March 2018

I have heard that grass doesn’t grow when the soil temperature is below 6 degrees C.  It is quite irritating then to find that despite the cold and dull weather that seems to have persisted for weeks, that our lawn needs mowing.  It’s even more irritating that it’s too cold and wet to get out there for the first mow of spring.  Grass is always a chore for gardeners, if it’s in the border it needs weeding out, if it’s not it probably needs mowing.

Unidentified, possibly Sweet Vernal Grass

It may however, be worth pausing as you empty the grass box, to marvel at one of nature’s most successful plants.  It grows just about everywhere from the high tide mark to well above the treeline and from the tropical rain forests to all but the driest deserts.  It comes in many forms – as grasses, sedges, and rushes, and even bamboo.  Incidentally, grasses, sedges and rushes are in separate families – Poaceae, Cyperacae, and Juncaceae respectively – and if you are not sure which is which then you need to remember the rhyme, ‘sedges have edges, rushes are round and grass stems are hollow right up from the ground’.  (That refers to the flowering stems which are triangular in the case of sedges.)  If you choose a grass species with fat seeds and fill a field with it, then you will have part of the world’s staple diet.  Where would we be without wheat or rice, or my own particular favourite, barley? (roasted and suitably mixed with another favourite native plant species Humulus lupulus, better known as the common hop.)  Another large part of our diet (too large in many cases) is derived from yet another grass – sugar cane.

Canary Grass

There are more than 10,000 different species of grass worldwide, and it is likely that your garden, however tidy you keep it, will contain a dozen or more different ones.  Identification of grasses is not easy and requires a lot of time looking for identifying features and following keys.  The botanical language used is different to that used for other plants because grasses have things like awns and stipules and spikelets that other plants don’t have.  Of course, the first thing you need to do to identify any type of grass is to stop mowing it and let it flower.  Grasses are wind pollinated and so they don’t need showy scented flowers to attract insects.  This means that the flower features are quite small and a hand lens is useful to see them clearly.  I have managed to identify a few species in our garden – Sweet vernal grass, which gives new mown hay its sweet smell, Quaking grass, Cock’s Foot, Field Wood-rush (a small but pretty species), Perennial Rye grass, and of course Common Couch grass.  Yet another species that I am trying to eradicate is Pendulous Sedge – if you have any, I recommend that you don’t let it flower!

Unidentified, possibly one of the False Oats

I find that the names of grasses have a sort of ancient and romantic feel to them.  Things like bents and fescues, crested dog’s tail, wood melick and canary-grass.  Believe it or not, there’s even one called Timothy.

Field Wood-rush