Hypericum Perforatum
Many gardeners know about hypericum perforatum because of its long tradition in herbalism, but it is wonderful for so many other reasons! H perforatum is also a great garden plant for its soil erosion control abilities, its ground cover growth habit, and it’s bright yellow flowers that attract pollinators to your property.
H perforatum is more commonly known as the St John’s wort plant, but also is known under the names of Klamath weed, common st johnswort, goatweed, tipton weed, devil’s scourge, rosin weed, or God’s wonder plant. It is part of the hypericaceae botanical family.
The hypericum spp flowering plant gets its name because the plant blooms and is harvested right around the time of the summer solstice, which is also St John’s Fest Day. Traditionally this herb was hung on doorways to ward off evil spirits and to protect members of the household from sickness.
Gardeners love this plant because once it is established, it requires absolutely no care. You should grow St Johns wort for many reasons, but you’ll have to read the rest of the article to find out why!
What do St John’s Wort Plants Look Like?
Growth Habit
Starting underneath the soil, St John’s wort plants grow from underground creeping rhizomes. A rhizome basically acts a storage facility that contains all of the moisture and nutrients necessary to keep a plant alive in harsh conditions.
These creeping rhizomes encourage the plant to spread quickly and vigorously, and they are also part of the reason why these plants are considered as being a noxious weed.
From here, the plant will grow woody, red stems that stand erect and branch out near the upper section. They will usually grow to be around 3 feet in height, but will sometimes develop a ground cover growth habit.
Leaves
St John’s wort plants are deciduous, meaning that they bear leaves that change color and fall away as the cold weather approaches. Leaves are oppositely arranged on the stem and are stalkless.
Each leaf is a bright yellow green color that have scattered transparent dots all over the surface, which gives them the appearance of being perforated, hence the latin name. Smaller leaves will grow near the top of the stem and they slowly increase in size the further down the stem you go.
Flowers
St John’s wort plants are a perennial plant type, meaning that they bear flowers that will sprout up each spring as long as their ideal growing conditions are met and maintained.
St John’s wort flowers will bloom in the mid to late summer and last all the way through to autumn. Each yellow flower is comprised of 5 petals and many many long stamens. A flower is also decorated with black dots.
The yellow petals adorned with black dots are a way to attract pollinators to an area. Once a flower is fertilized it will produce bright red/pink berries in the summer time that are then eaten and seeds are dispersed far and wide.
What are some Other Hypericum Species?
Shrubby Saint John’s Wort (Hypericum Prolificum)
Shrubby Saint John’s wort is a mound forming shrub that grows to be about 3 feet in height. It is an excellent ornamental plant that is often used for hedging or as a border plant.
Hypericum prolificum can be identified by its upright branching stems of red or purple, and green ovate leaves that grow in opposite pairs. H prolificum has that classic yellow flower color with super long and showy stamens.
Great St Johnswort (Hypericum Calycinum)
Great St Johnswort is a low growing shrub that also goes by the names of Aaron’s beard, creeping St John’s wort, or Jerusalem star.
Hypericum calycinum is an evergreen shrub that bears ovately shaped, bright green leaves that grow in opposite pairs. H calycinum also grows a yellow flower with showy stamens, but it is said to resemble a rose.
Where is St John’s Wort a Native Plant?
One of the most valuable pieces of information you could learn about growing a new plant is learning where it is considered a native plant. This better enables you to mimic those growing conditions, therefore keeping it as happy as possible in other places in the world!
The St John’s wort plant can be found growing wild all throughout the more temperate areas of Europe and Asia. They thrive in areas like pastures, prairies, and disturbed lands.
They are so good at growing in fact that St John’s worts are considered as being a noxious weed in nearly every other place it has been introduced to, including South America, North America, South Africa, and Australia.
These flowering plants can live happily outdoors all year long in USDA growing zones 5 through 10, but should be brought indoors during the colder winter months of the year.
What are the Ideal Growing Conditions of St John’s Wort Plants?
Now that we have all of the preliminary information out of the way, it’s time to learn about how to care for a St John’s wort plant of your very own!
Good news: St John’s care is remarkably easy. Once these plants are established they will require absolutely nothing from you. But in order to get them properly established, here are a few tips and tricks:
Soil Type
Something wonderful about these plants is that they can tolerate so many different soil types. They can handle sandy soil, clay soil, rocky soil, loamy soil, or a combination of them all!
They also prefer to live in soil that is either acidic or slightly alkaline, and soil that is high in fertility. A great way to accomplish these things is by incorporating some compost to the soil mix at the beginning of the growing season.
Compost is a wonderful way to increase the drainage of the soil, while simultaneously increasing the nutrient level and achieving the desired level of acidity! They don’t perform too well in poor soil.
Water Level
Another cool thing about St John’s wort plants is that they are superbly un-picky about the amount of water that they receive. A rather rare quality in a plant: they are both tolerant to drought and to flooding!
As the plant is first getting established it’s important that the soil remains partially moist, but once the plants are all settled in you will only need to water it if there is an extended period of drought. Otherwise, natural precipitation will suffice.
Sun Exposure
The one thing that St John’s wort plants are a little bit picky about is the amount of sun exposure that they receive. It can be a little bit tricky to find the perfect balance!
If a specimen is planted in an area that receives too much sunlight, the plant can sometimes develop leaf scorch. If a specimen is planted in area that receives too little sunlight, sometimes it won’t flower as enthusiastically.
It is best if the plant is planted in an area that receives full sun exposure in the morning, which then receives partial shade in the heat of the afternoon sun.
Temperature
St John’s worts plants aren’t too picky when it comes to temperature. They perform perfectly well in temperate climates and are tolerant to both hot summers and cold winters.
They can exist happily outdoors in USDA growing zones 5 through 10, but should be brought indoors for the cold winter months outside of those zones.
Fertilizer
St John’s worts plants are heavy feeders and they will benefit from receiving fertilizer at the beginning of their growing season.
You can either use a water soluble fertilizer or you can incorporate some compost into the soil mix. This can be done in the spring right before the beginning of their active growing season.
Pruning
Since St John’s worts plants are such enthusiastic growers, it can be a good idea to do a heavy annual pruning to keep their growth in check! Do this in the early spring before they are due to start their spring growth. Pruning will help keep their appearance tidy and keep them healthy too!
How do you Propagate a St John’s Wort Plant?
And now for the final step in your journey towards being a professional on St John’s worts: how to propagate a specimen of your very own! The best way to do this is by starting seeds indoors first and then transplanting them outside. Here are some steps to get you started:
1. Your St John’s seeds should be started indoors about 6-8 weeks before the estimated last frost of the season. Plant a seed in individual cell packs, water well, and wait until seedlings are 3 inches tall.
2. Once this happens, they are ready to be transplanted outdoors. Pick a spot on your property that receives partial shade in the afternoon, and in soil that has plenty of compost mixed in.
3. Dig holes that are around 24-36 inches apart from one another. Gently plant the seedlings into the holes, fill the hole, tamp it down, and water slowly and deeply.
4. Maintain soil moisture as the plants are getting established. After the first time they flower, they are pretty much good to fend for themselves after that!
Happy Planting!
FAQs
Are St John’s wort plants deer resistant?
Another reason to love St John’s wort plants is that they are entirely resistant to grazing from larger pests like squirrels, rabbits, and deer.
Can a St John’s wort plant survive winter?
St John’s wort plants grow from creeping underground rhizomes. These rhizomes act as a storage facility that contains all of the necessary nutrients and moisture to help keep the plants alive in those harsh winter months.
Are St John’s worts evergreen plants?
There are some hypericum spp species that bear evergreen leaves, meaning that they will remain green and on the shrub all year long, whereas there are other species that are deciduous, meaning that they have foliage that will change color and fall off as the cold weather approaches.
Can St John’s worts be grown indoors? Can a St Johns wort plant be grown in a container?
A St John’s wort can be grown indoors as long as it is kept in a south facing window. Just remember that the container that it is kept in needs to be large enough to contain those spreading rhizomes. When grown in a container they will also need to be divided every few years to ensure that they have enough room to grow.
Though pollinators won’t be able to fertilize the plants – so they won’t produce those little red berries – this does prevent the St John’s wort population from growing out of control and becoming an invasive plant on your property.
Is St John’s wort a perennial plant?
St John’s wort is a perennial plant type, meaning that it will produce flower blossoms every early spring as long as its ideal growing conditions are met and maintained.
What is another common name for saint johns wort?
There is more than one common name for saint johns wort, including the names of Klamath weed, common st johnswort, goatweed, tipton weed, devil’s scourge, rosin weed, or God’s wonder plant. It is part of the hypericaceae botanical family.
What USDA growing zone can St John’s wort plants grow in?
The St John’s wort plant can be found growing wild all throughout the more temperate areas of Europe and Asia. They thrive in areas like pastures, prairies, and disturbed lands.
They are so good at growing in fact that St John’s worts are considered as being a noxious weed in nearly every other place it has been introduced to, including South America, North America, South Africa, and Australia.
These flowering plants can live happily outdoors all year long in USDA growing zones 5 through 10, but should be brought indoors during the colder winter months of the year.
What are the health benefits of St John’s wort?
Certain studies have shown that taking St John’s wort is a great and natural alternative to antidepressant drugs and can help with moderate depression symptoms. It can also help ease symptoms of PMS and menopause.
How often should a St Johns wort plant be watered?
Another cool thing about St John’s wort plants is that they are superbly un-picky about the amount of water that they receive. A rather rare quality in a plant: they are both tolerant to drought and to flooding!
As the plant is first getting established it’s important that the soil remains partially moist, but once the plants are all settled in you will only need to water it if there is an extended period of drought. Otherwise, natural precipitation will suffice.
Where are St Johnsworts native plants?
St Johnsworts are native plants to the temperate regions of Europe and Asia.
Is St John’s wort an invasive species?
St John’s wort is considered as being an invasive species all throughout South America, North America, South Africa, and Australia. This means that its population cannot be controlled and it can cause health detriment to the local flora of the area that it has been introduced too.
Is St John’s wort drought tolerant?
Something great about St John’s wort plant is the fact that they are drought tolerant and they are also tolerant to flooding! This makes them great for a shrub border than can sometimes be submitted to less than ideal growing conditions.
Should a St John’s wort plant be pruned?
Since St John’s worts plants are such enthusiastic growers, it can be a good idea to do a heavy annual pruning to keep their growth in check! Do this in the early spring before they are due to start their spring growth. Pruning will help keep their appearance tidy and keep them healthy too!
Does St John’s wort prefer full sun exposure?
The one thing that St John’s wort plants are a little bit picky about is the amount of sun exposure that they receive. It can be a little bit tricky to find the perfect balance!
If a specimen is planted in an area that receives too much sunlight, the plant can sometimes develop leaf scorch. If a specimen is planted in area that receives too little sunlight, sometimes it won’t flower as enthusiastically.
It is best if the plant is planted in an area that receives full sun exposure in the morning, which then receives partial shade in the heat of the afternoon sun.
What is the ideal soil type for a St John’s wort plant?
Something wonderful about these plants is that they can tolerate so many different soil types. They can handle sandy soil, clay soil, rocky soil, loamy soil, or a combination of them all!
They also prefer to live in soil that is either acidic or slightly alkaline, and soil that is high in fertility. A great way to accomplish these things is by incorporating some compost to the soil mix at the beginning of the growing season.
Compost is a wonderful way to increase the drainage of the soil, while simultaneously increasing the nutrient level and achieving the desired level of acidity! They don’t perform too well in poor soil.
What is the easiest way to propagate a St John’s wort plant?
The easiest way to propagate a St John’s specimen of your own is by starting the seed in its own individual cell indoors, about 6-8 weeks before the last estimated frost of the season. It can then be transplanted outdoors to its forever home in your garden.
What time of year do St John’s wort flowers bloom?
St John’s wort flowers will bloom in the mid to late summer and last all the way through to autumn. Each yellow flower is comprised of 5 petals and many many long stamens. A flower is also decorated with black dots.
The yellow petals adorned with black dots are a way to attract pollinators to an area. Once a flower is fertilized it will produce bright red/pink berries in the summer time that are then eaten and seeds are dispersed far and wide.