Arnica spp.
Arnica is a genus that includes around 40 species – 27 of which are found in the mountains of the northwestern US and Canada.
The most well-known species A. montanaIt is Other species are natives of North America, Siberia and northern Europe.
A. montana has long been known for its medicinal qualities – specifically in relieving inflammation and pain, as well as helping to heal bruises, sprains, and wounds, and acting as an antiseptic.
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The North American native is also known to have healing properties. A. chamissonis.
The climate crisis, changes in land use, and unsustainable harvesting of wild arnica has put some species at risk – including the commonly garden-grown species A. chamissonis – all the more reason to make a home for this herb in your garden!
In this guide, you’ll find everything you need to know about growing arnica.
Let’s begin by digging a little deeper into the botany and background of this significant plant.
What is Arnica?
Arnica is a member of the Asteraceae or sunflower, daisy, family.
This perennial is very hardy and can be found from Zones 2-9. The soil is acidic in its natural habitat, which includes alpine areas, woods, and high-altitude pastures.
They have oval, light-green leaves. The leaves and stems of these plants are usually hairy.
The flowers can be up to 3 inches wide and bright orange-yellow. Flowers bloom from May through August and in some places, even into early autumn.
The fragrance of the blooms attract pollinators Included are a variety of bees and moths.
Many species have underground rhizomes that enable them to spread rapidly and fill up the surrounding areas.
Cultivation History
Arnica has some fun common names – leopard’s bane, wolf’s bane, mountain snuff, and mountain tobacco. The leaves were historically used as tobacco substitutes.
The medicinal uses of this group of perennials date back to the 16th Century. Arnica can be found in creams and cream tinctures.
However, it’s important to note that arnica extracts should not be applied to broken skin. Although it’s beneficial for most people, some may develop topical skin dermatitis.
This herb can potentially be toxic, so it should only be applied externally.
Today, Romania produces most of the world’s wild-harvested arnica, and Germany is the largest importer.
Arnica Propagation
Divide your mature arnica to get more plants.
It is also possible to start plants from seeds, but it takes more time. You can pick the best method for you by comparing both methods.
From Seed
Seeds don’t remain viable for a long time, so using fresh seed is a good idea.
Place the seeds in a plastic baggie with peatmoss in the fridge for at least 2 weeks, and as long as 12 weeks.
You want to? Start seeds indoorsPrepare a seed tray by filling it with moist potting soil. To germinate these seeds, they need light. So sow them just above the soil surface or barely cover with potting mix.
Set up the seed tray on a warm surface with indirect, bright light.
Germination is slow – seeds will germinate in three to four weeks. When the seedlings reach three to four inches in height and have developed roots, you can transplant them to the garden.
You can also plant seeds outside in the early fall, and let the winter months take care of stratification. Alternately, you can sow stratified seed after the danger of frosts has passed.
The Divisions
Arnica can be easily multiplied through dividing mature plants in the springtime or falltime after their second or third growth year.
You can do this by watering your plant thoroughly one or two days in advance of the division.
Prepare the location where you will be placing the new divisions by digging a hole that is a bit wider than the root system and deep enough to allow the crown of the tree to sit flush on the surface.
Cut the stems and foliage so they’re six inches from the ground. Dig around the entire plant and underneath. Remove any loose soil from the plant by shaking it off.
Be sure to include a section of the rhizome as well as a few stems that have leaves. Look at the clump and cut off any damaged rhizomes.
Plant the new division with the rhizome barely visible above the level of the soil. Water in well.
Arnica: How to Grow it
The arnica plant grows naturally in part shade or full sunlight, but to get the best flowers, choose a location with full sunshine.
This herb grows best in sandy or loamy soil with a pH between 5.5 and 7.5.
You will need to keep the soil slightly moist – these plants don’t tolerate drought.
Aim for a happy medium – moist soil that’s not waterlogged and not bone dry. It should always feel like an incredibly well-wrung out sponge.
If you live in a windy area, you may need to stake your plants so they don’t fall over.
In the spring, give your plants a small dose of fertilizer that has a low concentration of nitrogen.
Growing Tips
- Grow in full sunlight
- Provide a sandy or loamy soil with a 5.5-7.5 pH.
- Maintain even moisture.
Maintenance
Once it is well-established, arnica will not need much care, though if you don’t want it spreading to the rest of your garden, you’ll need to cut it back.
The roots have a tendency to spread so make sure to plant it somewhere where this isn’t a problem. Arnica is not a good competitor with weeds despite this tendency.
Keep flowers blooming all summer long. Deadhead all wilted or fading flowers.
Divide the plants during the spring or fall every few years to maintain the plant’s vigor and keep it looking great.
Come fall, you can cut back the dead or dying foliage to keep the garden looking tidy, but this isn’t essential.
Arnica Cultivars and Species to Select
It may take a little searching to find arnica seeds. However, specialty herbal or medicinal seed suppliers are likely to carry them.
A. montana ‘Arbo’ is the only commercially recognized cultivar, and it can be found from specialty seed suppliers. It was developed by German scientists in the 1980s.
A. chamissonisThe North American native is popular and is easier to grow than its European cousin.
A. chamissonis
Find out more about A. chamissonis Seeds Earthbeat Seeds – Available from Earthbeat Seeds.
Pests and Disease Management
Arnica is resistant to many pests and diseases but is more susceptible in conditions of high moisture or waterlogged soil.
Here’s what to watch out for when growing this perennial:
Pests
There aren’t many pests that will go after your plants – but snails are one to look out for.
Snails
Arnica is a snail favorite – and they can do some serious damage to your plants by munching on the leaves, and leaving irregular, smooth-edged holes behind.
The shiny mucous trails left on the leaves are a sure sign that snails are the culprits.
You can control snails in a variety of ways if you find that they are a problem.
Picking them off by hand can be quite effective – albeit time-consuming. After late afternoon, water your plants and surrounding area to draw the snails out.
When it’s dark, use a flashlight to find them – squeamish pickers are advised to Wear gloves!
Check for snails daily, and be thorough – they’ll likely be hiding in the arnica plants! Once you notice that there are fewer snails around, a weekly handpicking is enough to keep them under control.
Another way to catch and drown snails is by putting them in a liquid. Beer is the most popular option, but sugarwater with yeast added works as well.
To trap snails this way, place the liquid in a bowl that they can’t crawl out of – a few inches of liquid should do. Bury the container with its top leveled with the soil.
The traps are only effective within a radius of a few feet, so you will need several traps if the arnica patch is big. Your traps should be emptied and refilled every few days.
You may want to use a copper barrier if your plants are located in a planting area. The copper reacts to the slime produced by snails, which causes a sort of electric shock.
Wrapping copper foil or using tape can be used to create a copper barrier around a planting box. It will work until it tarnishes. You can clean it with vinegar to get it working again.
The longer-term option is to install a vertical copper mesh. It doesn’t need to be tall – one inch above the soil and one or two inches buried beneath the soil is enough to prevent them from getting in.
The cultural controls can also be combined with chemical controls. Iron phosphate-based baits can be used around children and pets.
Slug Magic
Slug Magic is an excellent choice. Arbico Organics offers a wide range of products.
Spread the bait on areas where arnica is being damaged by snails, but not directly on the plant. The bait will feed if you lightly water it.
Learn more about Our guide will show you how to handle snails and slugs..
The Disease
Crown rot is a disease that you should be aware of when growing arnica. Read on to find out what to do if this happens.
Crown Rot
Crown rot can be caused by soil-borne pathogens. It is usually necessary to remove the affected plant from the garden.
Initial symptom is wilting. Leaves may turn yellow or die.
Some rhizomes that survive the infection may grow back, but they will still likely show signs of disease.
Prevention is key to preventing crown rot. Plant in soil that drains well and avoid overwatering. If necessary, amend the soil at planting time.
If your garden soil doesn’t drain well, then consider growing your arnica in Raised beds.
Harvesting
You may get a small crop in the first year if your arnica is healthy. You will not see a large harvest for two to three years.
Arnica flowers in the east of the United States and Canada from late June through to summer. Arnica may continue to bloom in the west of North America and Canada until early autumn.
Arnica flowers can be harvested by hand. Simply pull each flower head from the stem – I love the satisfying pop! It makes a sound
Harvest the flowers when they’re fully opened. Wear gloves as the stems can be scratchy. It is best to pick in the early morning, after dew evaporates.
This herb has a staggered blooming period which means you’ll need to harvest the flowers continually, every three or four days during peak blooming.
Arnica Uses
Arnica is used as a cream and in other topical products.
Remember that no part of the plant should be ingested – it should only be used externally, with the exception of homeopathic medicines which come in extremely diluted doses.
You can preserve your herb by drying its flowers. To do this, place blossoms in a single layer on a drying rack or paper-lined tray in a warm location with temperatures of at least 70°F, out of direct sunlight and with good airflow.
If you’re using an electric dehydrator, the temperature should remain around 100°F and no more than 113 °F (45°C) to maintain the active components.
Once they are dry, the blossoms will look puffy and as if they’ve gone to seed – this is totally normal!
You can make a tincture from the flowers. Fill a glass bottle fitted with a tightly-fitting cap about a third full of flowers. Add rubbing alcohol until all the flowers have been covered. Then, close the lid.
The tincture should be kept on the windowsill to infuse for at least four weeks. Strain the tincture, throw away the flowers and store it in a dark, cool glass jar.
You can use it to soothe sore muscles.
Quick Reference Growing Guide
| Plant Type: | Herbaceous perennial | Growth Rate | Fasten your seatbelts |
| Native To: | Central Europe, North America, Siberia | Water Needs | Moderate |
| Hardiness (USDA Zones) | 2-9 | Tolerance: | Poor soil shade |
| Season: | Spring, summer, fall | Maintenance: | Low-cost |
| Exposure: | Full sun | Soil Type | Sand, loamy |
| Time to maturity: | 3 to 5 years | Soil pH | 5.5-7.5 |
| Spacing: | 6 inches | Soil Drainage | Well-draining |
| Planting Depth | Transplanting: 1/4 inch depth of rootball (seeds) | Attracts: | Bees, butterflies and moths |
| Height: | The 1-2 foot | Companion Planting | Rhodiola, yarrow |
| Spread: | 1.5-3 feet | Family: | Asteraceae |
| Growth Rate | Moderate | Genus: | Arnica |
| Common pests and diseases: | Crown rot; Snails | Species: | Angustifolia, chamissonis, cordifolia, montana |
Nature’s Remedy
Arnica is a beautiful flower that has a sunny disposition. It can also be used as a medicine.
Growing arnica helps to preserve endangered species by providing food and habitat for pollinators. Arnica has many benefits. Try growing it in your own garden!
Have you got any tips for growing arnica? Tell us in the comments!
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