Top of The Crops - Tarragon

Growing Tarragon In A Polytunnel

Growing tarragon, especially the coveted French Tarragon, is an excellent choice for culinary enthusiasts, including polytunnel gardeners, who relish cooking with homegrown herbs. 

Beyond its culinary applications, tarragon offers digestive benefits, making it particularly suitable for pairing with oily foods. The aromatic leaves boast a delightful licorice or anise-like flavour, perfect for both fresh use and drying for future culinary endeavours. Tarragon plays a pivotal role in classic sauces like béarnaise and holds significance in herbal medicine.

Moreover, tarragon serves as a magnet for beneficial wildlife in the garden, fostering a healthy ecosystem. Additionally, it is reputed to repel certain pest species while providing shelter for beneficial invertebrates, contributing to a harmonious and balanced garden environment.

Key Information

There are two primary types of culinary tarragon: French tarragon and Russian tarragon. French tarragon, formally known as Artemisia dracunculus var. sativa, is widely regarded as the superior herb for culinary purposes. It holds a prominent place among the fines herbes of French cuisine and complements various dishes, including chicken, fish, and egg-based recipes.

On the other hand, Russian tarragon, sometimes considered a variant of Artemisia dracunculus or referred to as Artemisia dracunculoides, exhibits a milder flavour compared to its French counterpart.

However, it compensates with its hardiness and robust growth characteristics. Russian tarragon spreads via its roots, thrives in neglectful conditions, and can tolerate poor soils and drought. While it may not excel as a culinary herb, Russian tarragon finds utility in other applications and is sometimes cultivated in areas where French tarragon struggles to thrive.

In the UK, French tarragon is typically the preferred choice for cultivation. Although it is a short-lived perennial herb, typically producing for only a few years, it can be propagated to ensure a continuous supply.

When to Plant and How To Grow Tarragon

Follow the table below to know when to plant and how to grow tarragon in the UK.

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Plant
Harvest

The Preferred Conditions for Tarragon 

Both varieties thrive in large pots filled with gritty compost. Additionally, Russian tarragon can flourish in free-draining soil when planted in a sunny and sheltered location. Whether in containers or in the ground, providing well-draining soil and ample sunlight is key to successful cultivation of both types of tarragon.

Sowing

French tarragon cannot be grown from seed, so it's best to purchase young plants in the spring season. Conversely, Russian tarragon is easily cultivated from seeds, although young plants can also be acquired.

French tarragon, a perennial herb prized for its culinary qualities, typically does not flower or produce seeds reliably, making it uncommon to grow from seed. When tarragon seeds are available for purchase, they often pertain to the lesser-quality Russian tarragon variety. Therefore, those seeking to cultivate French tarragon usually opt for pot-grown plants, obtainable in spring.

These young tarragon plants are typically transplanted into larger pots filled with a well-draining growing medium. Alternatively, they can be planted directly into free-draining garden soil in a sunny and sheltered location. This ensures optimal growing conditions for French tarragon, allowing it to thrive and provide an abundant harvest of flavourful leaves for culinary use.

Sowing indoors

If you choose to grow Russian tarragon, you can sow seeds indoors to transplant later into your garden, or sow directly where the plants are to grow. 

When sowing tarragon seeds, it's important not to cover them and to sow them sparingly, as one plant typically suffices. Optimal germination occurs at temperatures ranging from 15–20°C and may take several weeks to occur.

Once the seedlings have reached a sufficient size for handling, transfer them into individual pots or modules. Place them in a warm and brightly lit area, ensuring regular watering to promote healthy growth. Once the seedlings have developed strong roots and are growing robustly, they can be safely planted outdoors in a suitable location.

Sowing outdoors

If indoor sowing isn't feasible due to time or space constraints, you can opt to sow Russian tarragon seeds directly outdoors in a warm and sunny location during late spring. 

Simply scatter the seeds on the surface of the soil without covering them, once temperatures consistently reach at least 15°C. This method allows for straightforward cultivation of Russian tarragon without the need for indoor seed starting. But be sure to protect your tarragon from slugs and snails. 

Planting

Whether you choose to grow superior French tarragon or the Russian variety, selecting the right growing location is key. 

Tarragon thrives in warm, dry, and sunny locations with well-drained neutral or slightly alkaline soil. It is commonly cultivated in dedicated herb gardens alongside other Mediterranean herbs that share similar growing requirements, such as rosemary, lavender, marjoram, oregano, and thyme.

However, it can also be advantageous to strategically place tarragon—whether in the ground or in containers—around the crops in your kitchen garden. Doing so can attract beneficial wildlife and contribute to organic pest control, enhancing the overall health and productivity of your garden.

For planting tarragon in the garden, select a site with excellent drainage and ample warmth and sunlight. Avoid areas prone to frost pockets and waterlogging, as tarragon roots are susceptible to rot in wet or heavy soils. Plant outdoors in spring once the weather has reliably warmed and frost risks have passed. 

In containers

When growing tarragon in a pot, opt for a container that promotes dry and free-draining conditions, as the flavour of the herb is reputed to be enhanced under these circumstances. A terracotta pot is ideal for herbs that prefer drier and more free-draining environments.

Fill the chosen container with a peat-free multi-purpose compost enriched with horticultural grit to ensure adequate drainage. Place a crock at the base of the container and use a pot stand to facilitate proper drainage. When transplanting tarragon into the container, maintain the same planting depth as in its previous container.

By adhering to these guidelines, you can ensure optimal growing conditions for your tarragon plants, whether in containers or in the garden.

Care Tips for Tarragon 

Tarragon is somewhat more challenging to grow than many other common culinary herbs, but if you are conscientious and understand where to position it and how to provide it with the right care, this can go a long way towards achieving success.

Watering

While tarragon thrives in well-drained soil, it's crucial to avoid complete drying out of the growing medium, particularly when cultivating tarragon in pots. Young plants and those in containers need more frequent watering compared to mature ones in soil. 

Consistently water throughout the growing period, being careful not to overwater. Ensure plants aren't sitting in water during heavy rainfall or due to excessive watering to prevent root rot.

Light

Tarragon will require a position in full sun in order to thrive. It cannot grow well in overly shaded conditions. 

Soil

This herb needs a free-draining soil or growing medium. In many ways, this is one of the most important elements when caring for tarragon successfully in your garden, especially if French tarragon is what you have decided to grow. 

Temperature and Humidity

Temperature fluctuations through the growing season are generally well-tolerated by this resilient plant. Even during cold snaps, its growth tends to persist. However, tarragon struggles in environments of intense heat, sunlight, and high humidity.

French tarragon is not fully hardy and will need winter protection, or an undercover location for the coldest part of the year. Russian tarragon is a hardier plant that can make it through the winter outdoors in the British isles. 

Mulching

Mulching around tarragon plants with organic matter can help to provide the right conditions, and can also help keep weeds down. 

Winter Protection

French tarragon teeters on the edge of hardiness, requiring placement in a sheltered spot during winter or relocation indoors in colder regions. Shielding the plant with a cloche or horticultural fleece can be beneficial when tarragon is left in place, and a mulch of carbon-rich material like wood chip or autumn leaves will help protect the roots. 

Despite above-ground growth dying back each autumn, new shoots typically emerge in spring if the roots endured the winter unscathed. 

Waterlogging, rather than temperature, tends to pose the primary threat, making it advisable to transfer tarragon to an unheated polytunnel or greenhouse, or a cool porch during the coldest, wettest periods if you have been growing outdoors. Additionally, situating pots in the rain shadow of a wall or fence can offer protection.

Propagating

As previously noted, French tarragon is typically not reliably propagated from seeds. However, once you possess a tarragon plant, you can expand your stock, replace tarragon, and ensure a continuous supply of this beneficial herb by dividing mature plants at the roots. Keep in mind that although tarragon is a perennial, its vigour diminishes after several years, necessitating the replacement of older plants with new ones.

During autumn, select a mature, sizeable tarragon plant in a container. Extract the plant from its container and carefully divide the root ball in half. Replant one portion, using fresh peat-free multipurpose compost mixed with grit, and divide the remaining portion into several root cuttings.

Trim the top growth from your root cuttings and prune any thin, straggly roots to ensure each cutting can be accommodated in a module or small pot. 

Take care to avoid damaging the main creeping rhizome, which stores energy for next year's growth. Subsequently, pot these root cuttings and lightly water them. Label them accordingly, then position them in an unheated greenhouse, polytunnel, or cold frame over winter before transplanting them outdoors the following spring.

Pruning

It is beneficial to trim back or harvest approximately half of your plants around June to promote ongoing growth. If you notice flower buds starting to emerge, promptly remove them to encourage continued leaf production.

Harvesting

You can harvest tarragon leaves at any point during the growing season, ensuring a continuous supply. Leaves will keep coming as long as the plant avoids flowering. 

Storing Tarragon

Freezing tarragon leaves is the optimal method for preserving them for future use, although they can also be dried and stored. Additionally, tarragon leaves can be used to create excellent vinegar so this is something else to look into if you have the time. 

Preparation and Uses

French tarragon is extensively utilized for its flavouring, fragrance, and medicinal properties. With its subtle taste, it complements a variety of dishes including fish, beef, chicken, asparagus, eggs, and soups. It is used raw and cooked in a range of recipes, and is also utilised in herbal medicine and is said to have a range of health benefits. 

Troubleshooting

If there is something wrong with a tarragon plant, the first thing to do is to look at the environmental conditions and care you have provided. Most frequently, when something is amiss, this is due to problems with the environmental conditions or care. 

Varieties of Tarragon

Remember, one of the decisions that you will have to make if you want to grow tarragon is whether you will grow French tarragon or Russian tarragon. Russian tarragon is considered easier to grow and is more hardy, but French tarragon is more highly prized for culinary use. 

Common Problems for Tarragon 

Tarragon is prone to slug infestations, particularly in the early stages of growth or when plants are small. Vigilance is key, as these pests can decimate entire plants if left unchecked. Handpicking slugs, implementing physical barriers, and encouraging natural predators in your garden are effective organic methods for slug control.

Furthermore, tarragon is susceptible to fungal infections such as powdery mildew and rust. To mitigate these issues, avoid overcrowding plants, ensure proper drainage, practice appropriate watering techniques, and opt for cooler growing conditions. Promptly remove any affected plant material and dispose of it carefully to prevent the spread of infection.

Top Tips for Growing Tarragon in a Polytunnel 

A polytunnel will make it easier to grow this herb successfully in the UK, and other polytunnel crops may well benefit from having this herb growing close by. 

FAQs

Can you grow tarragon in the UK?
Is tarragon a perennial plant?
Where is the best place to plant tarragon?
Why is tarragon so hard to find?

Sources

Enloe, A., (2022) 8 Surprising Benefits and Uses of Tarragon. Healthline. [online] Available at: https://www.healthline.com/nutrition/tarragon-benefits-uses [accessed 21/03/24]

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growing tarragon in a polytunnel