From our perspective in the soil, the presence of Salvia officinalis, or common sage, is largely beneficial. Our roots exude certain biochemical compounds into the surrounding earth. For plants like rosemary, cabbage, and carrots, these exudates are stimulating. They can help improve our overall vitality and even enhance the flavor potency of our leaves and fruits. We grow more robustly when sage is nearby, as it helps create a soil environment that is to our mutual liking, particularly in terms of drainage and mineral availability.
Sage is a powerful guardian plant. Its strong, aromatic scent is a natural repellent for many common insect pests that would otherwise feast upon our more vulnerable leaves. This is particularly welcomed by us brassicas, such as broccoli, cauliflower, kale, and Brussels sprouts. The sage's scent effectively masks our own scent, confusing pests like the cabbage moth, making it harder for them to locate us. Furthermore, sage helps deter carrot flies from attacking carrot roots and can even help keep black flea beetles away from our colleagues in the nightshade family, like tomatoes.
While sage’s primary role is often as a protector, it also serves as a beacon. When sage produces its beautiful flowering spikes, it attracts a host of beneficial pollinators like bees and butterflies to the garden. This increased pollinator traffic benefits all flowering plants in the vicinity, ensuring better fruit set for plants like tomatoes, beans, and strawberries. Additionally, these blooms also attract predatory insects such as parasitic wasps and hoverflies, whose larvae are voracious consumers of common pests like aphids, offering us another layer of protection.
However, not all plant relationships are harmonious. It is crucial to note that sage can be antagonistic toward some species. We, the cucurbits like cucumbers and courgettes, find sage's growing conditions and its potent root exudates to be inhibiting to our growth. Similarly, sage tends to stunt the development of members of the Allium family, such as onions and garlic. The strong aromatic compounds and competitive nature of sage for soil resources create an environment where these plants struggle to thrive, leading to reduced bulb size and overall vigor.
