Saint John’s wort is a shrub with abundant blooming which requires practically no care at all.
Key St John’s wort facts
Name – Hypericum
Family – Hypericaceae
Type – shrub
Height – 1 ½ to 6 ½ feet (50 to 200 cm)
Exposure – full sun, part sun
Soil – rich enough
Foliage – evergreen
Flowering – May to October
The penetrating yellow light that its flowers share is remarkable and will attract all eyes to the garden.
Planting Saint John’s wort
What is recommended is to plant Saint John’s wort in fall to support root development.
But still, you can also plant in spring, as long as you water abundantly at the beginning and over the following summer if the weather is hot and dry.
In a container, you can also plant in spring or summer, provided you water regularly.
- Find a very sunny spot for it.
- Saint John’s wort can tolerate any type of soil, even poor soil.
- Place the plant somewhere you’ll notice its bloom, because all those yellow flowers will boost your mood!
- Refer to our guidelines for planting shrubs
Pruning Saint John’s wort
Prune your Saint John’s wort at the end of winter or at the beginning of spring, before the first buds start opening up, to ensure you’ll have optimal blooming.
Pruning every year isn’t necessary, but if you run the shears along the bush every 2 or 3 years, you’ll ensure your Saint John’s wort will keep a compact bearing. Occasionally, a growth spurt will hit a single branch and make it grow long and leggy. Don’t be afraid to cut it shorter if it’s not growing in a direction you want it to go: it will branch out and make the shrub grow denser, and you’ll get more lush blooming later on, too.
If the foliage has dried out and the shrub looks bare and sparse, feel free to cut back to the ground and new shoots will start growing from the stump.
- St John’s wort can take severe pruning when performed at the right time (early spring).
Deadheading St John’s wort
St John’s wort is a repeat-blooming flower. Removing wilted flowers will encourage new blooms.
However, because fresh flowers grow alongside forming fruits, this sometimes isn’t very easy, depending on the variety and the size of the flowers.
Learn more about Saint John’s wort
A very appealing shrub with distinctive yellow flowers, Saint John’s wort is also a herbal plant used by many in herbalism to fight depression!
It is also liked for its evergreen leafage.
Its name, Saint John’s wort, comes from the day it can usually be harvested in Europe, the Feast of Saint John. A particularly renowned species is Hypericum perforatum, which has small translucent glands within the flesh of its leaves. If you look through the leaves towards light, you’ll notice uncountable tiny holes.
Since this is an easy plant to grow and care for, you’ll have great results thanks to its hardiness.
In rocky ground, shrub beds, or even in pots or garden boxes, place it wherever you’re certain to see it so that the bright colors and beautiful flowers may light up your day.
Saint John’s wort is found either as ground cover or as a shrub, which makes it an ideal plant to grow in the ground and in pots.
Most Saint John’s wort varieties are herbaceous plants.
Interesting Saint John’s wort varieties
Hypericum andosaemum – This is the ideal specimen to set up low-lying evergreen hedges. This variety never grows any taller than 32 inches (80 cm) and bears cute little yellow flowers.
Hypericum citrinum – As its name shows, its flowers are a luminous ornamental lemon-like color.
Hypericum inodorum – This very hardy and resilient Saint John’s wort will also bear innumerable flowers.
Hypericum moserianum – The mottled pink and green leaves make this one particularly appealing. Floral buds are pink and the flowers burst to reveal a striking yellow hue.
Hypericum patulum ‘hidcote’ – Considered by many to be highly ornamental, this Saint John’s wort bears very many flowers and truly illuminates your garden.
Smart tip about Saint John’s wort
It also makes for great hedges, because its rapid growth will quickly break the view to and from your neighbor’s.
Just remember to prune it very early in spring because flowers will only appear on new sprigs that will start growing in the middle of spring.
It would take me way more than a day to rid of the SJW in my lawn. More like 365 days would be needed. My hedge is currently about 3 feet high. So I can expect it will likely grow to 6 feet. it surrounds my 1/2 acre area. Maybe a brushcutter is what I need. I am not familiar with these. Does it start with a pull cord or are there electric ones? I can’t pull a cord . I’m 76 years old. Do you think i could handle one?
It does sound like you’ve got your gardening work cut out for you: all SJW! Keeping your hedge at 3 feet/1m high will be easiest with a hedge trimmer. Keep a secateur, loppers or a small handsaw nearby to cut any larger branches the first time you trim it. After that, the hedge trimmer will be enough.
A brush cutter is if you want to remove the Saint John’s wort hedge entirely, since it’s more designed to cut at ground level, not at waist or shoulder height. The distinctive feature of a brush cutter is that it has a short, steel blade which can cut stems up to an inch across. There are a few electric ones, usually they have these small batteries that hold for around 30-50 minutes before they need recharging. A few of the electric ones are lightweight, I’d recommend renting or borrowing one first to try it out before buying one outright.
Pull cord models which usually can go for 2 hours before you need to refill with gas are usually heavier, vibrate more, and are noisier.
For weeding out the lawn, it does feel like a big job! When I have long tasks like that, I like marking a portion out with a bright-colored rope or a few sticks and only focus on that part… moving it the next day or week till the work is done!
The other option is to start your lawn over from scratch, but there must be so many SJW seeds around that it’s probably not the grass that will win out!
Thanks for the tips. i know it will be a lot of work. At least I know some of the tools I will need before I tackle it. I’m not sure I will live long enough to get it done. I like how you try to put it into smaller more manegable tasks. That way it is not so overwhelming.
I have a ground cover of St. John’s wort which is invading my lawn. how can I control that. Also my St. John’s wort is more like a hedge now. How tall will it get if I don’t prune it? What is the best way to t rim or even mow it down.?
Hi Pat, it seems that the self-sowing is getting out of hand! One way is to simply take a day and pull any sprouts out from your lawn. Also, repeated mowing won’t work very well, because St John’s wort is sometimes chosen to replace lawn grass: so it can cope with being cut short! To prevent getting too many new shoots, go through the hedge periodically and remove/cut branches that have berries. Less berries means less invasive sprouting.
As for the hedge height, it’ll grow several feet more if you don’t prune it, up to 2 meters/6 feet for most varieties. The good thing is you can cut it back drastically at the end of spring, that would be next year at this point, around May. Any technique to cut it back will work fine, from hacking at it with a brush cutter to pruning branches off with a secateur. Depending on the thickness of some branches, a hedge trimmer might not cut it.
How does it go to dig up st Johns wort in the nature and transplant it at home? …in Norway
Ideally, you’d transplant the shrub in fall, before it freeze. You’ll have to protect the plant against the cold during the first year. Note that it is only hardy to -8°C (18°F) in normal conditions, and if in excellent conditions (draining soil, sheltered from wind), it has been known to resist -14°C which is 7°F.
If I’m not mistaken, this means you can plant it in most coastal areas, and also a bit inland in southern Norway, and it should survive winter (except that you have to protect it for the first winter).
I have recently planted a St.Johns Wort and it has started to grow very well. However there is one horizontal branch which has grown quite long and has no buds, just leaves. Should this branch be cut off ?
Hi Stuart, you can cut it shorter, but I wouldn’t cut it off entirely. Cutting it shorter will lead to branching out. This will make the shrub denser, and secondary growth tends to have more blooms. Possibly you did an excellent job planting the shrub and it’s really having fun spreading out, so make sure you know what shape and space you want it to have later on and use that as a guide to prune anything that juts out.
Thank you very much for your information and quick response.
Why are the leaves on my Sunburst hypericum curling and not flowering.
Hi Mary, it depends on the situation. Not flowering is because the plant is dealing with some sort of survival stress: whatever is making the leaves turn yellow. Until the plant feels safe, it won’t flower.
So why would leaves curl on hypericum? Several possibilities:
– if it’s in a pot and the drainage hole is plugged, then excess water won’t flow out and the soil stays soggy. This is overwatering, and leaves usually turn yellow and drop off before they turn brown. Repot in a pot that has a hole under it that drains well, and layer about 2 inches of gravel or clay pebbles. If it’s in the soil and symptoms are the same, maybe the soil doesn’t drain well enough. It would be best to try to delicately dig the plant out and add lots of drainage material under it like coconut coir, clay pebbles or gravel again, and the like. Another sure way to help is to raise the growing bed so excess water will always drain away.
– if, on the other hand, leaves turn brown before falling off, then it might be underwatering. In a pot, it needs water very regularly, almost daily in Summer. In the soil, it can go for longer without watering but if it’s just been planted, it won’t have far-extending roots yet. A good solution is to go for hydrogel garden beads, these store water for longer periods of time if you can’t water that often.
A last possible cause for curling leaves on hypericum is aphids or thrips. Follow the links to learn how to treat against these.
Why did my st John’s wort stop blooming and how can I fix it?
Hello Nancy, there are three possible reasons that can explain why it isn’t yet blooming.
First, perhaps the plant was “forced” a bit in the nursery (meaning temperature and moisture were adjusted to make it bloom earlier than naturally, for it to bloom on the selling stand). When a plant is forced like that, it usually needs a full year to recover and “get back in sync” with nature.
Second, perhaps there’s a relative lack of phosphorus and potassium in the soil. If there’s too much nitrogen, the plant will produce lots of leaves but it won’t bloom easily. Try adding a fertilizer that has P (phosphorus) and K (potassium) with less or no N (nitrogen).
Thirdly, and probably the case since most people have this problem: to bloom best, Saint John’s wort needs full sun. Perhaps you can try adding a white reflector behind the plant for a season, it should increase the likelihood of blooming.
St. John’s Wort
this is a question not a comment – does anyone know if this should be deadheaded to encourage more blooms?
Hello! Deadheading of St John’s wort is sometimes impractical, especially for species that bear flowers and fruit simultaneously like H. androsaemum. But that’s exactly when it’s most effective, because diverting growth from fruit production will lead to more new wood growth and flowers. So the short answer is yes, if you’re patient enough to single wilted flowers out!