The night watchman did not see anyone this time. He walked through Caldecott Square at half past two on Sunday morning, noted nothing unusual, and continued his circuit. When he returned at a quarter past four, the large cast-iron planter beside the fountain contained marsh marigolds, meadowsweet, and wild thyme where it had previously contained municipal soil and a sense of patient expectation.

A handwritten note was pinned to the fountain railing with a dressmaker’s pin: “For the bees.”

It is the fifth such planting since late March. Cornflowers appeared on the 24th. Wild violets followed on the 1st of April. Primroses and foxgloves arrived on the 7th. Each time, the work was done between midnight and four in the morning, by a person or persons unknown, with soil, with care, and with a horticultural competence that Parks Superintendent Nora Quinlan has described — with an expression that suggests she is not entirely sure whether to be offended or impressed — as “better equipped than we are.”

Quinlan has stopped removing the flowers. This is not an official policy. It is the absence of one. After the third planting, she instructed her grounds crew to water the foxgloves. After the fourth, she added the marsh marigolds to the Tuesday watering schedule.

“I have a parks budget and a vandalism budget,” Quinlan said on Monday. “This falls somewhere in between. The flowers are healthy. The public appears to approve. I have, at present, no instruction from anyone to pull them up, and I am not inclined to volunteer.”

The public does appear to approve. The cast-iron planters of Caldecott Square have not received this much attention since the municipal gardening contract was reduced in 2019, a budget decision that left the planters filled with whatever the season provided, which was generally not very much.

But the most interesting observation has come not from the Parks Department but from the Polytechnic, where a twenty-six-year-old botanical illustrator named Patience Webb has spent the past week cross-referencing the Midnight Gardener’s plantings against the Polytechnic’s collection of pre-urbanisation botanical surveys.

“Every species planted in those beds,” Webb said, “is native to the Ashwater Valley meadowland that existed on the site of Caldecott Square before it was paved in 1834. Cornflowers, wild violets, primroses, foxgloves, marsh marigolds, meadowsweet, wild thyme — these are not garden flowers. They are the flowers that grew here before we did.”

Webb has located a botanical survey conducted in 1829 by one Aldous Pennick, a naturalist who catalogued the meadow flora of what was then called Caldecott Field. Pennick listed twenty-three species. The Midnight Gardener has planted seven of them.

“It is not random,” Webb said. “Whoever is doing this knows their Ashwater Valley ecology. They are replanting the square’s botanical memory.”

Whether the Midnight Gardener is working from the same survey, or from another source, or from the kind of knowledge that comes not from books but from a lifetime of watching what grows where — this is unknown. What is known is that the bees, at least, have noticed. Webb observed four species of native bee visiting the wildflower planters on Monday morning, including the brown-banded carder bee, which has not been recorded in central Bobington in a decade.

The identity of the gardener remains a mystery. The night watchman has seen a figure with a wheelbarrow once, on the night of the first planting. No complaints have been filed. No damage has been done. The notes — “More foxgloves please” and now “For the bees” — suggest a person of mild temperament, firm opinion, and excellent penmanship.

Quinlan, asked whether the Parks Department intended to investigate, considered the question for some time.

“I intend,” she said, “to water the meadowsweet on Thursday.”