Erysimum, commonly referred to as wallflowers, can be perennial, biennial, or annual plants. With their diverse characteristics, these flowers thrive in various environments. These attractive flowers are a firm favourite with many gardeners, who find that they will grow well and self seed in a range of different garden settings.
A polytunnel can help you to keep these biennial plants safe and happy throughout the year, whether you decide to give them some final growing space within the polytunnel or elsewhere in your garden.
The most commonly cultivated wallflowers are biennials, often referred to as bedding wallflowers. These varieties are typically propagated from seeds, although plug plants are also available for purchase.
Perennial wallflowers are gaining popularity as well. These are commonly bought as potted plants. Unlike biennials, perennial wallflowers are sterile and cannot be grown from seeds. Therefore, propagation is achieved through cuttings. Perennial wallflowers serve as an excellent nectar source, offering a consistent and extended supply of food for pollinators throughout the season.
Please see the table below to learn when to sow wallflower seeds, when to plant wallflowers, and when do wallflowers flower throughout the year in the UK.
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Wallflowers are pretty hardy, thriving in well-drained soil and full sun, although they can also adapt to partial shade conditions. Wallflowers are a plant that thrives, to a degree, on neglect. They will grow best in a well-drained soil that is not particularly fertile. An alkaline or neutral pH is ideal.
Wallflowers are actually incredibly easy to grow, as long as you understand what they need and their attractive blooms come in a wide range of different shades. Wallflowers are a pretty and delicate addition to your garden, whether you grow them in containers, in the polytunnel or in a sunny border.
Cultivate wallflowers in soil that is moist yet well-drained, ideally in an area receiving full sun to partial shade.
You might grow wallflowers among other flowering plants in an ornamental display or in a mixed planting scheme alongside some edibles. Where space is limited, wallflowers might be grown in containers, as well as in raised beds, or in the ground in a border.
To grow biennial bedding wallflowers from seeds, follow these steps:
Sow wallflower seeds during the spring months (March-May).
Plant the seeds into a seed tray filled with suitable seed starting potting mix.
Place the tray in a cool, sheltered location to facilitate germination.
After 4-5 weeks, carefully transplant the seedlings into their own individual containers.
Once the plants are well-established, either plant them out into the garden in autumn or wait until the following spring for transplantation.
Anticipate that these biennial spring bedding plants will bloom in the spring, approximately one year after sowing the seeds.
Plant out in autumn or the spring that follows. It can be beneficial to add a handful of grit to the planting hole where the soil is heavier to improve the drainage.
Biennial wallflowers complement spring blooms beautifully when paired together. Planting young wallflower plants alongside bulbs in containers during autumn ensures a vibrant spring display.
To achieve optimal results, space the wallflower plants approximately 15cm apart in the container, and plant them simultaneously with tulip bulbs. This coordinated planting approach yields a stunning and harmonious arrangement in the springtime.
You might also combine with other spring-flowering bulbs in a 'bulb lasagna'.
One of the key things to remember about wallflowers is that, as biennials, they will have to be sown and grown the year before they are to flower. Seeds can be sown in the early summer, in a well prepared seed bed or in trays. However, many people choose to start from wallflower plugs, which can be bought in late summer or early autumn from garden centres or plant nurseries and planted out in November.
Biennial, bedding Wallflowers typically bloom from early spring, with the possibility of flowering as early as March. The blooming period then extends through the midsummer months. Perennial wallflowers can bloom right through from spring to the following winter and almost year-round in southern regions.
Wallflowers are exquisite flowers with four-petaled blooms available in a vibrant array of colours, including yellow, orange, red, blue, and purple. Notably, they emit a delightful, sweet fragrance, enhancing their allure in any garden or floral arrangement.
Encourage a profusion of blooms by periodically pruning back the plant. Ensure that the wallflowers are positioned in an area with ample sunlight, as this fosters optimal growth and flowering. Avoid fertilization, as this can stimulate excessive foliage growth at the expense of flower production. Instead, allow the plant to naturally prioritize flower production, resulting in a more abundant and vibrant display of blossoms.
Biennial, bedding wallflowers are discarded after flowering. But perennial types will live on and can remain in your garden if properly cared for over several years.
The most important part of caring for wallflowers is placement. Remember that a full sun position with free-draining soil is required.
Water newly planted wallflowers thoroughly to help establish their roots in the soil. During extended dry spells, and of course if growing undercover, provide water to ensure the plants remain adequately hydrated.
Keep a vigilant watch on wallflowers grown in containers, as they may require more frequent watering compared to those planted in the ground due to the limited soil volume. Maintaining consistent moisture levels is key to promoting healthy growth and prolific blooming in wallflowers.
You do not need to feed wallflowers and in fact, doing so may be counterproductive. Mulching newly planted wallflowers can be beneficial, however, to conserve soil moisture and suppress weed growth to a degree.
It is important to remember that some wallflowers will grow much taller than others. Some of the taller varieties can be more prone to drooping or being blown over in windy conditions and can also develop a lean.
When cultivating a block of wallflowers, consider using jute netting or similar to provide support. Spread the netting horizontally across the entire block, securing it to canes at each corner.
Ensure the netting is stretched taut over the plants, maintaining a height of approximately 20cm (8in). This method promotes upright growth in wallflowers, and as the foliage expands, it will naturally cover the netting, resulting in a visually pleasing display.
When the flowers on the plants wither, it's essential to remove them promptly. Trim the stems to prevent them from protruding above the foliage. Removing spent blooms often stimulates additional flowering throughout the season.
However, it's important to note that some varieties of wallflowers readily self-seed. If you desire this, allow the faded flowers to remain on the plant until the seeds mature and disperse.
For gardening enthusiasts interested in cultivating perennial Erysimum, there's encouraging news: these plants can be easily propagated from cuttings. The ideal time on when to cut back wallflowers is in the spring, preferably between May and June, extending up to July. Here's a step-by-step guide to carry out this straightforward gardening task:
Choose a robust, non-flowering shoot from your perennial Erysimum.
Carefully cut a portion of the shoot to use as a cutting.
Remove all lower leaves from the cutting.
Optionally, dip the end of the cutting in rooting hormone to encourage root development.
Pot up your cuttings and await the rooting process.
Cultivate your cuttings in individual pots for optimal growth.
Once they are well established, transplant them into the desired outdoor location.
To promote the development of bushier and more compact forms in bedding wallflowers, it is advisable to gently pinch off the tips of the plants while they are still young. This practice helps prevent them from growing leggy and encourages a more aesthetically pleasing shape. Erysimum, commonly known as wallflowers, are excellent choices for cut flowers, allowing you to gather blooms for indoor floral arrangements before they start to fade. Trim the stems as needed, ensuring to cut back to the foliage to maintain the plant's appearance.
Bedding Erysimum are typically discarded after the flowering period, while perennial types can beautify your garden for several years with proper care. Pruning can help maintain the appearance and longevity of perennial Erysimum, such as the popular 'Bowles Mauve', which may become leggy over time. Lightly prune these plants in autumn, ideally between September and November, taking care not to cut into older, woodier growth.
Trim just a few centimetres, no more than 5cm, of top growth each year, as these plants do not tolerate heavy pruning well. After pruning, mulch generously with organic matter to help the plants overwinter successfully, ensuring robust regrowth and flowering in the following season.
Some biennial and perennial wallflowers to consider are:
Erysimum cheiri 'Sunset Primrose' (Sunset Series) (AGM)
Erysimum cheiri ' Persian Carpet' (AGM)
Erysimum 'Ivory White'
Erysimum 'Winter Orchid' (Winter Series)
Erysimum 'Winter Passion' (Winter Series)
'Bowles Mauve' (AGM)
'Constant Cheer'
'Artist's Paintbox'
Wallflowers belong to the brassica family, which makes them susceptible to diseases like club root and other ailments common to this plant family. Issues such as downy mildew, leaf blight, and flea beetle infestations can arise, so it's important to remain vigilant. Additionally, watch out for damage from slugs and snails, especially on young plants.
Perennial wallflowers have a relatively short lifespan and may become woody over time. To mitigate potential losses, it's advisable to take cuttings annually. This practice helps ensure a continuous supply of healthy plants and guards against any decline in the vigour of the existing ones.
One pest that can arise is flea beetle. Flea beetles are tiny, shiny, black insects resembling pinheads, and they move about by hopping, much like fleas.
You'll notice their presence on your wallflowers if the leaves are peppered with small holes. While mature plants can usually withstand their feeding, young seedlings are more vulnerable. Although the holes they create are not typically lethal to young wallflower plants, they can significantly delay their growth by several weeks.
To address flea beetle infestations, one of the best approaches is to companion plant with mustard plants, which naturally attract flea beetles away from the wallflowers, serving as a trap crop and helping to protect them from damage.
A polytunnel can be a valuable asset in maintaining the health and vitality of biennial wallflowers throughout the year, whether you opt to provide them with additional growing space within the polytunnel or elsewhere in your garden. Wallflowers are remarkably uncomplicated to cultivate, provided you meet their basic requirements, and their charming blooms come in a diverse array of shades.
These lovely and delicate flowers make for a delightful addition to any garden setting, whether planted in containers, nestled within a polytunnel, or gracing a sunlit border. With their versatility and beauty, wallflowers can enhance the aesthetic appeal of your garden.
