Centranthus ruber [sen-TRAN-thus, Roo-ber] is a flowering perennial plant belonging to the family Caprifoliaceae.
The name for the plant is derived from Greek words kentron and anthos.
The former is translated to mean “spur” while anthos means flower.
Together, the words refer to the flower having a spur-like base.
The word ruber simply means red.
This is where its common name Red Valerian comes from.
Other common names include:
- Red valerian
- Fox’s bush
- Devil’s beard
- Jupiter’s beard
Noted for attracting wildlife and bright red flowers, these plants are used to line garden beds, boundaries, and along walls.
Native to the Mediterranean region, this plant has been introduced to many other parts of the world.
While pretty to look at, some consider the species invasive.
This is why you’ll find it frequently growing in urban wastelands.
Centranthus Ruber Care
Size & Growth
Red valerian plants don’t take too long to grow and flower.
If you plant them in well-drained, moderately fertile soil, they will thrive.
Within 2 to 5 years, you will be able to enjoy a fully-grown plant with all its floral glory.
With all growing conditions fulfilled, it can grow anywhere between 24” – 36” inches in height and around 20” inches in width.
Flowering and Fragrance
One of the reasons why the plant is preferred by gardening enthusiasts is it flowers profusely.
During early summer, flowering occurs sporadically.
The inflorescences are large and showy with small flowers less than 1” inch in size.
Leaves are dark, glossy gray-green with red flower colors.
They have five petals and a spur and appear in small round clusters.
Typically, they are brick or purplish-red and slightly fragrant flowers.
However, this can vary between deeper and bright shades of red.
The cultivar ‘coccineus’ is especially long-blooming.
Light & Temperature
Like many perennial plants, red valerian loves the sun.
Choose a location getting at least 6 hours of full sunlight to ensure the plant has lush foliage and abundant blooms.
The plant can tolerate part shade but does the best in the full sun.
Also, it doesn’t respond well to high humidity or very high temperatures.
United States hardiness zone 5 – 8 (USDA Zone).
Watering and Feeding
Centranthus ruber has moderate watering needs.
This means you have to expend a lot of energy keeping the soil moist.
Also, the plant is drought-resistant, meaning it can withstand periods of low moisture without a problem.
However, you have to be careful about overwatering.
The plant prefers dry to moderately moist soils and is at risk for crown rot if overwatered.
Soil & Transplanting
When choosing the soil for the plant, one thing to make sure of is it is well-drained.
If it’s not, excessive water can potentially lead to crown rot.
It can thrive in medium to poor soils very easily.
Sandy, loamy or chalky sand all work just fine.
You just need to maintain medium levels of moisture.
As for pH, something between mildly alkaline soil to neutral will work well.
Transplanting red valerians is not rocket science.
If you’re propagating the plant through division, the right time to transplant is in spring.
Grooming and Maintenance
Red valerian is labeled in some areas an species invasive. It needs proper care and cutting back to control self-seeds and spreading rapidly.
As for pruning, cut flower stems back after the plant has produced its first flowers during its bloom time in July.
Other than this, deadheading the flowers will encourage more blooms.
This will also prevent the plant from self-seeding and becoming a weed rather than an ornamental plant.
Established plants are drought tolerant.
How to Propagate Red Valerian
Centranthus ruber coccineus is propagated via seed.
Start sowing the seeds in late spring between February and May.
Sow them in situ or as soon as the seeds are ripe in situ.
Choose a south-facing or west-facing location and sow the seeds on the surface, just covering them.
Ensure the soil is well-drained and doesn’t dry out completely.
The seeds are likely to germinate rapidly.
Red valerian can propagate by dividing the crown during spring.
Aim your spade at the center of the bunch and divide it into half.
Gently lift one section out and transplant it where you want it to grow.
When you’re done, make sure to spread the roots of the static bunch in the space and backfill with soil.
Lastly, the plant can propagate through cutting in a cold frame during late summer.
Devil’s Beard Pest or Disease Problems
The plant is generally pest and disease-free and deer resistant.
Fortunately, these are easy to deal with.
Head to your local gardening center or nursery to find a non-toxic solution.
However, this plant is invasive.
This is why it requires special control programs focused on removing them.
Suggested Red Valerian Uses
This beautiful plant is not just pretty to look at.
Both the roots and leaves of the Red Valerian are edible.
When fresh, the leaves are often added to green salads and or lightly boiled in soups.
Some people report the leaves to have a slight bitterness.
Whether you like the flavor of the plant or not depends on your taste.
Often confused with the true valerian i.e., Valeriana officinalis, the plant is rumored to have medicinal benefits as well.
However, there is no basis for this view.
Surprisingly, some reports suggest the plant was once used in ancient times in the embalming process.
The plant looks great in cottage gardens, along stone walls, and borders.
A great pollinator plant attractive to hummingbirds.
It also provides effective ground cover when planted in groups.