False Nettle (Boehmeria cylindrica) for Butterflies
False Nettle is a host plant for a few butterflies including the Red Admiral, Question Mark and the Eastern Comma butterfly. A host plant is a specific plant that butterflies lay their eggs on to feed their caterpillars.
Growing False Nettle
Boehmeria cylindrica is a perennial that dies back in the fall to return each spring. It is native throughout Eastern, central and Southwestern states in the United States and up into Eastern Canada. It does not have any stinging hairs unlike its relative, stinging nettle (which the butterflies listed above also use for a host plant). So it is a good plant to add to a butterfly garden without the worry of gloves and handling.
False Nettle is not much of a nectar plant since its summer flowers are rather inconspicuous. It is listed as growing about 2-3 feet high but in my sunny southern garden it is about 4-5 feet high. It is hardy from zones 4-10 and prefers moist to wet areas with some shade. When growing naturally it is usually found in wet areas, however, it can adjust to medium-moist conditions once established. In my southeast garden it required water periodically during the first year or two after planted. But now it does fine with no watering unless there is a particularly long dry spell.
A single plant of False Nettle will grow into a clump over the years and with pruning it will be considerably more bushy. I planted 4 plants (about 2 feet apart) to make the “shrub” seen in the above left photo.
A Butterfly Host Plant
Boehmeria cylindrica attracts three butterflies in particular:
- Red Admiral Butterfly
- Question Mark
- Eastern Comma
These three butterflies have other host plants that they will use as well but the False Nettle is one that can fit nicely into a garden setting (unlike stinging nettle or the trees that some of these butterflies use).
Although the Question Mark and the Eastern Comma butterfly will use False Nettle (they may have a preference for Elm trees if available), it will most likely be frequented by the Red Admiral butterflies. Red Admiral butterflies are widespread and can be found from Canada all the way down through the US into Central America.
Red Admiral butterflies lay their eggs near the tender top growth of Boehmeria cylindrica. After the caterpillar hatches out of an egg, it will make a leaf nest. Although the eggs are difficult to spot, the leaf nests give the caterpillar away. If you see the some ragged looking leaves at the tip of the new growth then there is most likely a caterpillar hiding in there!
In the picture to the right you can see how the leaves look chewed up. Sometimes the caterpillars roll leaves but in this case the caterpillar has pulled the smaller leaf down to attach it to the leaf below making a place to hide in between the leaves. The picture to the left-below shows the young Red Admiral caterpillar (and its frass – caterpillar poop) when the leaf is lifted.
When the caterpillars pupate they normally do not leave the plant like many other caterpillars do. Instead they make a large leaf nest on the plant and pupate inside it. False nettle is a very easy plant to raise caterpillars on indoors (or elsewhere) because the cuttings hold up very well in water.
If you want to bring them indoors you simply need to put several cuttings in water and they will stay very good for a long time while the caterpillar eats and grows. As an added bonus, this caterpillar does not usually wander as long as you provide cuttings with enough larger leaves to make an appropriate leaf nest in the cuttings.
Growing False Nettle Seeds (or Cuttings)
False nettle is very easy to propagate from cuttings. It will readily root in water or soil. When I put cuttings in water for the caterpillars they always grow roots while the caterpillars are eating.
From seed: start indoors 6-8 weeks before last frost. Surface sow False Nettle seeds and keep the seeds and the seedlings very moist. The plants are very tiny upon emerging so you may want to use a mist bottle to keep from damaging them. A plastic top would help keep in the moisture. Growth is slow until they reach about 1-2 inches at which time they will take off. When planting outdoors, space the plants about 2 feet apart.
NOTE: seed should be stored dry in the refrigerator until you are ready to plant – this aids germination. Our seeds for sale are kept in cold storage.