Mature size & growth rate

How big does Winter Tarragon (Tagetes filifolia) get?

Also called Irish Lace Marigold, Filigree Marigold.

More about winter tarragon

About Winter Tarragon

Tagetes filifolia · also called Irish Lace Marigold, Filigree Marigold · herb

Tagetes filifolia, sold as winter tarragon or Irish lace, is a tender marigold relative from Mexico and Central America. It forms a mound of finely divided, thread-like bright green foliage that smells of anise and licorice, used as a tarragon substitute. Tiny pale flowers appear in autumn. It needs warmth and full sun to thrive.

Mature size: Typically 30-50 cm tall and about 30 cm wide, occasionally larger in a long warm season.

Watch for — Leggy growth in low light: Insufficient sun stretches the stems and thins the lacy foliage. Give full sun or supplemental grow lighting to keep it dense and fragrant.

Indoor size vs how big it gets in the wild

Winter Tarragon reaches its full size within one growing season — there is no "long-term" size, just how big it gets before you harvest or it dies back. Indoors and in a pot, expect typically 30-50 cm tall and about 30 cm wide, occasionally larger in a long warm season.. A pot, your light levels and a little pruning are what set the final size in a home, far more than the plant's theoretical potential.

It sizes up fast and once, racing from seedling to full size in a single season; after cropping it is finished, so size is a within-season question.

Growth rate and years to mature

Winter Tarragon is a moderate grower. Realistically, expect a single growing season — it reaches full size in one year, then is done. Its feeding profile backs this up: feed sparingly. a balanced liquid feed at half strength every 3-4 weeks in the growing season is plenty. like most marigolds, rich nitrogen gives lush leaves but fewer flowers and weaker scent.

Want this turned into the right next pot at the right moment? The pot size calculator and the winter tarragon repotting guide cover when and how much to size up — pot size is one of the biggest levers on how fast winter tarragon grows.

How to keep winter tarragon smaller

You are not stuck with the maximum size. For winter tarragon specifically, these are the levers, in order of impact:

Choose a compact or dwarf variety of winter tarragon from the start — that is the most reliable size control for an annual.
Grow it in a smaller container to naturally limit how large it gets.
For some crops, pinching or pruning the growing tips keeps the plant shorter and bushier.
Sow a little later or space plants closer if you specifically want smaller individual plants.

How to grow winter tarragon bigger or faster

If you want it to fill the space sooner, push the conditions rather than hoping — for winter tarragon the accelerators are:

Full sun, warm soil and steady water are what drive a crop to full size fastest.
Sow at the right time for your zone so it gets the whole season to size up.
Feed appropriately for the crop and never let it check (stall) from drought or cold.

Light is almost always the ceiling. The winter tarragon light requirements page covers exactly how bright a spot it needs to grow at its potential instead of stalling.

When winter tarragon outgrows the room (or the pot)

"Too big" usually arrives as one of these signs for winter tarragon:

It sprawls beyond its bed or container before harvest — usually a spacing or support issue.
It flops or needs staking once it hits full height.
Once it has fruited or bolted, it is at its final size for good — the next plant is a new sowing.

If it is the pot rather than the room, it is a repotting job, not a goodbye — see the winter tarragon repotting guide. If you want more of this plant instead of a bigger one, the winter tarragon propagation guide turns prunings into new plants.

Winter Tarragon size — frequently asked questions

How big does winter tarragon get?

Winter Tarragon reaches typically 30-50 cm tall and about 30 cm wide, occasionally larger in a long warm season. when grown indoors. It sizes up fast and once, racing from seedling to full size in a single season; after cropping it is finished, so size is a within-season question.

Is winter tarragon slow or fast growing?

Winter Tarragon is a moderate grower. Expect a single growing season — it reaches full size in one year, then is done. Winter Tarragon reaches its full size within one growing season — there is no "long-term" size, just how big it gets before you harvest or it dies back.

How long does winter tarragon take to reach full size?

Roughly a single growing season — it reaches full size in one year, then is done. Light, pot size and feeding move that timeline more than anything else.

How do I keep winter tarragon smaller?

Choose a compact or dwarf variety of winter tarragon from the start — that is the most reliable size control for an annual. Grow it in a smaller container to naturally limit how large it gets. For some crops, pinching or pruning the growing tips keeps the plant shorter and bushier. Sow a little later or space plants closer if you specifically want smaller individual plants.

How can I make winter tarragon grow bigger or faster?

Full sun, warm soil and steady water are what drive a crop to full size fastest. Sow at the right time for your zone so it gets the whole season to size up. Feed appropriately for the crop and never let it check (stall) from drought or cold.