Tarragon

French tarragon (Artemisia dracunculus var. sativa) is one of the few culinary herbs you cannot grow from seed. Seed packets labeled “tarragon” are invariably Russian tarragon (A. dracunculus var. inodorus or simply A. dracunculus) - a plant that looks nearly identical but tastes like almost nothing. If you’ve grown “tarragon” from seed and wondered what the fuss was about, that’s why.

French tarragon is a sterile triploid - it produces no viable seed. The only way to get it is from a division or cutting of an existing plant. Expect to pay $3-6 for a rooted division from a reputable herb nursery. That $3.49 listed as seed cost in the data above represents the cost of a division purchase.

What it actually is

French tarragon is a perennial in USDA zones 4-7, dying back to the ground each fall and re-emerging in spring. It grows 18-24 inches tall with narrow, lance-shaped leaves that smell unmistakably of anise and slightly of vanilla. The flavor is assertive - a little goes a long way in cooking. It is a foundational herb in classical French cuisine: béarnaise sauce, fines herbes, tarragon vinegar.

The distinction from Russian tarragon matters at the garden center. Russian tarragon has slightly serrated leaf margins and duller green color compared to French; it may also have tiny flowers that set seed. French tarragon almost never flowers in temperate gardens. When in doubt, crush a leaf and smell it - Russian tarragon has nearly no scent; French is unmistakable.

The ROI case

Fresh-cut tarragon retails at $12-18/lb (USDA AMS Specialty Crop Market News, 2023). A standard grocery store clamshell contains roughly 0.3 oz for $2-3 - that’s $107-160/lb equivalent. The plant itself, once established, asks almost nothing from you after the initial purchase.

A mature French tarragon plant yields 0.15-0.35 lb per season across multiple harvests. At retail replacement value, one plant returns $2-6 per year - modest against a single harvest, but this is a perennial. That same plant runs 5-7 years before vigor declines, at which point you divide the root clump and restart with no additional purchase. The cost per ounce of fresh tarragon you actually use drops to near zero by year three.

Growing requirements

French tarragon does best in well-drained, moderately fertile soil at pH 6.0-7.0. It tolerates lean soil better than rich, wet soil. In heavy clay, root rot is common - amend or plant in a raised bed.

Plant in full sun. Partial shade produces thin stems and weaker flavor. Space plants 18 inches apart; mature plants spread 12-18 inches via rhizomes.

Tarragon requires a cold dormancy period to thrive long-term. This is why it struggles in zones 8+. Without the annual reset of a cold winter, plants exhaust themselves and typically decline after 2-3 years. Zone 8 growers can extend plant life by mulching heavily in summer to keep roots cooler and dividing the clump every two years.

Water at 0.5-1 inch per week during active growth, less once the plant establishes. Good drainage is more important than regular water - saturated roots cause rot regardless of the season.

Do not over-fertilize. High nitrogen produces lush, watery growth with diluted flavor. A single application of balanced fertilizer (10-10-10) in early spring when shoots emerge is sufficient. Many growers apply nothing at all after year one and get excellent results.

What goes wrong

Root rot from poor drainage is the primary failure point. If a plant dies back in summer rather than fall, check the roots. Mushy, brown roots indicate a drainage problem. Plant in a slightly raised position to help excess water move away from the crown.

Powdery mildew (Erysiphe sp.) develops in humid, low-airflow conditions late in the season. It rarely kills the plant but reduces harvest quality. Remove affected foliage and improve airflow. The plant will die back naturally in fall anyway, so serious summer mildew mostly affects that season’s late harvests.

Rust (Puccinia dracunculi) produces orange-brown pustules on leaves. It’s uncommon but can defoliate a plant in a wet season. Remove affected leaves and apply sulfur fungicide preventively in seasons with wet springs.

Crown rot in fall or early spring occurs when mulch is applied too heavily over the crown itself (rather than around it). Keep mulch 2-3 inches away from the emerging crown in spring.

Harvest and storage

Begin harvesting once plants reach 8-10 inches tall in spring. Cut stems 3-4 inches from the growing tips. Harvest regularly to encourage new growth and prevent the plant from becoming woody. Don’t take more than one-third of the plant at a time.

Fresh tarragon keeps 1 week refrigerated wrapped in damp paper towels. For longer storage, freeze whole sprigs - they lose texture but retain flavor for cooking. Tarragon dries poorly because the volatile compounds responsible for flavor dissipate quickly with heat; if you must dry it, use the lowest possible heat and store in an airtight container.

Tarragon-infused vinegar is the best preservation method for long-term use - it captures the flavor effectively and keeps for 6-12 months.

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Related crops: Chives, Arugula

Related reading: Companion Planting Basics - what the evidence actually says about common herb pairings