Answers to Your Questions: What to Do About L Liverwort

I am having trouble getting rid of liverwort in my flower beds. Despite my efforts to remove it, it keeps growing back and spreading everywhere. How can I get rid of it effectively?

Answer

To learn how to eliminate liverwort (Marchantia polymorpha) from fountains, you first need to understand how it grows.

It is a perennial plant native to Canada that belongs to the bryophytes, a group that includes mosses, liverworts, and hornworts. It is therefore a non-vascular plant: it has no vessels to transport water and nutrients within its body. It absorbs them directly through its tissues.

It also has no roots, but rather small filaments called rhizoids, which mainly serve to anchor it to surfaces. Since it cannot draw water from the soil, it depends heavily on ambient humidity to survive and multiply.

The liverwort mainly spreads through thallus fragments. The thallus is a flat, thin, green part that resembles a leaf, but does all the work of the plant: absorbing water and minerals, breathing, and photosynthesizing. It also spreads through tiny “cuttings” called gemmae, which rain carries a short distance away to form new plants, and more rarely through spores.

Conditions favorable to invasion

Liverwort infestations are common in commercial production, especially in greenhouses, where watering and fertilization are regular. Since liverwort depends on moisture and nutrients present on the surface rather than deep in the soil, these conditions provide an ideal environment for it to grow rapidly on potting soil.

I don’t know the conditions in your garden, but I’m going to assume that the soil often stays moist, either naturally or because it is frequently watered. There’s also a good chance that the area is in shade or partial shade—the preferred environment for liverwort—which helps to retain moisture. The use of fertilizers, especially liquid fertilizers that are rich in nitrogen and applied often, mainly feeds the surface of the soil and thus promotes its spread. It’s also possible that the soil is compact, which prevents water from draining properly, and that the soil surface is bare. In short, these are exactly the conditions that liverwort loves and that can lead to an infestation.

Combating infestation

First and foremost, liverwort is not the cause of the problem, it is a symptom. To reduce or eliminate liverwort from your garden, there is no magic solution or product to buy, you just need to change the conditions that favor its growth. To start with, you will probably need to reduce the amount of water in the soil. If you water a lot or have an irrigation system, simply reduce the frequency. If the soil is naturally moist or poorly drained, you will need to correct this by improving its drainage, for example by creating a slight slope to help water run off, installing a drain, or adding organic matter such as compost. Compost improves soil structure, making it more well-drained and aerated in the long term, which allows water to infiltrate better and prevents it from stagnating on the surface.

Weeding alone will not solve the problem if conditions do not change. Once the causes have been identified and corrected, pull up the liverwort by removing entire patches to avoid fragmenting it, as each piece can come back to life. Also avoid composting it unless you have a hot compost bin. Fortunately, since it has no real roots, it is easy to pull up.

To prevent it from returning, apply a 5 to 10 cm (2 to 4 inches) layer of organic mulch—shredded leaves, chopped branches, straw, etc. Mulch blocks light from young shoots, keeps the surface drier, and retains moisture deeper in the soil, which discourages liverwort while helping your other plants grow better.

The alternative

The alternative to all this is simply to accept its presence. Unlike in a commercial production environment, where it can interfere with watering and nutrition for potted plants, in a garden, its impact is generally inconsequential for other plants. If some of your plants seem to be suffering, it may be because they are not well suited to the type of soil, humidity, or amount of sunlight in that location.

If you plant enough vegetation, close enough together that their foliage touches just a little, you won’t even see the ground where the liverwort is. It will disappear on its own or remain hidden under a carpet of greenery. After all, you don’t tame nature, you learn to live with it.