There are many species of thistles (thistle). These plants of the family of Asteraceae are, for many of them, considered as harmful plants with a very strong power of dissemination having a considerable impact on the balance of ecosystems. This is the case of field thistle (Cirsium arvense). Moreover, the law requires its destruction according to article L251-3 of the Rural Code. Here’s how to do it for successful weeding.
Know how to recognize the Thistle of the fields
Also called Cirse of the fields, this very common thistle in Europe is classified as an extremely invasive weed. It develops rapidly in wastelands, ditches, meadows, cultivated fields and of course in gardens because it has a great capacity to adapt to various environments.
The wind spreads its seeds up to 150 meters around, and a single thistle can produce up to 40,000 of which about 300 end up germinating and what should be noted is that they are able to keep their germination capacity up to twenty years. This thistle with branching stems, which can reach 1.50 meters in height, is recognizable by its pretty lilac-coloured tubular flowers which exhale a pleasant fragrance. Its rhizomatous roots sink into the ground up to 2 meters deep to draw essential nutrients and water.
In our country, the Field thistle is declared pest because it is responsible for a loss of yield for farmers. This is why many prefectural decrees force a merciless fight against this Cirse des champs.
Eradicate the Thistle: beware of prohibited herbicides
As expected, if one lets oneself be invaded by the Thistle, it will be very difficult to eradicate it completely because, as we have specified previously, its seeds can germinate several years after having been dispersed by the wind. One may be tempted to resort to a synthetic herbicide to get rid of this weed, except that since 1is January 2019 (date of entry into force of the Labbé Law or Law 2014-110) amateur gardeners (and not only) no longer have the right to use (or even possess) chemical pesticides.
To eradicate the Field thistle, we have no choice but to use the products authorized in Organic Farming provided they are stamped Authorized Use in the Garden (EAJ) or even some biocontrol products or even those said low risk. It is therefore essential to be well informed when purchasing a treatment against thistles, especially since the use of a prohibited herbicide (which would have been kept in the depths of a cupboard) is an infraction. criminal. The offender is liable to severe penalties, namely a fine of €150,000 and 6 months’ imprisonment. We do not mess with the health of the environment.
Avoid being invaded by Thistles: means of prevention
Field Thistle can be prevented by using the following solutions.
- Ask a geotextile where one wishes for example to create massifs.
- Cover the areas where the thistles develop with plates of carton or some plastic sheeting. Deprived of light, the Cirses will find it difficult to develop.
- Install a mulch at the foot of cultivated plants to leave little chance for the Thistle to grow.
- sow luzerne on the plot so that the plants compete. Clover is able to deprive thistles of water and nutrients.
- Let it settle thistle fly and various species of charançons which devour the Thistles.
It is best not to leave a corner of bare soil in the garden because this unwanted plant is likely to settle there quickly.
Mechanical thistle control: the alternative to chemical herbicides
Fortunately, there is still a solution to avoid being invaded by thistles without resorting to dangerous weedkillers. This is the mechanical struggle which combines various tasks, namely:
- The manual uprooting of all the thistles in the garden,
- Repeated mowing and grassland mowing,
- burning,
- The burial of stubble or dethatching, which is rather reserved for the field of agriculture, for example after harvest.
The Field Cirse being a plant particularly tough, the gardener who is invaded by it must arm himself with patience so as not to see a single Thistle in his garden. This is why it is strongly recommended not to allow this weed time to settle.
Here is how to proceed to eradicate the Field Thistle.
- Cut the thistle stems close to the ground using pruning shears after taking care to put on gardening gloves. Ideally, this pruning is carried out as soon as possible so that the plant does not gain strength. If you have a lot of thistles (wasteland, meadow not mown for a long time or neglected garden), it is essential to pass the mower.
- Repeat pruning or mowing as soon as the Thistles grow back to weaken plants since their roots will gradually run out of nutrients.
- Digging the earth in order to get out as much as possible of roots.
- Burn all the thistles cut as well as the roots dug up so as not to risk a new proliferation. This waste should therefore not be added to the compost.
It is of course possible to overcome this plant by spraying it regularly with horticultural vinegar (inedible) which gets rid of this weed in a few hours. But this solution is only valid if you don’t have many thistles in your garden. As to sel d’Epsom to distribute all around the feet of Cirse, it is to be used sparingly because it prevents many plants from growing and does not only kill weeds. So be careful…
It is very important to intervene either before floweringthat is pendant the flowers are in full bloom. But if we wait for them to dry, the seeds will form and sow the garden as well as all the surrounding land… Similarly, care must be taken to remove the entire root because the smallest piece left in the ground enough for the Field Thistle to regrow. By leading a fierce mechanical struggleit takes two to three years to permanently eradicate the Thistle.