The huge sum is more than treble the amount paid for greenery by the next most extravagant department, the Ministry of Justice.
Stretched public finances in 2007-08 failed to sap the department's enthusiasm for plants, with spending on foliage up by 83 per cent in a year that saw a teacher pay rise of just 2.5 per cent.
The spurt of growth coincided with Ed Balls' arrival last summer. But his officials say it is because of plants bought as part of a "one-off" building refurbishment rather than a penchant for foliage by the schools secretary.
The bill - enough to pay three teachers' salaries - was unearthed by Mark Hoban, Conservative MP for Fareham in Hampshire. He has made a habit of asking Government departments about their spending, on everything from flowers to first-class rail tickets, as part of a campaign for greater efficiency.
"I think headteachers who find it increasingly stretching to manage their budgets will wonder whether the DCSF has got the right spending priorities," he said.
A spokesman for the department said the figure should be set against pound;8 million saved by moving its London staff to a single building and the 50 per cent rise in school budgets.
But Mick Brookes, general secretary of the National Association of Head Teachers, said: "I can imagine the criticism that heads would get if they spent money that could be going to frontline services on pot plants for their offices.
"But it does mean there is more oxygen in the air at Sanctuary Buildings in Westminster, and that can only be a good thing."