Why does my ZZ plant have long bare stems and pale new leaves?

On a ZZ plant this is a new stem that comes up longer, thinner and paler than the ones before it, with small, light green leaflets, and that leans or flops out of the clump rather than standing upright. The older stems keep their strong, upright shape.

The most likely cause is too little light. The ZZ does tolerate low light, even a room lit only by a north window or by lamps, and it does not decline there, but tolerating light is not the same as growing well. The entry says it grows faster in bright indirect light and that in a dark room it makes perhaps two new stems a year instead of five. The stems it does make reach for the light, and the further the plant is from the window the more they stretch.

To confirm it in a minute, put a new stem next to an old one and compare the length, thickness and colour. Then look at how far the pot is from the window and which way the new stems lean. If they all lean one way, the window is the cause.

Two other causes are worth ruling out. Winter shortens the day, so stretching that began in autumn on a plant that was compact in summer, in a spot that has not changed, is the plant doing its best with half the light. Too much nitrogen is the other, which shows as soft, floppy, oversized pale growth rather than thin growth reaching one way. The entry asks for only two or three half-strength feeds between spring and late summer, and none in winter.

Stems that have already stretched do not shorten. What you judge the recovery by is the new stems, which should come up shorter and stand on their own after a move to brighter light. For a plant that makes so few, that takes a growing season, so allow for it.

What this plant wants

The fix

Move it somewhere brighter, still out of direct sun. New stems then come up shorter and hold themselves upright.

Read on

Long bare stems and pale new leaves

The same sign on any plant, with the causes in the order they are likely.

ZZ plant care

Light, water, feeding, repotting and the rest of the entry.

Check it in the diagnoser

Opens with the plant, the part and the sign already chosen.