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…..
Dear Readers, I am sometimes astonished at the plants that crop up in East Finchley. Where do they come from? How did they get here? One particular ‘weed’ hotspot is a little bed outside the corner house on Park Hall Road. One month it’s full of cleavers, the next it’s full of thistles, and this week, it’s full of lucerne. And very pretty it is too, in its many shades of lilac and purple.
Lucerne is a member of the Fabaceae family, which includes peas, vetches and clovers, and if you look at the flowers you can see the characteristic lower ‘lip’. The leaves are in groups of three, but the most characteristic feature is the tightly-curled seedpod, which spirals around itself like one of those wacky Carsten Holler helter-skelters that were at Tate Modern a few years ago. The name ‘lucerne’ is said to have come from the Latin ‘lucerna’ or lamp, which makes me wonder if there were oil lamps that resembled the shape of the seedpod.
Lucerne was introduced to the UK in the 17th century as a fodder crop, and is otherwise known as alfalfa (which is from the Arabic name for the plant). It probably came from south west Asia, and was first noted in the wild in the UK in 1804. The plant was first cultivated in ancient Iran, and in a fourth-century book about agriculture, Palladius notes that it can be cut four to six times in 12 months, and that a quarter of a hectare of lucerne will feed three horses for a whole year. Palladius also notes that fresh lucerne should be fed sparingly to cattle, who may develop bloat, and indeed domestic animals have a paradoxical relationship with the plant, sometimes developing photosensitivity and jaundice. However, it is a major source of hay and silage for cows and horses, particularly in North America, where in Arizona and Southern California a single field can be cut up to twelve times in a year.
It has never been much used for human food in the West, with most people encountering it as alfalfa sprouts. It was used as famine food during the Spanish Civil War, but in China the young leaves are used as a salad vegetable.Incidentally, anyone getting excited at the plants’ Latin species name (sativa) should note that, although lucerne was used unsuccessfully as an ingredient in cigarettes, ‘sativa’ simply means ‘cultivated’.
Like most members of the pea family, lucerne is a magnet for bees. There is a story that lucerne could not be grown commercially in the US until the honeybee was introduced to the country (it is not native north of Mexico), and pollination became possible. It is often the case that introduced plants do not become a problem if their pollinators do not arrive – Dave Goulson, who wrote the wonderful book ‘A Sting in the Tale’ describes how Tree Lupins only became problematic in Australia once the bumblebee arrived. I always find it interesting how these complex webs of life change when one of the elements is missing.
Indeed, there is a problem with the pollination of lucerne. When Western honeybees visit a lucerne flower, they are knocked on the head by the keel of the plant, which transfers the pollen. Neither you nor I would like to be hit on the head every time we went to work (though I’ve been employed at places where every day felt a bit like that was what was happening). So, the honeybees take to nectar-robbing – piercing the side of the flower to get at the nectar store without being walloped. Unfortunately this does not result in the pollination of the plant.
To avoid this happening, the beekeepers employed to pollinate the lucerne fields use a high proportion of young, innocent bees, who have not yet become jaundiced and cynical by their daily experiences. However, young bees are also not as expert at performing their tasks. Also, the bees quickly suffer from a protein deficiency induced by only eating lucerne pollen, which is missing one of the key amino acids.
One answer is to use alfalfa leafcutter bees (Megachile rotundata) to do the pollination. These solitary bees, native to Europe, produce no honey, but are very efficient pollinators of lucerne. They are transported in hollow plastic tubes, which they fill with leaves and use to raise their young. These are the bees of choice in the Pacific Northwest, with the poor old long-suffering honeybee being used in California.
In parts of the US lucerne is used as an insectary, a nursery for all kinds of predatory insects, and is often interspersed with cotton. The various ladybirds and lacewings and wasps that hatch in the lucerne go to work on the grubs that would otherwise eat the cotton. In return, the lucerne is harvested in strips to avoid killing the entire insect population.
Lucerne is a very drought-hardy plant -it has a root-system that can penetrate almost 50 feet to find ground-water. It can live for more than twenty years, but the plant is autotoxic – lucerne seeds cannot grow where there is already lucerne, and so crop rotation needs to be practiced. Like all members of the pea family, the roots contain nitrogen-fixing bacteria, which means that it improves the soil. As such, it was the most widely grown fodder crop in the world in the early 2000’s, with over 436 million tons grown, not just in North America but in China, Russia, Europe and Argentina. In 2009 over 74 million acres of the planet were used to grow lucerne. Not satisfied with this, the biotech giant Monsanto developed a GMO version of the plant that was resistant to glyptosate. This meant that fields could be sprayed with Round Up, which would obliterate all the ‘weeds’ but spare the lucerne. There has been a long-running court case in the US about the use of this plant, with many concerns about the possibility of cross-contamination with non-GMO lucerne. You can read all the gory details here, but suffice to say that Monsanto appears to have won, as usual. Whilst here in Europe we tend to be cautious about GMOs, there are far fewer restrictions in the US. I shall watch with interest to see how this all plays out. I am not anti-science, but it seems to me that obliterating biodiversity in this way runs counter to the health of the environment. I sometimes wonder at what point we will stop messing with delicately poised ecosystems. As the Buddha once said, we are children playing in a burning building.
So, generations of domestic animals have been fed on this delicate ‘weed’ that has appeared, surprisingly, on a London street. And when I go hunting for a poem about lucerne, I find this by Les Murray, the extraordinary Australian poet. ‘The Cows on Killing Day’ is not an easy read, but I don’t think I have ever read a poem that imagines so sensitively what it would be like to be an animal. Have a look, and let me know what you think!
Photo One (Lucerne Seedpods) – By Philmarin (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
Photo Two (Carsten Holler Slides) – Kirsteen at https://www.flickr.com/photos/commonorgarden/300219278
Photo Three (Alfalfa sprouts) – By Thesupermat (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
Photo Four (Honeybee on lucerne) – By Ivar Leidus – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=50280387
Photo Five (Leafcutter bee on lucerne) – By Pollinator at en.wikipedia, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=16375247