PEOPLE born after 1980 have been slower than previous generations to settle down. Some want to explore the world before they get married and have kids. Others simply cannot afford to buy a house. But they can afford houseplants, and many are finding that nurturing them is a more manageable form of domesticity.

Since the turn of the century, exports of plants from the Netherlands—by far the world’s biggest producer of plant life—have increased from $6bn in 2000 to $9bn in 2016. In that year Europeans spent some €36bn ($42bn) on houseplants and flowers. And in America, millennials are thought to account for fully one-third of the houseplant sales. Amazon, the world’s biggest online retailer, began selling plants last year, and direct-to-consumer start-ups like Patch and The Sill have cropped up, delivering leafy goods in pretty pots to doorsteps everywhere.

Interest in houseplants as measured by internet search data has closely tracked the surge in sales. The number of Google searches for succulents has risen tenfold since 2010, and other green plants have had similar spurts of popularity. The data are highly seasonal: interest blossoms in the spring but is relatively dormant by December.

What explains the growth in greenery? Young people are more likely than their elders to live in city flats without gardens. Although houseplants grow and require care, they are neither as demanding nor as costly as pets or children. Instagram, a viral photo-sharing platform, can be credited for causing a spike in interest in cacti and other plants: #plantsofinstagram boasts 1.6m photographs—double that of a previous millennial fad, #avocadotoast.