What is a weed?
That is the first question a gardener must be able to answer but it is a very simple answer. A weed is simply a plant growing somewhere you do not want it to grow and usually it has grown there by itself. It likes where it has planted itself.
Wild flowers are considered weeds by many people, but some of of the nicest flowers are wild flowers. They can be considered weeds if they reproduce freely in your garden and become a nuisance. Everyone knows the Dandelion (Taraxacum officinale agg.) but my favourite is the Common Dog-Violet (Viola riviniana).
Common dog-violet (Viola riviniana)
Luckily there is a great website where you can learn all about Irish wildflowers (or weeds) – http://www.irishwildflowers.ie/
The Oxford Dictionary definition of noxious is harmful, poisonous or unpleasant.
Thistle, Ragwort, Dock, Wild Oat and Male Wild Hop Plant are classified as noxious weeds in Ireland. It is the responsibility of the landowner to destroy them – on penalty of the paltry sum of twenty pounds (under the 1936 Noxious Weeds Act).
For instance, ragwort is poisonous to horses. It remains in the horses liver and accumulates over time and just that one last mouthful might be their last.
Invasive weeds are a more serious matter.
Invasive weeds are plants not native to Ireland which have been brought into the country inadvertently with other cultivated plants or they have been purposely brought in as a desireable garden plant but were later discovered to be less than desireable – to be invasive. These plants grow so rapidly that they destroy the native flora and therefore are a serious threat to the biodiversity of Ireland.
Invasive weeds commonly spoken about in the media are Japanese Knotweed (Fallopia japonica), Giant hogweed (Heracleum mantegazzianum) and Himalayan Balsam (Impatiens glandulifera). However, there are many more serious ones which are invading Ireland’s water systems, choking the native plants and using up all the oxygen so that all life is destroyed.
You can read all about invasive species in Ireland at this very comprehensive website: