Sunday, 9 December 2012

Lichen, moss and liverwort

Interesting Problems

      I once took my three children on holiday in Dumfriesshire. We were staying in a cottage about five miles into the hills from Dalbeattie. The idea was to have a week away from radio and television (computers didn’t loom large then) and spend time playing games, reading and actually talking to each other. My wife had booked the place but couldn’t come because she had to work. She said.

      It was ideal. The fact that water was hand-pumped from a bog at the bottom of a field led to some interesting wildlife studies over a cup of tea, and the creativity involved in advertising ‘Hot Shower’ as one of the amenities made the invention of television pale by comparison: the shower consisted of a Killaspray, which is a five litre plastic container with a pump handle and a length of hose attached to a spray nozzle. It is intended for killing pests. On this one, the nozzle had been replaced by a watering can rose. The idea was that you heated water on the Calor gas stove (there was no electricity), poured it into the container and held the watering can rose over your head, sweating as you pumped like hell. Water then trickled out at the rate of a two-year-old urinating, with the perplexing result that you were more in need of a shower after than you were before.
Lichen covered tree

      And in these sort of conditions we existed for a week. Perhaps more features of this holiday, which became annual, will be shared in future blogs but the point I want to make is that life forms can exist together under the most intimate and hardy of circumstances. Take lichens, for example. These can be seen in different forms growing on trees and rocks. Looking like a single plant, they actually consist of an alga, which has chlorophyll and can make its own energy-giving sugars, and a fungus, which is unable to do this. The fungus is, however, more able to take in and store water and mineral nutrients. These cohabitors then share the fruits of their labours so successfully that some species can live for hundreds of years.
Yellow lichen

      A question I’m often given is ‘is this stuff killing my tree?’, and the answer is no. In fact the presence of lichen indicates the clean atmosphere it needs to operate in, implying a healthy environment. Lichens don’t live happily with pollution and scientists use them as one pointer to the health of the atmosphere.

      Liverworts are sometimes mistaken for lichens, but  are structurally closer to mosses. Like mosses, they thrive in damp conditions and can be a problem where the gardener is an over-enthusiastic waterer.

      Another common question is ‘how do I get rid of moss in the borders?’ People resort to applying chemicals which kill it, only to find it rearing its head again fairly quickly, simply because they persist in leaving bare soil between their plants. Bare earth is like your loft: leave a space and it’ll get filled with something – not old Christmas decorations in this case, but moss or weeds. The simple answer therefore is to copy nature by planting to cover the soil. The same in the lawn – get the grass growing healthily and it will out-compete moss.
Moss growing on fence post.

      The second most useful piece of information I can give is to work as closely to nature as possible in the garden. The first is to hire a cottage with a proper shower.

Any questions about any of the above or other aspects of gardening? Put them under ‘comments’.







1 comment:

  1. Question - to insulate or not to insulate?
    I have a gunnera (probably manicata)and my late wife, from whom all of my gardenning knowledge sprouted, always insisted that we insulate the gunnera from frost with bracken. Is this necessary? I note from my recent trip to Ireland and this Department of Agriculture website that g tintoria is a very invasive plant in Ireland. This species thrives without insulation. What do you think?