead plant in a larger container and keep in an area that is between 30 - 70 degrees. Often planting the plant in a 2 gallon or larger container for a season to grow and develop will increase your success. Use a planting mix with good drainage...compost, peat moss, bark, perlite, and pumice. Then in the second year transplant to their permanent location before they leaf out in the spring. This is especially important if your permanent location is in 1/2 day or near full sun. Make sure the fertilizer you are using is meant for containers or it will burn the leaves. A variation of temp is better than a constant temp. The area should be well lit. Use a fast draining potting mix as recommended above. If you cannot find it locally, we have it available on our website. Unheated rooms have a higher humidity and are better than rooms heated by a furnace or wood stove, because the humidity is too low. Moisten the potting mix, but do not have it soaking. Then plant. In several days when the leaves show water stress water in well. Then do not water until the leaves show water stress again. This can be as often as every week or every 3 weeks. As your temps warm in the spring you will go back to every other day or every day watering. Over watering will cause root rot in young plants and can kill the plant.
Over the winter your gunnera should double or triple in size! If your winter indoor temperatures are 70 degrees during the day and 45 degree nights.
Plant outside in the spring when the chance of freezing weather is over. The plants will root out by fall and will be hardy to USDA Zone 7.
Special Winter Care for mature plants Cut down the leaves after the first frost in the fall and place the leaves over the crown. If your winter's temps are below 15 degrees add 8-12 inches of dry loose mulch around the crown. Always cover the crown and cover with a tarp or waterproof material to keep the crown dry during the winter. Remove mulch and cover in the early spring.