Gadenin日本語Get the appWhy you cannot grow the good tarragon from seed
French tarragon does not set viable seed. It flowers sparsely, the flowers rarely open properly, and nothing fertile comes of them. Every French tarragon plant in cultivation descends by division and cuttings from existing plants, which is why it costs more as a plant and why you will never find it on a seed rack.
This is the single most useful fact about the crop. If a packet says tarragon seed, what is inside is Russian tarragon, a different and much tougher species that germinates readily, grows twice as vigorously, tolerates cold and wet, and tastes of almost nothing. Gardeners who report that their tarragon is huge, easy and disappointingly bland have grown the Russian kind without realizing it.
The test takes one leaf. Pick a mature leaf, chew it, and wait. French tarragon gives a clear sweet anise flavor followed by a faint tingling numbness on the tongue. Russian tarragon gives a mild green grassiness with no anise and no tingle. Do this before you spend a season propagating a plant, because everything below multiplies whatever you already have.
| Feature | French tarragon | Russian tarragon |
|---|---|---|
| Sold as | Rooted plants only | Seed packets and cheap plants |
| Leaf when chewed | Sweet anise, then a tingling numbness | Grassy, faintly bitter, no tingle |
| Leaf appearance | Narrow, glossy, deep green | Broader, duller, paler, often coarser |
| Habit | To about two feet (60 cm), lax | Taller and coarser, often three feet (90 cm) or more |
| Seed | None viable | Sets readily and self-sows |
| Toughness | Dislikes wet and cold; short-lived | Very hardy and long-lived |
If you already have Russian tarragon, it is not useless. It is simply a bulk herb rather than a fine one, and it is better used young, as the flavor of older leaves is worse still.
Division: the reliable method
Division is the standard way to increase French tarragon and it doubles as the maintenance the plant needs anyway. The right time is spring, as soon as new shoots are showing at the surface but before the clump has put on much height. The roots are shallow, brittle and creeping, so work with a fork rather than a spade and lift more soil than you think you need.
Expect fewer, larger divisions than you would take from a clump-forming grass. Three to five good pieces from a three-year-old plant is a realistic result, and each of them should carry both visible shoots and a fair share of root.
- Lift the whole clump Fork all round the plant at least six inches (15 cm) out from the shoots, then lever it up whole with as much root as you can hold together. Do not pull it out by the stems; they snap off the crown.
- Discard the middle Shake off the loose soil and look at the center. On any clump three years or older it will be woody, dead or hollow. Cut it out and throw it away. The propagating material is the vigorous outer ring.
- Pull the outer ring apart Tease the outer sections apart with your hands, cutting only where they will not separate. Aim for pieces the size of your fist, each with several healthy shoots and pale live roots. Anything with soft brown roots goes on the compost pile.
- Replant immediately Replant at the same depth as before, eighteen inches (45 cm) apart, in a spot with grit worked in and better drainage than the plant came from. Firm gently and water once. Do not water again until the surface has dried.
- The first fortnight Keep divisions out of hot direct sun for their first week if you can, shade them with anything to hand in a heatwave, and pick nothing from them for at least six weeks.
Softwood cuttings: more plants from one
Cuttings give you far more plants than division, and they are the safe move when a valued clump is showing signs of rot and you want insurance. Take them in early summer from soft new growth, before the stems have gone hard and woody. Late-season cuttings from tough stems root badly.
Cut shoots four to six inches (10 to 15 cm) long in the morning while the plant is full of water. Strip the leaves from the lower half, trim the base just below a leaf joint, and get them into a gritty mix within minutes; tarragon cuttings wilt fast and a wilted cutting rarely recovers.
Root them in a mix that is at least half sharp sand or perlite, in a covered tray or a pot inside a clear bag, in bright light out of direct sun. Keep the mix barely moist rather than wet, and air the cover daily so the foliage is not sitting in condensation. Expect roots in three to five weeks, shown by resistance when you tug a cutting very gently.
Growing on and keeping notes
Pot rooted cuttings individually into a free-draining mix and grow them on under shelter through their first winter, keeping them nearly dry once they die back. A first-year plant has a small crown and very little reserve, and it is the one most likely to be lost to a wet cold spell outdoors. Plant them out the following spring once growth restarts.
Record the date you took each batch of cuttings, how many you took, and how many rooted. Rooting success in tarragon varies a lot with the softness of the wood, and after two seasons your own notes will tell you the fortnight in early summer when your plants strike best. Also record which parent plant each batch came from, because you are cloning a specific plant and you want to keep propagating from the one that actually tastes right.