Chervil

Chervil is a French herb that most American gardeners meet once, plant in May, watch bolt by June, and never try again. The problem is not the gardener or the seed — it is the season. Chervil is a cool-weather plant with a narrow tolerance for heat and bright sun. When temperatures climb above seventy degrees and the days lengthen past fourteen hours, the plant sends up a flower stalk and the leaves turn bitter. By the time most gardeners think to plant herbs, chervil's productive window has already closed.

The fix is to plant it when you would plant spinach or lettuce — four weeks before your last frost in spring, or in late summer for a fall harvest. In many climates, the fall crop tends to be more reliable because the plant matures into cooling weather rather than warming weather. A sowing in mid-August often gives you harvestable leaves by late September, and the plant may hold through light frosts if mulched.

Chervil must be direct-sown where it will grow. Transplanting damages the taproot badly enough that the plant usually sulks for weeks or bolts immediately. Scatter seed thinly in a row or block, cover lightly with soil, and keep the surface damp until germination — usually seven to ten days in cool conditions. Thin to six inches once the seedlings have a few true leaves. The thinnings are edible.

Shade matters more than most herb guides admit. Full sun in a typical summer garden is too much light and too much heat for chervil; the leaves bleach, the flavor coarsens, and the plant races to seed. Planting in the dappled shade of taller crops — under a tomato canopy in spring, or on the north side of a trellis — can extend the harvest by several weeks. A spot that gets morning sun and afternoon shade is often ideal.

Harvest by cutting outer leaves as soon as the plant is six inches tall. The more you cut, the longer it tends to stay in leaf production, though once a flower stalk starts to form the leaves lose their delicate anise flavor and the plant is finished. At that point, let it flower — the tiny white umbels attract beneficial insects — and pull it when it dries. Chervil self-sows readily if you let a few plants go to seed in place.

In mild-winter climates, chervil can be grown as a winter herb outdoors; in colder regions, it performs well as a windowsill crop if started in a pot in late summer and brought inside before the first hard freeze. The flavor is more subtle than parsley, with a faint licorice note that fades when cooked, so add it fresh at the end of a dish or use it raw in salads.