Why does my moth orchid have wrinkled or shrivelled leaves?

On a moth orchid the leaves lose their firm, glossy, almost leathery look. They develop long pleats or puckers running along the blade, feel thin and limp, and may droop or fold.

The most likely cause, as the entry puts it, is that the roots cannot take up water, usually because they have rotted in wet bark. A moth orchid grows on tree trunks with roots exposed to the air, and bark that has broken down or stayed wet is not what it is built for. The NC State plant toolbox gives the same two possibilities: either the potting medium is being kept too dry, or the roots are damaged, often rotted by a soggy medium. The entry's rhythm is about 7 days in the growing season and 12 in winter, and the entry notes that wrinkled leaves on an orchid nearly always mean lost roots rather than lost water.

To confirm it in a minute, look at the roots through the clear pot. The RHS says healthy roots are plump, firm and silvery white, with green tips when growing. Brown, shrivelled, mushy or hollow roots are dead, and a pot with few live roots and wet bark is the answer. Lift the pot as well. If it is light and the roots are silver, the plant is simply dry.

Two other causes are worth ruling out. Bark that has been in the pot for more than about two years breaks down into something dense that holds water, and the RHS says this is when the roots start to rot. A pot with no drainage, or one standing in a saucer of water, drowns the roots in the same way.

Once roots regrow the leaves firm up, and that takes weeks to months, not days. Creases that have already formed in a leaf may stay, so judge the recovery by whether new roots appear with green tips and whether new leaves open firm.

What this plant wants

The fix

Tip the plant out, cut away every soft brown root, repot into fresh dry bark and water sparingly until firm green roots appear.

Read on

Wrinkled or shrivelled leaves

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

Moth orchid 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.