Perfoliate alexanders

Early on in lockdown a lady phoned to ask if I could help to identify a plant from some photos. I recognised the odd-looking yellow-green umbellifers as perfoliate alexanders (spelled here with a low case A despite the name coming from the Egyptian port of Alexandria).
Perfoliate alexanders, Norwich, 25 April 2020 (Roger Jones)

Perfoliate alexanders is a flower I hadn’t seen in the form shown here, though it is similar to a flower I know from Crete. More of that later.

The photos had been taken by Roger Jones, and I know Roger & Jenny well. They live not far away and often come on the guided walks at NWT Thorpe Marshes, contributing their knowledge and enthusiasm there and, like me, on the NWT’s blog and elsewhere.

Roger had photographed the perfoliate alexanders near the River Wensum in central Norwich, not far from picturesque Pull’s Ferry. Armed with a name, he quickly tracked some other records by experience botanists in a national database. One of those noted that the plants had been removed. I expect that is because this species is classed as a potentially invasive alien. Perfoliate alexanders (Smyrnium perfoliatum) is on Schedule 9 part 2 of the Wildlife and Countryside Act 1981: plants that should not be allowed to be released into the wild. It’s there alongside better-known ‘baddies’ such as Himalayan balsam, Hottentot fig, giant hogweed and several water-weeds.

Rosa rugosa, NWT Thorpe Marshes, 17 June 2020.
Is there a risk? The best answer is ‘don’t know’. There are many escaped plants that are ‘occasional’ or fairly established that don’t really seem to matter, in terms of their ecological impact, and arguably add interest to life. However, in general, if it’s on Schedule 9, that’s for a reason and caution is called for. I saw a well-informed botanist mention that perfoliate alexanders is said to be a concern on some wildlife sites in London, and that it would be a pity to risk the same in the Broads.
I was interested to see that there are two plants from Schedule 9 part 2 that can be found on my local patch of the NWT Thorpe Marshes. Neither, yet anyway, are a problem. One is few-flowered leek Allium paradoxum, isolated plants on a bank. The second is Japanese rose Rosa rugosa, a single shrub on the riverbank. This rose can be invasive on coastal dunes.

Perfoliate alexanders, Norwich, 30 May 2020, well past its best.
As the name suggests, perfoliate alexanders is very closed related, the same genus, as (common) alexanders (Smyrnium olusatrum). Opinions vary on this plant: it is a distinctive feature of Norfolk roadside verges especially near the coast and it was a candidate for Norfolk’s county flower. Others might regard it as an invasive non-native, though as it is said to have been introduced from the Mediterranean by the Romans, it’s generally accepted as part of our flora now.

It took me far too long – where does the time go in lockdown? – to see my first perfoliate alexanders for myself, by which time it was past its best and the riverside park was uncomfortably busy on my weekend visit by bike.

The form of perfoliate alexanders from Crete is Smyrnium (perfoliatum) rotundifolium, meaning round-leaved. The brackets indicate that some consider it a subspecies of the flower I saw in Norwich. It’s more often treated as a different species, albeit the same English name. It makes a distinctive show along some roadsides north of Plakias and at the wonderful orchid-rich Kedros foothills, better known as ‘Spili Bumps’.

Perfoliate alexanders (rotundifolium) Crete, April 2017.


  1. thank you for identifying Allium paradoxum, the few flowered leek for me! We have it in the water meadows in Bury St Edmunds and I know it's invasive, but didn't know what it was.


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