Like insects, grasses, sprouted tree seeds, wildflowers, moss, lichens and other intruders will grow in our pots. It’s inevitable. Weeds are something we don’t talk about enough and totally wish I knew more about all the scandalous weeds to avoid! I will try to hash out some thoughts and guidelines as well as point out a couple of bad ones I’ve encountered.

Moss as top dressing is a great thing. It’s aesthetically pleasing and it adds many technical functions. It can be equally pretty when a variety of little plants start to pop up and add to a more natural looking, wild landscape. It can also get quite bushy and start to hurt the aesthetic of the tree. When my teacher was an apprentice she had a tree with a lot of wild growth in the pot that she enjoyed. Her teacher commented “It’s time to cut the salad!”

Many of these weeds however are not good for our trees. How do we know what is good salad and what is bad salad ? With so much variety even from garden to garden it will take some time to learn what can stay in the pot.

Firstly, if it is a tree seedling I will remove it straight away, maybe even put it in a little pot. As for “weeds”, the deciding factors come down to a very simple question:

  • Will the weed take valuable resources and compete with the tree?

Weeds can suck up precious nutrients , they can move a ton of water and they can grow physically large roots that compete for space, water and nutrients. They can even smother and kill some of the roots of the tree.

The weed pictured above looks innocent enough from afar.

When pulled, we discover it’s taproot is extremely thick and long. Imagine if left unattended! It would not only occupy valuable physical real estate in the pot , it would be taking water and resources at a rapid rate based on its size and rate of growth.

This root was a dandelion left unattended too long. Remove all dandelion!

This is liverwort and one that was a little less obvious to me. The root system is not large at all. At first I thought it was cool looking and added variety to the ground cover. I learned quickly by speaking to my teacher that this is very bad. A huge resource hog, invasive and it can weaken trees if unattended. It’s to be pulled and removed from the garden area entirely.

Lichens, as seen on this trunk do not hurt the trees. Like moss, they can grow on the soil surface as well as the bark of trees. In fact they add a nice impression of old age. Lichens are very hard to get to grow in the pots or on trees and it is a treat when they pop up.

Obligatory Semi-redundant recap

  • Remove tree seedlings
  • Remove weeds with large root structures
  • Pull weeds from as low down their base as possible to remove all of the root system.
  • Learn the weeds growing in your garden by gently pulling up the roots and determining what is too physically invasive.
  • Bring photos or samples to your teacher, local nurseries or horticulture centres and online to research more thoroughly.
  • Always a safe bet to simply remove all unexpected growth
  • Liverwort growth is a sign of overwatering (Thanks Rafael Najmanovich from the PBC for this tip!)

We need an ongoing discussion of which weeds are good and bad. Comment / share with your experiences and knowledge of your salads!

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