Rough Chervil is one of several Umbellifers which all look quite similar. Thus it is easily overlooked or mistaken for Cow Parsley.
These photos were all taken in France, I have recently been on the lookout for Rough Chervil growing in the UK but so far have not found any, to be honest I have not been desperate to find any as I knew I had some photos and felt that sooner or later I would come across some growing in a hedgerow or woodland margin in my Wye valley area.
As you can see it is somewhat more delicate than Cow Parsley, also the stems can have a reddish purple colour. You can see this lower down on some of the stems in the photo. This purple colouration can sometimes be in the form of blotches, and thus look a bit like Hemlock. Also as you would expect from the name the stems have a rough feel to them.
Rough Chervil is also poisonous along with Hemlock, though perhaps not quite so deadly. The sap can cause blistering on the skin and were you to eat any then symptoms similar to drunkenness are supposed to ensue. Cattle and other grazers sometimes eat it and then suffer. There is of course another Chervil which is a garden herb, not one of the top five of herbs as it is not that useful. It has a delicate flavour with a hint of licorice and is used in the French fines herbes mix also as a substitute for parsley. Anyway make sure you do not muddle up Chervil and Rough Chervil.
It flowers from May through to July, by which time it will have reached a height of about 100 cm, so not the tallest of the group. Generally a little later to flower than Cow Parsley It is a biennial species, so is fairly reliant on producing a good number of seeds each year to maintain its population, as such it is not suited to the dark conditions of woodlands and so is restricted to the margins. It will also grow in rough grassland. It is not so keen on very wet soils or acidic soils.
The flowers are quite attractive to various insects especially hover flies which by crawling across the surface of the umbell pick up pollen and thus transfer it from flower to flower, plant to plant.
The flowers are smaller and more dainty than Cow Parsley also they strike me as more brilliant white. like the adverts for washing powder where they used to have a a super white shirt with a backdrop of slightly grey /white shirts. Here are two more photos of Rough Chervil, as I said, taken some years ago in France…..