Alexanders

Alexanders (Smyrnium olusatrum)

When it comes to invasive species that try hard to take over the garden, there are few things that beat Alexanders (Smyrnium olusatrum). Native to the Mediterranean region, it was brought to the UK by the Romans, back when the islands were still part of the vast Roman Empire. Presumably because of where it evolved, it's sensitive to frosts, and is most common along the UK's coastlines, where frosts are less frequent. It currently smothers roadsides and cliff edges across much of Wales, southern England and eastern Ireland.

Alexanders are vigorous biennials. In the first year, they send up a spray of leaves about a foot high. The second year is when they really come into their own, shooting up to 5-feet tall or more. Covered by scores of umbellate flowers (many branches coming from the same point, like an umbrella), they are a major draw for pollinators from March to June. Many of our early-season insect photos are taken on their flowerheads. The plants are incredibly hard to get rid of; their roots are strong and deep, with a taproot that looks like a particularly fat parsnip. We've found that leaving them until the plant has gone to seed helps, as the root starts to shrink then. But then we have to be sure to grub them out before their thousands of jet-black seeds drop off !

Alexanders is a relative of celery, and was widely used in cooking as recently as the 1700s. It's said to taste either like a cross between celery and parsley or like angelica. All parts of the plant are edible. Though used in the past to treat wounds, asthma and menstrual problems, it is no longer considered to be a medicinal plant. Much as we struggle to control it, we'll probably continue to allow a few to flourish each year — just to provide something for all those early-season insects to eat.

The umbellate flowers of Alexanders