Some plants that we grow can reap big rewards but come with some risk. The risk might involve substantial cost when success is doubtful, or the plant might be a beauty but it usually succumbs to insect or disease attacks. Other plants are so invasive that although beautiful, the effort needed to keep them contained is immense and not always successful.
One invasive plant to consider “risk and reward” before planting is Chinese lantern. It spreads like wildfire by underground rhizomes and if not contained will completely take over. There are a couple of ways to grow this without it getting out of hand; the first involves having an appropriate location and the second is using containers.
If you have a spot in the landscape where the plant can be allowed to spread without invading another gardening space, then growing Chinese lanterns can be undertaken — perhaps along a bin or shed, or along a gravel driveway where the plants will be confined between the driveway and grass. If they do grow into the driveway a bit they are easily pulled up.
The other method of growing Chinese lantern so that it cannot escape is to grow it in containers. These can be large nursery pots that can be buried in the ground to make it appear that the plants are actually growing in the ground. This procedure involves a bit of effort and if the pots have drainage holes (which they should have) there is no guarantee that the rhizomes won’t find these and escape to invade the surrounding soil. Also, because the pots inhibit the roots’ ability to seek moisture, they will have to be watered regularly. The pots can be overwintered in place, but the longer they are maintained in the same spot, the more likely the rhizomes are to escape the containers. It might be a good idea to move the pots to a different location each spring and to carefully examine the empty hole after the pot is removed to make sure no rhizomes are on the loose. Rather than using pots, some kind of barrier might be installed, but it must be substantial and extend deeply enough into the soil so that the rhizomes cannot grow under it.
Chinese lanterns can be propagated by division or grown from seed. The seeds require light to germinate so don’t cover them with planting medium. The plants are easy to grow — not fussy about soil fertility and are drought tolerant, but do like full sun. The stiff stalks have heart-shaped leaves and the plants produce insignificant white flowers at the leaf axils. These blooms are gradually encased inside papery pods, called calyxes, which initially are green but in the fall turn yellow and then a bright orange red. The plants are not overly tall, rarely getting more than 50 cm in height.
The main reason Chinese lanterns are grown is for the attractive papery seed cases that are so colourful and attractive. When they have matured to a deep orange, they can be harvested, usually in September. The stalks can be cut off at ground level and the leaves removed. Some people bundle several stalks together and hang them in a cool, dark place to dry for several weeks. I’m always anxious to use the lanterns as soon as they are harvested, so I snip off the leaves and use the lanterns right away and they dry naturally after they have been arranged. The pods in this case will hang down. If the stalks are hung upside down to dry, the pods will point upwards, so if you dry before using and want the pods to hang down naturally, dry them upright by placing the stems in containers.
Is the risk of planting Chinese lanterns in your landscape worth the rewards you’ll receive in the fall? If you decide that it is, make sure you take appropriate precautions so that you don’t end up regretting the day you ever planted Chinese lanterns in your garden!