Rosemary; that's for remembrance, thinks John. The cliche slips in, supple, unbidden as a cat. He turns it over.

Fragrance waxes greenly from crushed leaves, dark pointed needles, pale underneath. This has nothing to do with me, John thinks, or Sherlock, who saw plants only as he saw people: ciphers of complex chemicals, more or less volatile, more or less inert. Capable of being deduced.

Verbinol, camphor, linalool; the relentlessness of resins, clinging stickily to the skin. Evergreen perennial; likes sun. The stems go woody in winter, waiting for spring. Grows well from cuttings; plant deeply, keep moist. Watch your grief change, as it flares out roots and wavers in the wind, all raw, and soft, and new.

Medicinal properties: thymoleptic, stimulant, circulatory, nervine. A cordial plant, help for the overthinking head. If it had come to us earlier, thinks John. It could never have been enough.

To his medical mind the plant makes no sense. Only: the flowers are blue, the colour of eyes. Sherlock's eyes, John thinks, and closes his own. It will ward the dreams from your bed. He doesn't believe it.

It works, anyway.