Did you know that all plants, even if in the slightest way, have the ability to move? We’re not talking about the obvious types of movements plants make that can be fully explained, like a Venus flytrap catching its prey or sunflowers growing toward the sun, but rather a routine reflexive occurrence called nyctinasty or nyctinastic movement. Think flowers opening and closing, leaves drooping and lifting. Plants move for a reason. So why does it happen and how exactly does it work?

What is nyctinastic movement and why do plants do it?

In the plant world, nastic movement refers to responses to external stimuli. Nyctinasty, also known as sleeping movements, specifically describes plant movements in the absence of light.

So what happens when the lights go out? Just like all living things, plants follow a type of circadian rhythm. When the sun rises, they rise — and maybe surprisingly — when it sets, they sleep.

What does sleeping look like for a plant? In some cases they droop down, petals close, or leaves fold.

Why do they do it? There’s no definitive answer though some hypotheses point toward temperature control, protection from insects or herbivores, or even “preventing the disruption of photoperiodism by moonlight”.

How does it work?

While plants don’t have muscles that contract and expand like mammals, they do have joint-like clusters of cells at the base of their leaves called pulvinae which can swell or shrink thus causing movement.

Types of nyctinastic plants

No, all plants are not nyctinastic. Though some hypotheses may suggest that nyctinasty in plants may hold some evolutionary benefits. So what plants do close-up shop when it gets dark? Legumes, prayer plants, tulips, and more.

Care of nyctinastic plants

Speaking about the prayer plants like Maranta and Calathea, care is relatively easy. These plants actually get their name for their nyctinastic tendencies. During the day they sport flat, outstretched leaves while at night the leaves fold up as if they may be praying. Because these plants are native to Brazil/Central & South America, they prefer conditions that closely resemble their native humid environments and do best in medium to bright-indirect light exposures.