The Corydalis Flexuosa Story

The story opens in 1989, on a plant expedition in Western China, where three Englishmen -- James Compton, John d'Arcy and Martyn Rix -- are hunting for plants.

"Frustration mounts as they are driven through dappled woods past startling sheets of blue, until the reluctance of their Chinese hosts to pause and allow the team to inspect the plants so inflamed their bladders that an urgent stop was insisted upon, during which time three small pieces of (Corydalis) rhizome were secreted in a moss-lined film canister..." A certain amount of subterfuge was necessary to ensure their introduction.

To say the least, the secret's out. Over the past thirtyone years, those three stem snippets have been propagated into untold millions under three cultivar names: "Purple Leaf", "Pere David" and "China Blue."

Each makes a low-growing, compulsively tidy ground cover with finely dissected foliage, topped by a cluster of upright, spurred blossoms that could turn turquoise to envy and rival the colour of Paul Newman's eyes.

The differences among the three are subtle but worth noting, though all are choice woodland plants. "Purple Leaf" has the best year-round foliage, with dark stains at the base of each leaflet. Though somewhat less electric than the other corydalis, it's unfazed by winter and the earliest to bloom.

"Pere David's" rich, turquoise-tinged flowers are the largest of the trio (mind you, we're talking eights of an inch), nodding above blue-green foliage on mahogany stems. This one can produce sizable colonies, spreading by underground stems. "China Blue" is the truest and brightest shade of a New England winter blue sky, and asks the same cultural conditions: light shade, rich soil and adequate moisture.

With the floodgates now open, nurseries are increasingly awash in this bleeding-heart-family plant (which means prices are coming down. Of late, there's "Blue Panda," awarded the highest azure prize of all for flowers that are Meconopsis (blue poppy) blue. Also check out the straight species, C. elata, which is taller and more upright than C. flexuosa with purple air-brushed flowers. If you're low enough to the ground, you'll find them sweetly fragrant too.

Bloom time for all these baby blues is anywhere between March and June, then perhaps October and, who knows, maybe into winter. Impressive, but I wouldn't say they're unstoppable, since a number will go dormant in summer and disappear without a trace. It's a little unnerving if you've a rotten memory, so consider leaving their tags in the ground. Film canisters will work, too.