How to grow and care for wallflowers

Last updated on March 29th, 2022

Wallflowers provide flowers throughout the spring and summer, perfect for adding an array of colours to your garden beds, borders, or containers. Their flexibility makes it easy to grow them wherever you have space available. What’s more, you can grow them as annuals, biennials (those which grow during the first year and subsequently flower during the second year), or as perennials. 

Wallflowers are quintessential bedding plants that are overrun with flowers in spring, like Erysimum Cheiri, or they can be planted as a more permanent perennial that flowers in the spring and summer and even in winter, although they do become woody after a year or two. They do respond well to hard pruning and one of our personal favourites is the Erysimum ‘Bowles Mauve’.

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Where to Plant

Before you start growing your wallflowers from seeds, planting bare root wallflowers, or potted perennials, not forgetting the annuals you buy in bedding trays, figure out where you want to plant them. There are many varieties that make delightful backdrops to a garden bed or line central garden paths in cottage themed gardens. The smell, as you make your way through the wallflower area, will prove well worth the effort. 

The most successful cultivation will include at least 15 plants of different types, intermixed. This gives more variety and aesthetic appeal to the garden.

Make sure, too, that you know what it is you plan to sow. Given space, the colours, and the scents, you need to make sure your intended space can accommodate the plants. Some have large, straight stems that grow quite tall while others are smaller. You can find biennials, perennials, or annuals, depending on what you want to get out of the design. 

Learn how to grow wallflowers from seed in this guide

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How to Grow Wallflowers

Choose a sunny location

If you plan to grow wallflowers in a garden bed, you can grow them in full sun. This will generate the best results. You can find a few that tolerate light shade if there are no fully sunny areas in your garden. 

Many wallflowers are flexible in that they tolerate poor soils, so even bad soil won’t need to be severely altered, with the exception of making sure it’s free-draining by mixing some grit into the soil.

Mix plenty of organic matter and grit into the soil to improve drainage

In order to generate the best floral production, you should use fertile soil with organic matter to improve drainage. Like most plants, they do not appreciate being waterlogged nor do they appreciate drying out too quickly. That is why having a soil mixture perfectly able to retain lots of moisture is best and this is where mixing plenty of organic matter and grit comes in. 

Before you add your new wallflowers to your garden, mix a high potash granular fertiliser into the soil. 

If you are growing perennial wallflowers though, they need full sun with neutral or alkaline soil. 

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When to plant Wallflowers

Growing from seeds

When sowing from seed, you want to plant between May and July outdoors. You can choose a well-drained, sunny spot and sow the seeds directly into the ground. Place them around 13mm deep in rows that are 30cm apart. The seeds should be covered with fine soil and then watered well immediately after sowing. 

During the dry periods, you need to water more frequently than normal. Again, the wallflowers should be allowed to dry out. 

If you are not ready to put them in their final position, you can grow them elsewhere in the garden and then transplant them when they are large enough. Alternatively, you can sow them indoors with seed trays a little earlier than you would plant them outdoors which means they usually flower a little sooner. 

Sowing seeds indoors

For indoor sowing, make sure the temperatures remain around 13-15°C. Place the seed tray inside a propagator or plastic bag and seal it to create a miniature greenhouse. Again, once they are large enough to be moved, you can bring them outdoors and transplant them into individual pots or in your garden. It is recommended that if you propagate from seed, you move them multiple times into other containers and pots, each slightly larger than the last until they are moved into their final position in the garden. 

When they are young, around 12cm tall, you can pinch the top, or apex stem to force them to bush outwards. It will take some time, even as long as a few years for the taller types, to reach their ultimate height which ranges between 30cm and 75cm. At full maturity, they spread between 20cm and 90cm.

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When to Plant Outdoors

When you have plants you have sown from seed, you can move them outdoors between September and October, planting them around 30cm apart. 

If you have perennial wallflowers, they can be planted at any time but do best when planted in spring.

If you buy trays of bedding wallflowers, these can be planted straight away.

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How to care for Wallflowers

Feeding

Once they are in the garden, you must keep the soil moist. Liquid feeds, administered regularly during the flowering period will help prolong it. As the wallflowers begin to produce flowers, you can deadhead them to extend the flowering period too. 

At the end of the flowering period, you can cut back your perennial varieties so that they remain compact. Giving them a liquid feed can, for some, encourage an additional flush of flowers in autumn. 

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Diseases

Be on the lookout for clubroot disease. This is the biggest threat to wallflowers but can be treated with commercial products.

Last update on 2024-11-23 / Affiliate links / Images from Amazon Product Advertising API