How to Grow and Care for St. John's Wort

St. John's wort, also known as goatweed or Klamath weed, is an herbaceous, perennial shrub with dainty yellow flowers that grows in many conditions, making it a popular choice. The plant prefers full sun but tolerates partial sun, can prosper in soils of all types and most pH levels, and can survive winters in regions as cold as USDA zone 3.

When planting, consider that St. John's wort can be toxic to people and pets.

St. John's Wort Care

St. John's wort is simple to grow and tolerant of a number of challenging conditions. Here are the main care requirements for St. John's wort:

• Choose a sunny location, ideally getting six hours of sunlight or more.
• Prepare moist but well-draining soil.
• Water regularly as the plant is first becoming established, though it will eventually be able to handle some drought.
• Fertilize lightly each year in spring.

Light

Growing St. John's wort in full sun in the North is ideal for best flower production. In the South, however, the plant profits from having a bit of shade.

Soil

Although the plant prefers a well-drained soil, it will survive somewhat compacted ground. St John's wort will also grow in acidic, neutral, or alkaline soils.

Water

Keep this perennial well-irrigated when you are first trying to establish it. Once mature, it is reasonably drought-tolerant.

Fertilizer

St. John's wort performs best in fertile soils, although it tolerates poor soils. Amend its soil with compost annually for best results.

Types of St. John's Wort

H. perforatum is not the only member of its genus for ornamental use in the landscape. The Hypericum genus has cultivars and shrubby species that some find even more eye-catching, including:

• Hypericum x inodorum 'Elstead,' which is perennial to zones 6 to 9 and has red berries.
• Hypericum x moserianum 'Tricolor,' which is also perennial in zones 6 to 9, has a slightly greater spread, and has variegated leaves.

Pruning

Because St. John's wort is such an aggressive spreader, pruning it in early spring is ideal. Cut back about one third of the entire plant, and remove any dead branches. This is also a great time to pull up any unwanted nearby St. John's wort plants that have sprung up on their own.

Propagating St. John's Wort

St. John's wort will spread easily on its own, but if you want to propagate it yourself, stem cuttings are a tried and true method. Here's how:

1. Use clean scissors or pruning sheers to take a stem cutting that's about 6 inches long.
2. Remove any lower leaves on the cutting.
3. Leave the cutting alone for a few days, allowing the "wound" at the end to heal.
4. Optionally, dip the cutting in rooting hormone to speed up the process.
5. Directly plant the cutting where you want the plant to grow.
6. Keep the soil moist until you can lightly tug on the cutting and feel that it has rooted.

How to Grow St. John's Wort From Seed

St. John's wort is also easy to start from seed. Here are the steps:

1. Lightly sprinkle seeds over the soil, and just barely press them in. Do not bury the seeds.
2. Spray or mist the soil, and keep it moist until germination.
3. Once the seedlings emerge, move them outdoors into the light right away, if they are not already outside or under strong grow lights.
4. Seedlings can be transplanted into their permanent spots once they are a few inches tall.

Potting and Repotting St. John's Wort

Growing St. John's wort in a pot is a good way to prevent it from spreading via rhizomes or creeping stems. That said, it grows so quickly that it will likely need to be repotted often, possibly annually. The best time to repot is before or after its growing season, in early spring or early fall.

Choose a pot that is one to two sizes bigger than the current pot. The type of container does not matter, as long as it has excellent drainage. Choose well-draining potting soil as well.

Common Pests and Plant Diseases

St. John's wort doesn't suffer from any known pests or diseases. It may be affected by wilt or root rot in very humid or wet conditions.

How to Get St. John's Wort to Bloom

St. John's wort should bloom year after year without issue, offering small yellow flowers with a somewhat odd smell.

Bloom Months

St. John's wort blooms in the summer and early fall, usually starting in June and flowering until September.

What Do St. John's Wort Flowers Look and Smell Like

The flowers on St. John's wort plants are small and numerous with bright yellow petals. They emit a slight, turpentine-like fragrance.

How to Encourage More Blooms

To get the most flowers out of your St. John's wort plant, make sure it's getting as much sunlight as possible, keep the soil moist, and feed the plant with fertilizer each spring.