Centranthus Plant Growing & Care Guide for Gardeners

Article by Dean Ravenscroft, Ph.D. - Updated 22nd Nov 2023

In this Gardener's HQ guide, we'll explore cultivating Centranthus plants in your garden, indoor spaces, and other settings.

Red Valerian, and Jupiter's Beard: Cultivation & Garden Use

Centranthus genus plants are shrubby hardy perennials that reach between 70 and 90 cm (30 to 36 inches) in height.

Some of the common names for Centranthus plants include Jupiter's beard, Petty Betsy, Valerian, and Keys of heaven.

They flower from the late spring, with blooms of white or pink flowers

Their size makes them ideal for rockeries, or to fill the gaps in walls.

Centranthus (Red valerian) by Matthew Hillier.

Centranthus ruber by Captain Mish.

How to Grow Centranthus

Centranthus plants should be sown outdoors in the early spring before the last frost. Once sown the seeds should be lightly covered.

They should ideally be grown in sunny parts of the garden. Ideally locate in limy soils which have good drainage.

If you first plan to grow seedlings of Jupiter's beard and other Centranthus species indoors, then you should start the process about eight weeks before you plan to transplant them into the garden. Ideally after the last frost of spring.

They require about three or four weeks to germinate at a temperature of about 18 degrees celsius (64°F).

When planting the seedlings out, they should be spaced at about 30 to 45 cm (12 to 18 inches) apart.

Caring for Centranthus in the Garden

Centranthus plants should be lightly fertilised in the spring.

Once the first flowers have finished blooming, cutting them off will often result in a second bloom.

At the end of the autumn, the plants inflorescence stems should be cut back to the ground.

Common Questions

How many members does the Centranthus genus have?

The Centranthus genus contains about 12 species.

Do members of Centranthus make a good garden or landscaping plant?

Yes, particularly Centranthus ruber (Red Valerian), known for its pretty clusters of red, pink, or white flowers and resilience.

Which Centranthus species are most frequently grown by gardeners?

Centranthus ruber (Red Valerian) is commonly grown due to its showy blooms and easy care.

Are members of the Centranthus plant genus fragrant?

While not overwhelmingly fragrant, Centranthus plants have a subtle, sweet scent that is most noticeable in the evening.

What is the perfect location to grow Centranthus?

Centranthus thrives in full sun to partial shade and prefers well-drained soil. It tolerates poor soil and drought, making it a good choice for challenging spots.

Is Centranthus invasive in the USA?

Centranthus ruber (Red Valerian) is currently considered invasive in parts of California due to its ability to self-seed aggressively.

How do I remove Centranthus plants from my garden?

To control Centranthus, remove the plants before they seed. Pull up any new seedlings as soon as they appear.

Summary

The Centranthus genus, part of the Caprifoliaceae family, originates from the Mediterranean region. One of the most recognized species, Centranthus ruber or red valerian, is a perennial herb known for its clusters of small, vibrant flowers that bloom in summer.

To cultivate Centranthus, plant them in full sun to partial shade, in well-drained soil. They are very hardy and can tolerate poor soil conditions. Plant in the spring or fall, and ensure regular watering during dry periods. Once established, they require minimal care and can self-seed extensively if not controlled.

I hope that you found this guide on how to grow Centranthus plants in your garden. You may also enjoy my gardening guides on how to grow Weigela florida Alexandra, Scabiosa plant, and Patrinia plants.