Every Wednesday, I hope to find a new ‘weed’ to investigate. My only criterion will be that I will not have deliberately planted the subject of our inquiry. Who knows what we will find…..
When I was doing my exploration of St Pancras and Islington Cemetery last week, I came across this delicate-looking, lilac-flowered plant. For all its seeming fragility, it was doing a great job of scrambling across the brambles and the bindweed. When looked at closely, it’s easy to see that this is a member of the pea family – the anchor-shaped hooks at the end of each frond of leaves are used to attach to whatever happens to be close by, and later in the year the plant will develop pods, each containing tiny ‘peas’.
Like all peas, Tufted Vetch fixes nitrogen in the soil. It does this because its roots contain nodules in which a bacteria called Rhizobia lives. While the plant is alive, the bacteria produces nitrogen compounds which help it to grow, and to compete with other plants. When the plant dies, the nitrogen is released, making it available to other plants and hence helping to fertilise the soil. As nitrogen is one of the building blocks for DNA and for proteins, this is vital to the health of the whole ecosystem.
Another name for Tufted Vetch is Cow Vetch, because it has been widely used as forage for cattle. Like all members of the pea family, it is also a great favourite with bees. The plant is native to Europe and Asia, but has been introduced to North America, where in areas of prairie it can be more vigorous than the native plants, crowding them out, and is therefore sometimes viewed as a detrimental weed. I find this a little surprising – although it is a scrambler, Tufted Vetch doesn’t seem much of a thug, certainly not when compared to plants like Bindweed.
The true beauty of Tufted Vetch is seen when it’s growing in a tangle with Birdsfoot Trefoil and Clover, bedstraws and buttercups. The gardener and cook Sarah Raven, in her book ‘Wild Flowers’, says that:
‘I often think I would love to cut one of these combinations with a single swipe of a sickle and put it all in a vase’.
I know what she means, but how much nicer lay on your back in a meadow, look at the tangle of flowers and watch the ladybirds and butterflies going about their business.