St. Johnswort (Hypericum): A Complex Genus for the Curious Gardener
If you’ve ever wondered about planting St. Johnswort in your garden, you’re not alone! But here’s where things get a bit tricky – Hypericum isn’t just one plant, it’s actually a massive genus containing hundreds of different species. Think of it like asking Should I plant a rose? when there are thousands of rose varieties, each with their own personality.
What Exactly Is Hypericum?
Hypericum, commonly known as St. Johnswort, represents a diverse group of plants that can be annuals, biennials, or perennials. These plants are classified as forbs or herbs – essentially, they’re vascular plants without significant woody tissue above or at ground level. What this means in plain English is that they’re not shrubs or trees, but rather herbaceous plants that may die back to the ground each year or persist as low-growing perennials.
Where Does Hypericum Grow?
Here’s where the plot thickens! Hypericum species have made themselves at home across an incredibly wide range, including Alberta, Alabama, British Columbia, Manitoba, New Brunswick, Arizona, Arkansas, California, Nova Scotia, Ontario, Colorado, Prince Edward Island, Connecticut, Quebec, Delaware, Saskatchewan, District of Columbia, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming, Puerto Rico, and Newfoundland.
The Native Status Puzzle
Now here’s where things get really interesting (and a bit confusing). The native status of Hypericum varies dramatically depending on where you are:
- In Hawaii, Hypericum species are considered non-native plants that have been introduced and now reproduce on their own in the wild
- In Puerto Rico, Hypericum is considered native
- For Canada and the lower 48 states, the status is undefined
This complexity exists because we’re talking about an entire genus rather than a specific species. Some Hypericum species are native to North America, while others were introduced from Europe, Asia, or other continents.
Should You Plant Hypericum?
The honest answer is: it depends entirely on which specific species you’re considering and where you live. Since the invasive and noxious status of Hypericum as a genus is unknown, and different species have vastly different behaviors, here’s what we recommend:
- Research the specific Hypericum species you’re interested in, not just the genus
- Check with your local native plant society or extension office about which species are appropriate for your area
- If you’re passionate about native gardening, focus on species that are confirmed native to your specific region
- Consider native alternatives that provide similar benefits if you’re unsure about a particular Hypericum species
General Growing Tips
While growing requirements vary significantly among Hypericum species, many share some common preferences. Most appreciate well-drained soil and can tolerate a range of light conditions from full sun to partial shade. They’re generally low-maintenance plants once established, but specific care requirements depend entirely on which species you choose.
The Bottom Line
Hypericum represents a perfect example of why botanical names matter in gardening. When someone says St. Johnswort, they could be referring to any number of very different plants with varying growth habits, native status, and garden suitability. Before adding any Hypericum to your garden, take the time to identify the exact species and research its behavior in your specific region.
Remember, responsible gardening means knowing not just what you’re planting, but how it might affect your local ecosystem. When in doubt, consult local experts who can guide you toward the best choices for your garden and your region’s native plant communities.
