How to Grow Centranthus Ruber (Red Valerian)

Cetranthus Ruber (also commonly known as Red Valerian) is a hardy perennial that adds a wonderful splash of vivid color in any garden. The cut flowers also look great in a bouquet.

Easy to grow and low-maintenance, it produces an abundance of star-shaped flowers that have an impressively long bloom time. It's a great choice for cottage gardens as it'll grow in the cracks of chalky walls and pavers. It also works well in wildflower areas.

Red Valerian has a strong, sweet fragrance, and pollinators can't resist this flower. Plus, with its deep roots, it works well on slopes to help prevent soil erosion.

How to Grow Centranthus Ruber

Providing your Red Valerian gets plenty of sun, you won't have to worry about any complicated or high-maintenance growing requirements.

This hardy plant is tolerant of poor, infertile soils and dry conditions. It's also easy to grow from seeds, root divisions and cuttings.

Light

Red Valerian does best in a full sun position. It can tolerate partial shade too, but it may not produce quite as impressive a bloom through the summer.

Soil

If you're looking for a plant that will thrive despite poor soil conditions, Centranthus Ruber would be a good choice. It copes with dry, infertile soils incredibly well and will flourish in a compact form in areas where many other plants die off.

It does prefer a slightly alkaline soil type. Limestone can be added to create better growth conditions if your soil is more on the acidic side. If the soil you're planting in is a richer variety, you may find that the tall Red Valerian will benefit from staking.

Water

A drought-tolerant plant, Red Valerian doesn't need a lot of water. Young seedlings will need light watering, but established plants can cope fine with natural rainfall alone. This plant doesn't tolerate over-watering well. The only time you'll need to water a mature specimen is if there has been a prolonged very hot spell and the soil is excessively dry.

Temperature and Humidity

Overly hot and humid summers are one thing Centranthus Ruber isn't a fan of.

Fertilizer

As you would expect with a plant that copes well in infertile soils, you won't need to fertilize your Centranthus Ruber.

Pruning

Red Valerian self-seeds readily, and cutting it back drastically after the bloom period can help to control any unwanted spread. It also means the bloom will be more abundant the following year. Often blooming from early summer all the way through to September, don't be tempted to cut back the flowers too early.

Harvesting

The young, fresh leaves of Centranthus Ruber can be used in salads and added to soups. It's also possible to cook the root for eating too. Opinions differ on whether this is a good idea, however, as the leaves have a definite acquired taste. Many people claim they're overly bitter.

Propagating Centranthus Ruber

Basal cuttings can be taken in the spring or early summer, or you can divide the roots in spring or fall to produce new plants.

Division every few years is recommended as this prevents the central section of clumps from dying off, and it stops the root system from becoming overcrowded.

Growing From Seeds

Growing Centranthus Ruber from seed produces good results. If you plan to sow during the winter, you should pick a sheltered spot, keep the soil slightly moist, and it's best to use a tray that can be covered to protect the seeds from any hard frost.

The seedlings can be transplanted into the ground when the temperatures rise, usually around May time. Red Valerian seeds germinate rapidly when temperatures are above 68°F.

Sowing directly into the ground in spring is also possible. As the first leaves appear, it's a good idea to thin them out, selecting the most vigorous seedlings to keep. Make sure you water the seedlings regularly, but only enough to keep the soil mildly moist.