You can get it free at most garden centres – and there are not too many plants of which that can be said.
You have only to purchase an outdoor plant in a pot … a plant which has is not exactly the latest addition to the stock … and there it all-too-often is. A seemingly-innocuous little mat of tiny, green whorls of vegetation doing no more than resting on the surface of the somewhat-compacted soil. Waxy, not-unattractive and seemingly-easily removed should one wish to do so, this is one of the plagues of contemporary horticulture. This is liverwort.
I have already written of the liverwort which has appeared in my garden, describing several of the methods I have used in my bids to rid myself of this insidious weed; and weed it most assuredly is in my garden …a plant persistently growing where I assuredly do not want it to grow. So ‘weed’ I shall call it, despite the fact that I am aware that it is possible to buy a number of species of liverwort from specialist nurseries, just as I am well aware that most garden centres sell Digitalis which, dear reader, you and I probably know better under its common name of foxglove. Foxgloves thrive on the side of the railway behind my home; foxgloves produce lots of seed, some of which finds its way into my ground; so Digitalis is a weed to me, growing uninvited in my garden wherever its seed can settle and germinate. But foxgloves are not difficult to pull out if they are spotted while they are still small plants. Liverwort is proving much more resistant to my efforts to get rid of it. So what is this pest and what other methods might I try to eradicate it?
Liverworts … and there are nearly 300 individual species of these plants … belong to a family called the Bryophytes. The most common in the United Kingdom is Marchantia polymorpha, a primitive form of plant life which fossil evidence suggests has been around for the better part of 500 million years. It has no roots and no system, as most plants have, to draw water from the ground and distribute it through the whole plant, although it does have tiny, root-like hairs which fasten the little plants to the ground and allow them to ingest moisture. Its waxy surface is fairly effective in retaining moisture within its tissue: but a prolonged spell of dry weather … I wish! … will cause the plant to dry up and shrivel, apparently dying of drought.
Alas, 50 million years of existence destroy any wild hope that this situation might result in the plant’s leaving this mortal coil. Liverworts disperse spores and gemmae … plant cells which detach themselves from their parent and form new plants … which are distributed by wind, water, or any other convenient means and which form a new colony wherever they land in a favourable spot. Poor soil, badly-drained soil, compacted soil and soil whose nutrients have been exhausted … like soil in a pot which has held a plant for too long … are just right. Bingo! The liverwort establishes a colony in less time than it takes to tell.
Right now, I am using a mulch of bark to smother the liverwort growing alongside my garden on the compacted, other-weed-eradicated soil which edges a local authority grassed area; I have treated the liverwort in the spaces between the paving slabs on my patio with a glyphosate-based weedkiller to which I have added a small quantity of detergent to overcome the plant’s waxy surface; and I have sprayed a small patch of liverwort which has appeared in a gravel path with a mixture of cheap, malt vinegar and detergent. If you choose to try either of the latter two methods, remember that vinegar is acetic acid, which is harmful to almost all plants, and that glyphosate kills most plant life, so take care. And the best of luck!