Foraging St. John’s Wort: How To Identify And Harvest
St. John’s Wort (Hypericum perforatum) is a common weed with beautiful yellow flowers that are well loved by pollinators and herbalists alike!
Learn how to identify and when to harvest this herb – then check out our accompanying article for information on making St. John’s Wort infused oil and salve for aches and pains!
Tips to Identify St. John’s Wort
St. John’s Wort is a sprawling plant that grows between 1 to 3 feet and tends to spread over a place (by rhizomes and by seed) – if you see one patch of St. John’s Wort, you’re likely to see another clump growing nearby!
It’s usually growing along roadsides or the edges of fields, or places where the soil has been disturbed. It usually likes full sun, but we’ve found a few clumps in partial shade too.
Flower ID + Pigment
The bright yellow flowers have five petals and lots of little yellow stamens, and if you look closely, you’ll see little black dots or spots on the edges of the petals.
One notable characteristic about the flowers is that if you crush a flower bud between your fingers, a dark red pigment will release, staining your fingers. For herbalists, this pigment means that the plant has active medicinal constituents.
The Leaves – Look for Pin Dots!
Another characteristic is the oblong leaves, which grow opposite from each other, over branching stems. If you hold a St. John’s wort leaf to the light, it will look like it has little pin dots all over it.
When to Harvest St. John’s Wort
Depending on where you live, St. John’s Wort blooms around June to August, often peaking in late June around the summer equinox (June 21-ish).
The summer equinox is also the traditional time for making tinctures and infused oils. However, if you’re in a different growing zone, you may find your St. John’s wort isn’t blooming then – that’s okay!
You can pick the flowering tops any time they are in bloom, though older flowers tend to have weaker amounts of the beneficial components. (To test this – crush a few flowers between your fingers. If they get pigmented red, then you should be good to collect!)
St. John’s wort is one herb that’s best used fresh – so don’t collect flower tops unless you have a plan to use them right after.
Usual foraging rules apply to St. John’s Wort – don’t harvest from roadsides or other sprayed areas. It’s considered an invasive or noxious weed in many states (and other parts of the world), so can be generously harvested if you live where there is abundance.
Can you grow St. John’s wort (Hypericum perforatum) at home?
Yes, you can, but be aware that it is considered an invasive plant in many places, where it has spread to the point of crowding out native plants.
We’ve had a patch of St. John’s wort growing in our gardens for over a decade and it has only spread slightly outside of the garden bed area. (In fact, the catnip and lemon balm are much more aggressive in that same area!) While it hasn’t become invasive where we live, it does have the potential, so take care to monitor and control the plant if you choose to grow it at home.
Also note that large amounts of St. John’s wort is toxic to livestock, causing photosensitization, loss of appetite, convulsions, and more.
Look Alikes for St. John’s Wort
There are 490 species of Hypericum – and some are native to the US, so if you don’t have Hypericum perforatum where you live, you may still spot a close relative growing nearby that looks similar.
Hypericum Online – a site devoted to Hypericum spp. and maintained by scientists and researchers – has a helpful list of those species, many with photos.
Even though there are so many other species of Hypericum, mainly Hypericum perforatum (what we commonly call St. John’s wort) has been studied and used extensively for natural medicine. However, a study from 2013 identified several other species that may have similar properties. Try crushing a few flowers and see if the red (reddish purple) pigment stains your fingers. If so, it’s possible (though not certain) that variety can be interchanged for external use.
How to Preserve St. John’s Wort
Fresh St. John’s wort can be immediately turned into:
- tincture (we use the folk method of 1 part fresh chopped flower to 2 parts 100 proof vodka)
- and/or infused oil, which can be turned into salves or creams. (directions in our next article)
You can also dry St. John’s wort flowers or flowering tops to use for tea. According to esteemed herbalist, Richo Cech, it’s also fine to use dried St. John’s wort to make tincture if fresh isn’t available.
Another way we use dried St. John’s wort is to make a liniment for sore muscles and varicose veins.
To dry St. John’s Wort
Gather the top 1/3 of the plant when it’s in flower. This includes flowers, buds, stems, and leaves. Alternatively, you may wish to just collect the opened flowers and buds.
Spread the herb out in a single layer on a drying screen or paper towels or dish towels and allow to air dry for several days to a week, or until completely dry.
Once the herb is totally dry, you can store it in a brown paper bag or a glass jar out of direct sunlight or indoor light. Shelf life is around 9 months to a year, or as long as the herb has a nice color and scent. If it fades to a drab brown color, then it has lost its benefits and should be composted.
How is St. John’s Wort Used?
When taken internally as a tea or tincture, St. John’s wort has traditionally been used to treat things like mild depression or seasonal affective disorder. (Though NOT for anyone on prescription meds.)
However, it’s also a great herb to try externally if you suffer from cold sores. The infused oil and salves made from the flowering tops are helpful herbal remedies for nerve pain, sore muscles, sciatica, and other kinds of aches and pains.
Related Recipe on Our Site: How to Make St. John’s Wort Oil & Salve
Who should not use St. John’s wort?
If you’re on any type of medication, pregnant, or nursing, check with your doctor before taking St. John’s wort internally. It can interact badly with several types of common medicines, and can be especially problematic for those on medications for depression.
External use is often fine, unless you’re on a medication that causes extra sun sensitivity. To be certain and safe, always check with your prescribing doctor before using St. John’s wort.
References & Further Reading
Cech, Richo. Making Plant Medicine. Williams, OR: Horizon Herbs, 2000. Print.
Hypericum Online (2022): Hypericum perforatum L. Published on the Internet; https://hypericum.myspecies.info/taxonomy/term/637. Accessed on: 23 Jun 2022.
Stojanović, G. et al. Do other Hypericum species have medical potential as St. John’s wort (Hypericum perforatum)? Current Medicinal Chemistry. 2013;20(18):2273-95. doi: 10.2174/0929867311320180001.
WFO (2022): Hypericum L. Published on the Internet;
http://www.worldfloraonline.org/taxon/wfo-4000018759. Accessed on: 23 Jun 2022.
Our articles are for information and idea-sharing only. While we aim for 100% accuracy, it is solely up to the reader to provide proper identification. Be sure to seek out local foraging classes and plant walks, and invest in mushroom and foraging guides suitable for the area you live in, since some wild foods are poisonous, or may have adverse effect.