From our perspective, our mint roots release potent biochemical agents into the soil, a strategy known as allelopathy. These substances, primarily menthol, are our primary defense mechanism. They effectively suppress the germination of seeds and impede the root development of nearby plants that we perceive as competitors for precious resources like water and nutrients. This is not a malicious act but an evolutionary survival tactic to secure our territory and ensure our colony thrives. Therefore, our very nature dictates that we are not compatible with all plants.
Certain plants have evolved a tolerance or even a beneficial relationship with our aggressive chemistry. Members of the Brassica family, such as cabbage, kale, and broccoli, appreciate our presence. Our strong scent acts as a powerful aromatic camouflage, effectively masking their smell to confuse and deter common pests like cabbage moths and flea beetles. Furthermore, our flowers are highly attractive to predatory insects like hoverflies and parasitic wasps, which will also patrol your brassicas, consuming aphids and caterpillars.
Conversely, many plants suffer greatly when forced to share soil with us. Herbs that require dry, poor soil conditions, such as chamomile and lavender, will be overwhelmed by our vigorous, moisture-loving growth habit and our soil chemistry. Most notably, we are profoundly antagonistic to members of the Lamiaceae family, our own cousins. This includes sage, rosemary, basil, and thyme. Our allelopathic compounds directly inhibit their root systems and overall growth, leading to stunted, weak plants. It is crucial to keep us separate from these herbs.
Our most defining characteristic is our relentless, spreading rhizome system. We do not recognize garden borders; we seek to expand and colonize. To coexist with us in a polyculture, you must respect our nature by physically containing us. Planting us directly into the ground, even near compatible companions, will inevitably lead to us dominating the entire space. The only successful strategy for companion planting is to sink us into the garden bed while still potted, with the pot's rim above the soil line. This allows our foliage to provide benefits while our roots are restrained, protecting both allies and foes from our invasive tendencies.
