Tuesday 25 April 2023

Invasion of the Few Flowered Leek.

 Few Flowered Leek/Garlic  - Alium paradoxum,  is well established in the north west corner of the Park. See the area marked in red.



This plant is a native of the Caucasus and probably came to this country along with imported potted plants. In our case, it may well have come from the Rivers Nursery where it is also established. It is an almost perfect invasive species . It does not have proper flowers and does not need pollinating in order to reproduce, instead, it produces firstly a prolific number of 'bulbils' in the flower head and secondly offsets from the main bulb in the ground. Nothing eats it (apart from humans!) because it has a strong smell and is distasteful. And lastly, it forms such dense clumps that it shades out any other plant including native ones which should be there.

The 'flower' and bulbils.



Bulbs in the ground and 'offsets'.



Masses of bulbs in the ground lead to a very dense clump which excludes other vegetation.




Invasion starts, presumably from a is single bulbil from a flower. Initially there is a single leaf but as the bulbs multiply in the ground the size of clump steadily increases. A single bulbil in the centre of native Dogs Mercury will soon overwhelm the plant that should be growing there.





Where this plant is growing is the oldest section of woodland on the Park and probably pre-dates the Park itself. If we value the native woodland flora then not trying to control it is not an option. Efforts so far have included hand digging and pulling- it comes up quite easily and cutting with a hand scythe and collecting up the leaves and flowerheads which may weaken the bulbs and will prevent bulbils falling on the ground. It will be best to try and remove plants near to the path because it is known that the bulbils can be transported on boots and dogs paws.  A realistic solution might be to not work on eradication but to limit the spread by making it one of the Work Party tasks on an annual basis. A survey of the native flora will be carried out so we have got a baseline to work to.