A well-designed herb garden in New England is one of the highest-value uses of garden space — high yield, low maintenance, and constant use from June through October. The key is knowing which herbs are built for northern conditions and which ones are fighting the climate all season.
The Reliable Perennials
Chives are the first herb up in spring and one of the last standing in fall. They're cold-hardy to zone 3, drought-tolerant once established, and will naturalize into a permanent clump that needs dividing every few years. Cut them back to an inch above ground after flowering to encourage fresh growth. The flowers are edible and excellent in salads.
Thyme is woody, drought-tolerant, and fully hardy in zones 5 and warmer. English thyme is the standard culinary variety. Give it full sun and well-drained soil — it will rot in wet conditions. Divide established clumps every 3 years when they become woody in the center.
Oregano is similarly hardy and drought-tolerant. Greek oregano has more flavor than common oregano — worth seeking out specifically. Cut it back hard after the first flush of growth in spring to prevent it from getting leggy.
Mint is aggressively perennial — plant it in a container sunk into the ground or it will take over the bed. Spearmint and peppermint are the most useful culinary varieties. Cut back to the ground each fall; it will return vigorously in spring.
The Annuals Worth Growing
Basil is the most important annual herb for the home garden and the most temperature-sensitive. It needs warm soil, warm nights, and full sun. Don't transplant until nighttime temperatures are reliably above 50°F — cold stress causes black spotting on the leaves that doesn't recover. Pinch flower buds immediately and continuously; once basil flowers, the leaves become bitter and the plant redirects energy to seed production. A well-managed basil plant in full sun can produce continuously from late June through September.
Parsley is a biennial grown as an annual. Start indoors 10 to 12 weeks before last frost — it germinates slowly. Flat-leaf Italian parsley has better flavor than curly parsley for cooking. Cold-tolerant once established; it will survive light frosts in fall and is often one of the last things standing in the garden.
Dill direct-sows easily and self-seeds prolifically. Plant successively every 3 weeks for continuous harvest. Let some plants go to seed for next year's volunteers and for the beneficial insects the flowers attract.
Cilantro bolts fast in heat. Sow early in spring, then again in late summer for fall harvest. Embrace the bolting — coriander seed is a useful spice, and the flowers attract beneficial insects.
The Borderline Cases
Rosemary is perennial in zones 7 and warmer, annual in most of New England. In zone 6 it sometimes overwinters with protection — a cold frame or moving a container indoors. In zone 5 and colder, treat it as an annual or overwinter it as a houseplant in a cool, bright location. Arp and Hardy Hill are the most cold-tolerant varieties.
Tarragon — specifically French tarragon, not the flavorless Russian variety — is a perennial that's hardy to zone 4 but goes dormant and disappears completely in winter, which leads many gardeners to think it died. It didn't. Mark its location and wait.
The Most Important Thing
Harvest herbs frequently. Regular harvesting keeps plants producing, prevents bolting in annuals, and keeps perennials from becoming woody. The gardener who harvests every week has better herbs than the one who lets plants grow to maturity before picking.
Whatever you're growing this season — grow it well.