you dig it out before it seeds it will spread, as it is very much at home in a fertile garden soil.
Thankfully it is not poisonous to the touch, although I do recommend gloves. It is the roots that are dangerous, and digging them out is the only effective control. Composting will not do – this is one for a hot bonfire.
Identification is not the easiest as there are many members of this family ( Apiaceae, which includes celery, carrots, parsnips, hogweed etc) that look similar. It is an erect clumpforming perennial with light green foliage and flat-topped white flower umbels that appear in early summer. The foliage, as with many in the family is slightly “cut” or jagged.
Perhaps the most noticeable thing of all is the smell of the crushed foliage – sickly sweet and pungent.
Then there are the roots. They look like a bunch of thick white carrots and remind me of the dead man’s fingers inside crabs that, as children, we were taught to remove if a violent death was to be avoided. Surprisingly, the plant is easy to dig up. Staying with the Apiaceae family,
(Heracleum sphondylium) is a native weed that will burn you only, it seems, if you are allergic to it. My neighbor, an avid scyther, was taken by surprise when working barefoot and was blistered very badly. However, it is not poisonous to eat – indeed it is beloved of foragers. Do not confuse it with close relation the ( which is a natural-born killer. The sap burns and is deadly if ingested.
There is no mistaking giant hogweed when mature as it is 6ft 6in (2m) tall, with huge white flowers. The leaves are cut like those of the common hogweed and hemlock, rough to the touch but dark green to the common hogweed’s much lighter green; a similar shape but bigger.
( is an annual weed in the same family as garden busy Lizzies. It has pretty pink flowers and a sweet smell. And that is where the pleasantness ends. It is often bracketed with Japanese knotweed because it colonises and takes over, bullying other plants out of the way with its strong-arm tactics.
However, it is not a deep rooter and comes out easily when dug or pulled. Do this before it flowers to prevent its spread. At the end of July it is an experience to find yourself in a grove of balsam to witness the seedpods exploding and firing their contents all around you.
Another exploding seed spreader is the (
Luke Hazelton, nursery manager at Trewithen in Cornwall, names this innocuous little annual as his weed of nightmares. Coming to fruition in late spring, it too is famous for firing out its ripe seeds.
The problem for Luke is that the weed colonises containerised plants and once the seed stock is in the pots the weeds keep germinating. However, hairy bittercress is easily hoed off on dry days.
or mare’s tail ( is on a par with Japanese knotweed in its capacity to root deeply and withstand chemical treatment. It increases by two methods, spores and rhizomes. The spores have jumping “legs” that are activated by humidity, and the rhizomes travel as deep as 6ft 6in (2m) underground. Not bad for a
Be gone: Tom Petherick shows off the impressive root system of water hemlock, left; oxalis, centre; Tom digs out a stem of horsetail, below