St. John’s Wort / Hierba de San Juan

St. John’s Wort (Hypericum perforatum) is the true medicinal St. John’s Wort, and it is a perfect example of why knowing the botanical name of a plant matters. There are hundreds of different Hypericum species, and many ornamental varieties are sold under the common name St. John’s Wort. Hypericum perforatum is the medicinal species. One of the easiest ways to recognize it is to hold a leaf up to the light. You will see tiny translucent dots throughout the leaf that look like little perforations, which is exactly where the name perforatum comes from.

It is a beautiful spreading plant with small green leaves and brilliant yellow flowers that seem to glow in the garden. Once established, it gradually works its way outward and can form a wonderful patch of flowering groundcover. The flowers are also excellent for attracting beneficial insects and pollinators, making it a valuable plant not only for the medicine garden but for the larger garden ecosystem as well.

St. John’s Wort is an important traditional herb for the nervous system. It is especially known for supporting mood, emotional balance, nervous tension and periods of sadness or heaviness, but I also value it tremendously for the physical nerves themselves. Traditionally it has been used for nerve pain, irritated or damaged nerves, wounds, bruising and injuries where the nervous tissue is involved. The flowering tops are generally harvested when the plant is in full bloom and can be made into tinctures, teas and infused oils. The beautiful red colour that develops in a good St. John’s Wort oil is one of the signatures of this plant.

It likes plenty of sun and well-drained soil and does not need especially rich conditions once established. Keep young plants consistently moist while they are developing their roots, but mature plants tolerate periods of dryness quite well. Depending on the climate, it can spread strongly through both roots and seed, while in hotter, drier conditions it may establish much more slowly. It is a perennial, so once it finds a place it likes, it can return and expand year after year.

I love St. John’s Wort because it combines so many things in one plant: bright flowers, medicine for the nervous system, a wonderful relationship with beneficial insects, and a spreading growth habit that helps keep the soil covered. Just make sure you are growing Hypericum perforatum, the true medicinal St. John’s Wort, and look for those tiny windows of light in the leaves.