Whether you garden in the ground, in raised beds, on the patio, or anywhere else, St. John's wort is a great addition or re-addition to your plant family. Read on for simple, straightforward specifics about growing St. John's wort.
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Family | Container Size | Good Companions | Bad Companions | Soil Conditions | Germination | Sun | Water | Temperature Range | Height | Lifespan | Reproduction | Yield Per Plant | Ingestibility | Further Reading
What Family Does St. John's Wort Belong To?
St. John's wort (Hypericum perforatum) belongs to the Hypericaceae family, also known as the St. John's wort family.
As the family name suggests, most of its relatives are other types of St. John's wort such as tutsan. The growing conditions and suggestions noted in this article apply to most members of this family, even though we are mostly focused on H. perforatum.
What Size Container Should I Use for Growing St. John's Wort?
The minimum container size recommended for St. John's wort is 5 gallons.
When grown in the ground, St. John's wort has a taproot of 2-5 feet in length, so plants grown in the ground tend to be larger and more vibrant. However, this tough plant can absolutely survive in a container if needed.
Learn more in our Choosing the Right Planter for Your Container Garden article here.
What Are Good Companion Plants for St. John's Wort?
Although it grows well with most plants, some of St. John's wort's best companions are as follows:
- Echinacea
- Aster
- Daisy
- Bee balm
- Geranium
- Marshmallow
- Lettuce
- Artichoke
- Stevia
- Watercress
- Hibiscus
- Wheat
- Barley
- Oat
- Sorghum
- Corn
- Lemongrass
- Spinach
- Quinoa
- Amaranth
- Orach
- Chard
- Beet
- Walnut
What Are Bad Companion Plants for St. John's Wort?
St. John's wort is not compatible with every plant. Some things to avoid planting with St. John's wort are as follows:
What Soil Conditions Does St. John's Wort Need?
St. John's wort prefers well-draining, moist soil.
However, it thrives in many conditions outside its ideal ones as well. For example, it can be drought-tolerant once established. It even grows in compacted and poor-quality soils. It is not particular about whether the soil is sand, loam, or clay.
How Long Does St. John's Wort Take to Germinate?
St. John's wort takes 10-25 days to germinate at a temperature of 60-75°F.
How Much Sun Does St. John's Wort Need?
St. John's wort can grow in full sun to part shade.
In other words, it grows fastest in full sun. It will still grow in dappled shade or part shade, just at a slower rate. St. John's wort grown in the shade will have fewer flowers than if it was in full sun.
Sun recommendations can vary by region, and St. John's wort grown in hot areas or in warmer conditions than the ideal temperature range noted below may need more shade.
How Much Water Does St. John's Wort Need?
St. John's wort needs 1 inch of water per week.
It does best when being watered deeply less often, rather than more frequent, shallow watering sessions.
What Is the Ideal Temperature Range for Growing St. John's Wort?
St. John's wort grows fastest in temperatures of 55-80°F.
This is its ideal temperature range. Although it will grow in temperatures both cooler and warmer than this range, the growth could be slower or even stunted.
Minimum and maximum temperatures will vary by variety. Some St. John's wort varieties are best for longer harvests and others for warmer climates.
How Tall Does St. John's Wort Get?
The average height of St. John's wort is 2-4 feet.
Is St. John's Wort Annual, Biennial, or Perennial?
St. John's wort is a perennial herb, meaning that it lives for longer than a couple years. Specifically, it lives for about 3-5 years on average.
How Does St. John's Wort Reproduce?
St. John's wort reproduces by seed. It can produce up to 100,000 seeds per year.
How Much St. John's Wort is Produced Per Plant?
For St. John's wort, how much is produced per plant (also called the yield) depends on the size of the plant.
Most St. John's wort plants produce 20 flowers per stem per year. Since the plant grows larger each year, it produces more total flowers each year.
Can St. John's Wort Be Ingested?
St. John's wort flowers and leaves are edible.
St. John's wort flowers have antispasmodic and nervine properties and can be used in herbal preparations. The most common preparations are tea and tinctures.
An herb:solvent weight ratio of 1:2 at 95% alcohol is suggested for a fresh St. John's wort flower tincture. An herb:solvent weight ratio of 1:5 at 40% alcohol is suggested for a dried St. John's wort flower tincture.
The properties of this plant are best preserved when it is tinctured (or made into herbal oil or tea) using fresh or slightly wilted flowers rather than dried ones. This is different from most herbs, for which it does not matter whether they are fresh or dried. However, some of the most powerful constituents of St. John's wort are dramatically reduced by the drying process.
St. John's wort is contraindicated with some medications, so check with your doctor before ingesting it if you are on any long-term medications. It can also intensify light sensitivity if taken in large doses. There are no other known safety concerns associated with ingesting St. John's wort flowers or leaves for the general public. See our Using Herbs article here for more information.
See this article for more information about ingestibility in general. See the simple uses article linked below for examples of ways to prepare this specific plant.
Further Reading
This article is intended as a quick-reference guide for gardeners. Consult your seed packet or seed catalog for variety-specific information.
When you have a bumper crop of St. John's wort rolling in, you may not have enough time for long, complicated recipes or many-step preservation procedures. Check out my article on quick, simple uses for St. John's wort here!
St. John's wort is featured in these Plant to Plate articles:
- Simple Uses for St. John's Wort
- Gardening in Full Sun
- Gardening in Dappled Shade
- Gardening in Part Shade