How To Grow St John’s Wort
One of your more unusual herbs to grow at home St John’s Wort has a lot to offer to even the non-herbalists out there!
Growing to a compact 24 inches this woody perennial will become a reliable source of color in your garden from late Spring and through Summer. Producing an abundance of yellow flowers, St. John’s Wort (Hypericum Perforatum) will offer wonderful fragrance to all who pass by.
Whether you choose to grow from seeds or to purchase a more mature plant you are on to a really great display of foliage with a low maintenance plant. We love St John’s Wort for many different reasons so let me explain a bit more!!
How To Grow St John’s Wort From Seed
If you are thinking about starting from seed you can look online and buy St John’s Wort / hypericum perforatum seeds here. It can be difficult to get more specialist seeds from your local nursery and often there is an additional cost attached this.
- You can sow St John’s Wort indoors, the timings can be tough to judge some years but you are looking at sowing between 6-8 weeks before the fear of frost has passed. You can sow directly outside once the forecast is clear for frost.
- We use biodegradable pots made from newspapers and aim to plant 3-4 St John’s Wort seeds per pot. They are cheap to make and will allow easy transplantation of the seedlings without disturbing their roots. Have a look here to see how to make these pots.
- Use a reasonable compost for this task and fill the pot. Now push each seed in, ensuring to leave the top uncovered to allow for light to penetrate to your seed. This is essential for all germination of St John’s Wort seeds. We have played around with popping in the fridge overnight beforehand to allow it to ‘wake up’ in warm soil. We have also soaked our hypericum seeds overnight, but again it is unclear whether this made much difference to germination rates. If we are being completely honest the results were not conclusive and you will need between 3-4 seeds for an almost guaranteed germination in each pot.
- Do not soak your pots with water, allow a damp soil to start and keep an LED lamp on if the weather is typically gloomy. You can grow St John’s Wort in the UK and USDA zones 3-10 with a lot of success. Making sure to protect the early seedlings and to plant in an area with plenty of sunlight.
- After 10-20 days you will see germination has taken place, for best results keep the soil moist but not wet. A constant temperature will also be key to success here, 70 degrees should be adequate and most heated propagators will do the trick.
- Once the seedlings are between 2-3 inches in height you may need to plant on. This is where the biodegradable plant pots come in handy. St John’s Wort is not too fussy about many things but we don’t like to risk disturbing the roots, so we take the pot and transplant it whole. If you have two seedlings in a pot, thin out the weaker of the two.
- You can easily plant your St John’s Wort into a pot or container. Remember that it will likely grow to a height of around 1-1.5 meters, so give yourself a larger space to fill.
- There is a lot to be said for the hardiness of this compact perennial shrub, but St John’s Wort can be invasive. Therefore if you want to plant it into the ground you may want to think about keeping it in a pot, but lowering that into the ground and covering. This will give the image of it being part of your border, but in reality you are stopping it from taking over the rest of your garden. Remember this when watering though as it will require a lot more care in the hotter weeks of Summer.
- Give your St John’s Wort between 18-24 inches apart to allow for a bushier foliage. The abundance of flowers that is so associated with St John’s Wort will come naturally then as well!
Water as you would do for so many herbs and be sparing but regular. Always make sure you have adequate drainage. St John’s Wort is not fussy about soil quality as long as there is adequate drainage. We recommend a mulch during the hotter weeks as this will lock in moisture without the fear of over watering.
You can also propagate St John’s Wort by cuttings, layering, seeds or division of clumps.
How To Propagate St John’s Wort By Cuttings Or Layering
As a woody perennial St John’s Wort is low maintenance and easy to propagate.
- To propagate St John’s Wort by cuttings wait until the shrub is starting to bud. This will mean it has the best chance of taking root. Summer should be the time you can start looking. Early morning is the best time for cuttings as the plant is warming up and getting ready to grow all day!
- Take the cutting with some leaves on as well, about 5-7 inches in length should be fine. You will need to trim back the lower leaves of the St John’s Wort to stop it rotting in the water or soil.
- Mix perlite with a peat-free compost, go as far as a 50:50 mix. Use a pot with plenty of drainage holes as well as a handful of pebbles in the bottom. Drainage is the key to success here! We use a terracotta pot to retain heat and moisture.
- Use a similar size twig to dib a hole in the soil mixture to then pop your cutting into. Using the outer edge of the terracotta pot will allow multiple cuttings into each pot.
- Use an organic rooting gel and dip the exposed heal of the cutting into this mixture. There is a lot of evidence to suggest that raw honey will perform the same role. Basically it is there to fight off fungal infestations. These are the enemy to successful propagation of your hypericum.
- Moisten the soil, but do not soak it. Then cover with a clear plastic bag. This will trap in moisture and allow plenty of sunlight in as well. It helps with not over watering your St John’s Wort cuttings.
- Check on your hypericum cuttings regularly as the lower leaves may turn brown and need removing. You may also want to check for any signs of rotting as one cutting can contaminate the whole batch.
- 3-4 weeks after propagation has started you should be able to perform a gentle tug test. Very gently pull at the cutting, if you feel resistance you know you have a root system starting. St John’s Wort will be robust once it is a mature plant but for now keep looking after it as if it was a tender plant.
- Remove the plastic covering and start the hardening off process. Allow your hypericum cuttings to sit outside in the sunlight, but bring into the warmth in the evening. Then gradually water a little less and transplant into a pot or the ground.
- Congratulations you now have a new St John’s Wort plant! They do make great gifts as they are so easy to care for!
Propagation of Hypericum by layering can be a little fiddly but very rewarding.
- Choose a long stem from your hypericum that can easily reach to the ground and back up again. Pick it in Summer when the sap is rising and the plants are in growth mode. Softwood is the best way to go and is flexible enough to make this work.
- You will be pinning down and middle section of the St John’s Wort stem and growing a new plant from this middle section. So fill a pot with compost mixed with perlite to allow for adequate drainage.
- Remove the middle section of the softwood’s leaves. Then using a sharp knife remove the outer greenery. This will create opportunities for roots to grow.
- Make a hole in the soil and bend the Hypericum stem down into position. Cover with soil and we use a little peg either side to just weigh it down.
- $-6 weeks of watering and making sure that there is as little movement as possible and you should be able to perform a gentle tug test. If it offers resistance it means that a root system has started. Now cut the mother side and you are free to move the pot containing the new St John’s Wort plant.
- Layering your St John’s Wort is a good idea if you are limited for space, but overall we would still recommend clippings for return on investment.
Growing St John’s Wort In Containers
Growing in pots or containers is a gamechanger. The main reason being St John’s Wort does have a reputation as being a bit of a garden bully. Taking over whole areas and choking out neighboring plants. You can also get some lovely combination planting with other herbs, we choose chamomile to underplant our hardy shrubs with to great effect.
- With growing any plant in pots the first priority is preparing your pot or containers. St John’s Wort is no exception and this hardy perennial herb is in no way fussy, other than for drainage.
- We like to offer all of our herbs a homemade compost, rich in organic material. More for drainage than anything else. Hypericum does not need fertilizing as such, but this slow release mixture will also offer additional nutrients.
- Go for a pot deep enough to incorporate the root system of St John’s Wort and we recommend a pot one foot square for each plant. This will allow adequate sunlight hours.
- Water your plant once it is settled in it’s new pot. Monitor to make sure it is kept moist but never wet. This is so important during raining periods as soggy roots are a no-no for hypericum plants.
- Do not be afraid to move your pots around to follow the sun or to shelter from the rain. St John’s Wort is low maintenance and will not mind too much wind.
- Overwintering is straightforward and we mulch to then prune in late Spring.
- To prune your St John’s Wort you can take the top third off and it will encourage strong growth that year.
- Use your cuttings for propagation and keep the gift of herbalism alive!!
How To Harvest St John’s Wort
Wait until the blooms have just passed their best and then take around the top 4 inches. You can air dry them in bundles or use a dehydrator. Then store the flowers in airtight containers. For a full guide on drying herbs have a closer look at this article here.
Possible Benefits and Uses For St John’s Wort
Also known as Goatweed, Klamathweed, Hypericum, Chase Devil, Amber, or Touch-and-Heal. St Johns Wort has a history closely associated with healing and medicine. Historically thought to have been named after John The Baptist.
- One benefit that does not need to be scientifically proven is how beautiful the flowers are. They are lightly scented and you will find a host of wildlife making your St John’s Wort it’s home. From bees and other pollinators to ladybirds feasting on the aphids.
- St John’s Wort is great as a companion plant and where you want to bring in pollinators too.
- In the garden hypericum is great towards the back of a border as it offers a really stable presence. The height is great and it’s that architectural structure that so many borders need. Being a perennial helps massively cut down on the maintenance that a border needs as well.
- As an over the counter herbal medicine aimed at easing the symptoms of mild to moderate depression. It is always a good idea to use herbal medicines after consulting a qualified medical professional as there can be some interference with existing prescribed medicines. You can purchase A. Vogel St John’s Wort tablets here.
- St John’s Wort is also used in tablet form to treat SAD and low levels of anxiety. Only after consulting with your GP and talking through options with them.
Where To Buy St John’s Wort In The UK
We bought Hypericum ‘Tricolor’ (2 Plants) St Johns Wort Plants in 9cm Pots via Amazon Here and have been very happy with the condition they arrived in. The variegated leaves offer a great display year round as well. This meant that this variety was perfect for our little border beside the chicken coop. My motto is always to stuff the garden with as much as possible to get a full year round display.
What Next & Further Reading
- Yarrow (Achillea millefolium) – A Grower’s Guide To Success
- How To Grow Angelica In The UK
- Mugwort – How To Grow And Use
Get stuck in and give it a go, just remember that St John’s Wort is invasive and can happily become a medium sized perennial weed. Albeit a beautiful lightly scented one!
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