Cicadas are coming, and an idea for containers

Q. I heard lots of cicadas will be hatching this year to make our summer very loud.

Billions of cicadas will buzz this spring as two broods emerge at the same time. These broods last emerged together in 1803 and won’t appear together again for 221 years, the year 2245. These cicada broods that appear in 13- and 17-year life cycles. Periodical cicadas have the longest known life cycle of any insect. Broods are groups of cicadas that share the same emergence years. Broods receive a number listed as a Roman numeral. Brood XIII only emerges every 17 years while Brood XIX emerges every 13 years. (Yes, I know, the Roman numerals do not match the year — go figure).

The last time these two particular broods emerged together was when Thomas Jefferson was president, decades before Missouri statehood. Emergence will occur in 18 Midwestern states. For the most part, most Missourians will only experience Brood XIX, the Great Southern Brood, which last appeared in Missouri in 2011. Expect them to emerge in late April to early May. Those in northeastern Missouri (as far south as St. Louis) near the Illinois border might see — and hear — both broods.

Cicada nymphs stay in the soil for 13 or 17 years, depending on their brood. They emerge when the soil warms to 64 degrees, usually right after a spring rain, and dig their way out of the ground. They subscribe to the “safety in numbers” approach and emerge all at once. They climb trees, fence posts or anything vertical before shedding their hard skins. Then they head to treetops to mate, lay their eggs and die within four to six weeks.

Those in northeast Missouri can expect to see a lot of them — as many as 1.5 million per acre, which creates a feeding frenzy for predators and litter so heavy that the sidewalks and highways may need shoveling.

The loud sound you hear is from male cicadas as they send out their mating call, which can be as loud as a lawnmower and is unique to its species.

Cicadas, while loud and messy, are harmless to humans and their pets. They don’t sting or bite. Don’t use pesticides that will harm birds and beneficial insects such as butterflies, bees and moths. If there is concern about new trees or bushes, protect them with a loose cover of cheesecloth.

Q. I had a plant recommended to me for containers, called Persian shield. What can you tell me about it?

Persian shield (Strobilanthes dyerianus), is an annual that is cultivated for its deep purple, iridescent, lanceshaped foliage. The stems and veins are dark green, while the tissue between the veins is metallic purple.

It grows to about 18” high and wide, and is a great upright plant for container gardens, in flower beds, or even as a houseplant. It wants part to full sun, is very heat and drought tolerant. It is easy to grow and needs little care.

Persian shield does have shortlived blooms. Try planting these next to variegated lime-green to chartreuse-leaved plants or ones with lots of flowers. It is not preferred by deer nor rabbits. It is typically propagated by cuttings taken early spring or summer which root easily in water or moist growing medium.

Readers can pose questions or get more information by calling 417-8742963 and talking to one of the trained volunteers staffing the Master Gardener Hotline at the University of Missouri Extension Center in Greene County located inside the Botanical Center, 2400 S. Scenic Ave., Springfield, MO 65807.