Why This Plant Should Stay Outdoors

We've had some recent visitors to our apartment, a constant trickle of black ants. Why are these insects here? What do they want? The answer is one word, "nectar."

Among our many house plants are several pots of Impatiens walleriana, commonly known as Busy Lizzie or Patient Lucy. These lovely flowering plants are known for their exploding seed pods, but these plants have another trick up their leaves. The edges of Impatiens leaves are lined with special structures called "nectaries." Nectaries are specialized glads that produce sugar-rich nectar to attract helpful pollinators like butterflies and bees. While these glands are usually found inside flowers, some plants also have extrafloral nectaries that form along leaves or stems. Nectar produced outside of the flowers is used to attract other beneficial, non-pollinating insects, such as ants, that protect the plant from pests in return for a sugary treat.

During the night, our Impatiens plants secretes orbs of nectar from their extrafloral nectaries. When the day begins, the droplets evaporate and leave behind chunks of crystalized sugar, effectively turning each leaf into the plant-world equivalent of a Frosted Flake. If you had an open container of Frosted Flakes sitting on the floor of your apartment, you'd have ants too.

The moral of the story is "You probably shouldn't grow exploding, sugar-coated plants in your house."

Brian Rutter, PhD, is the cofounder of Thing in a Pot Productions and a postdoctoral researcher in plant biology at Indiana University. Subscribe to our newsletter to receive our “Things About Things – Odd Facts About Plants” and video production tips in your inbox every month!

Works Cited:

Nicolson, Susan W., Massimo Nepi, and Ettore Pacini, eds. Nectaries and nectar. Vol. 4. Dordrecht: Springer, 2007.