The fields are glowing yellow this week. Not just because
the sun is shining, it’s also the time for ragwort to flower.
Tansy ragwort (Senecio jacobaea) is seen as one of the most
harmful plants that grow wild and if left to self-seed in its second year can
take over a field in next to no time.
Biennial Ragwort
Tansy ragwort is a biennial plant which means that it takes
two years for it to complete its lifecycle. It grows as a ground-hugging
rosette in its first year. In its second year of growth, it transitions into
its mature, tall, flowering form. Ragwort
plants produce a lot of seeds which can remain viable in the soil for a few
seasons. If left to spread, it can form
dense patches, either from seed or by vegetative reproduction when its roots or
crown are injured and new shoots develop making it extremely hard to control.
Controlling ragwort
Tansy ragwort can be controlled manually by digging or
pulling in spring and summer before they flower. Rosettes should be dug up,
removing as much as the root as possible. All pulled plants could be bagged and
placed in the municipal waste for recycling into compost or burned. Once plants
bloom you will have about three weeks until the seeds form to take action.
Mowing is not a good control for ragwort. While it may
prevent the plant from immediately producing seeds, it also stimulates
additional vegetative growth. This leads to more plants and more stems per
plant in the same season. Mowing is especially problematic in pastures, where
it can spread the leaves, making it harder for grazing animals to avoid.
Chemical control is favoured by some folk.
In the agricultural depression of the 1930s and during the
Second World War, there was far more Ragwort around than there is today. There
were no selective weedkillers available, so it had to be controlled either by
hand-pulling or by allowing sheep to graze off the young plants, which are less
poisonous. There were also many more horses in the country, working on farms or
pulling delivery vans. Ragwort poisoning was a recognised disease, but not a
major problem.
Ragwort types
Ragwort (Senecio Jacobea) is also known as ragweed,
buachalán and buachalán buidhe. It is a common weed of Irish pastures and
thrives on a wide range of soils, but competes best on lighter free draining
soils where fertility is reasonably high and grazing not intensive.
There are four main types of ragwort to be found in Ireland
according to An Irish Flora (1996) namely:
Common Ragwort
-Senecio jacobaea - found everywhere.
Marsh Ragwort
Senecio aquaticus - wet fields, marshes
Ragwort - Senecio
squalidius - mainly in larger cities, rare elsewhere.
Ragwort - Senecio erucifolius – found especially
in Dublin and Meath.
All four can interbreed where both parents are found.
Ragwort – Virtues
It’s not all doom and gloom for the plant, it does have its
virtues –although it’s a very divisive subject and some will disagree,
especially horse owners.
At least 30 species of insects and other invertebrates are
totally dependent on ragwort as their food. Many other species of insects either
eat ragwort, or require the nectar and pollen from the flowers. Ragwort is a
major nectar source for many insects, including bees, hoverflies, butterflies
and moths.
Make a bit of Money
Entrepreneurial youngsters can make quite a bit of money
hiring their weed pulling services out to farms and large private home owners.
You could make a few euro clearing areas of the plant before they go to seed.
There would be a payoff for the farmer too as they would get a better price for
their hay after harvesting.
Whatever the myths and scare stories about this widely
disliked plant are, it’s here to stay. It
is very easy to create hysteria about ragwort, those not familiar with
scientific methods can often be misled into believing that it poses a much
greater threat than it does. Don’t believe everything you read – even in this
article, I could be talking a load of nonsense as usual.
