Just make sure it has good soil drainage and a decent amount of sunlight. Also, aim to plant it and then leave it alone, rather than disturbing its roots by transplanting. If you wish, you can prune to encourage more flowering. But otherwise, this plant is very low-maintenance.
Light
Red campion flourishes in full to partial sunlight. When selecting its growing site, focus on an area with southern exposure where the plant can receive at least six hours of direct sunlight. If you only have a partial shade location, though, not to worry. The plant will still grow, though it might have diminished flowering.
Soil
Red campion grows best in well-draining sandy, gravelly, or loamy soils. It won’t do well in heavy clay. The ideal soil pH is neutral to slightly alkaline.
Water
This plant likes a moderate amount of water, but it can tolerate dry soil. Water young plants regularly as their root system becomes established. A good rule of thumb is to water thoroughly whenever the top 2 inches of soil have dried out. Make sure the soil is never waterlogged, as this can cause root rot.
Temperature and Humidity
Red campion does best in mild temperatures, and humidity isn’t typically a factor for its growth. Frost will kill young plants, so it’s important to be sure frost is out of the forecast before planting in the spring. Moreover, very hot temperatures can stress plants. In hot climates, it’s often best to provide them with some afternoon shade and make sure the soil doesn’t fully dry out.
Fertilizer
In general, no additional fertilizer will be necessary to grow red campion. If you have very nutrient-poor soil, you can mix some compost into the soil at the time of planting.
Types of Red Campion
There are several popular varieties of red campion, including:
‘Clifford Moor’: This Silene dioica cultivar features pink blooms with green and yellow foliage.‘Rollie’s Favorite’: This plant is known for its long bloom period. It is considered to be a hybrid plant, not a cultivar.‘Firefly’: This cultivar of Silene dioica sports rich magenta double blooms.
Pruning
Pruning isn’t essential for red campion. However, if you cut it back after the first round of flowering has wrapped up, you might get a second blooming period later in the growing season.
Propagating Red Campion
Red campion typically will self-seed easily to propagate itself. It also can be propagated by division. Not only does this get you another plant that you can grow elsewhere, but it also will help to break up overgrown clumps to restore their vigor. The best time to do this is in the spring or early fall. Here’s how: Be aware that some of the named cultivars of red campion may be trademarked and copyright protected. It is illegal to propagate these plants in any way, and doing so could lead to legal problems. ‘Clifford Moore’, for example, is a PPAF (US Plant Patent Applied For) variety, so it should not be propagated.
How to Grow Red Campion From Seed
Red campion typically germinates easily from seed sown either in the spring or early fall. Direct sow them in the garden about 1/4 inch deep and 6 to 20 inches apart. It’s best if the soil temperature is above 50 degrees Fahrenheit for spring plantings, and you should see germination within a couple of weeks. But in the fall, the soil temperature should be below roughly 45 degrees Fahrenheit (but not yet frozen), so the seeds don’t germinate until the next spring.
Potting and Repotting Red Campion
To grow red campion in containers, use a quality potting mix with sharp drainage. Select a container with drainage holes, at least 1 foot wide and deep. Unglazed clay is a good material because it will allow excess soil moisture to evaporate through its walls. Be careful not to overwater your red campion container and promptly dump any water that accumulates in a saucer if you have one. Signs that your plant needs repotting include roots coming out of the drainage holes and popping up out of the soil, as well as diminished flower production. If that’s the case, either divide your plant or move it to a slightly larger container with fresh potting soil. It’s best to do this in either the spring or early fall.
Overwintering
There’s generally no overwintering maintenance necessary for red campion. Just ensure that your planting site has good drainage. Freezing and thawing soil can become waterlogged if it doesn’t drain properly, which can damage or kill the plant’s roots.
How to Get Red Campion to Bloom
Red campion flowers grow on tall stems above the foliage. They’re only about 1 inch across, and their five petals are narrow at the base and notched at the end. They have no scent. The blooms appear in the late spring to early summer. And if you deadhead your plants, or remove the spent blooms, you can encourage further flowering. Likewise, pruning can encourage a second bloom. But even if you don’t do this, you still might get sporadic flowering throughout the summer.
Common Problems With Red Campion
Red campion rarely has problems when it’s grown in the conditions it likes. However, some issues can arise when there are environmental concerns.
Leaves Turning Yellow
Yellowing leaves is often a sign of overwatering or underwatering. And in red campion’s case, it’s more likely a sign of overwatering and/or poor soil drainage, as the plant can tolerate some drought. Make sure the soil is never waterlogged, and cut back on watering to see whether the problem resolves.
Plant Leaves Falling Off
When a young red campion plant is exposed to frost, its leaves might drop. This is why it’s crucial to plant after any danger of frost in the spring forecast has passed.
