Garden Myths – Ants will not walk over Pennyroyal

Ants are a particular nuisance in the garden – not because they do any harm to the plants themselves, but rather because they protect (and farm) a variety of other harmful pests, such as aphids, scales and white flies.

Stopping ants from climbing up your plants is a simple procedure: Ensure that the main stem or trunk is the only access point to the ants by clipping the plant away from walls and other places where ants can climb onto the plant. Then, apply a barrier on the trunk that the ants can’t cross. Horticultural glue is often recommended for this purpose, but after a long search, I couldn’t find a supplier in South Africa. Someone recommended I plant Pennyroyal around my tree trunks – Apparently, they said, the ants will not walk over the Pennyroyal. A further search on the net confirmed this, so hell, I’d give it a shot.

Even the label says it repels ants, so it must work, right?

Even the label says it repels ants, so it must work, right?


I decided on my lemon tree as a test – it suffers from all sorts of pests (as all citrus trees do!) and ants are regular tenants.

Pennyroyal planted around the tree trunk.

Pennyroyal planted around the tree trunk.


After planting, I had a close look at the tree. Sure enough, I spotted the pesky ants. I followed them closely as they walked down the trunk, crossing over onto the Pennyroyal leaves and walk over it like any other plant.


Garden Myth busted!

Other Garden Myths in this series:

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