How to Grow Rudbeckia from Seeds: Superb Summer Colour

7 August 2024 | SimplySeed

Rudbeckia or black-eyed Susans are loved for their golden flowers and low maintenance. Here’s the ultimate guide to planting, caring and choosing the best varieties for your garden.

Quick Facts

Rudbeckia like full sun, fertile, moist soil and can be planted in flower borders, beds, patios, containers and cut flower gardens.
Sow Rudbeckia seeds indoors from February to mid April or directly outside from April onwards, indoor sowing will give you earlier blooms and direct sowing will give you a natural growing season.
Caring for Rudbeckia means regular watering, mulching, feeding with the right nutrients and deadheading to encourage continuous blooming, they are low maintenance and perfect for beginners and experienced gardeners.

Where to Plant Rudbeckia

Rudbeckias love full sun so they are perfect for many garden situations. Whether you have a cottage garden, a city courtyard or a big backyard these versatile plants will thrive almost anywhere. They will grow in most soil types from heavy clay to well drained sandy soils as long as the soil is fertile and moisture retentive.

Best places to plant Rudbeckia:

Flower borders
Beds
Patios
Containers
Cut flower gardens

If you are going for a prairie style planting Rudbeckia’s robust habit and bright flowers will fit in perfectly with the landscape. Don’t forget your Rudbeckia needs full sun and well prepared soil for a show of golden flowers.

Sowing Rudbeckia Seeds

Sowing Rudbeckia seeds is fun and rewarding and can be done indoors from February to mid April or directly in the garden from April onwards. If you want to get a jump start sowing indoors will give you mid to late summer flowering. Direct sowing in the garden will give you a more hands off approach.

For Rudbeckia seeds to germinate they need light and moisture when sowing. Here’s what to do:

Cover the seeds lightly with soil or press them into the surface.
Provide light and moisture.
Germination takes 14 to 21 days. Whether you sow indoors or outside following these steps will give you Rudbeckia with daisy like flowers.

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Indoor Sowing

To sow Rudbeckia seeds indoors:

Use seed trays or small pots with a sterile seed starting mix.
Sow the seeds 6 to 8 weeks before the last frost date.
Cover the seeds with a thin layer of soil.
Keep the growing medium moist.
Control soil temperature and moisture which is crucial for germination.

To grow Rudbeckia seedlings:

Place the trays on a bright warm windowsill, ideally at 18 to 22 °C.
Cover the trays with a clear plastic bag to retain humidity and create a seedling environment.
Follow these steps and your Rudbeckia seedlings will be ready to transplant into the garden when the frost has gone.

Direct Sowing

Direct sowing Rudbeckia seeds in the garden can be done in early spring once the frost has gone and the soil has warmed up. Here’s how:

Use poor garden soil for best results as Rudbeckias love that.
Sow the seeds evenly.
Cover with a thin layer of soil.
Water gently to start germination.

Make sure the seeds get light and moisture to sprout in 2 to 3 weeks. This method is perfect for naturalising in your flower bed or filling large areas with golden flowers. With a little care your Rudbeckia seeds will grow into robust plants and brighten up your garden.

Planting Young Rudbeckia

Best time to plant young Rudbeckia is during frost free periods. This can be done in late autumn or from March onwards. Here’s how:

Loosen the soil to a depth of about 1 spade.
Add mature compost or organic matter if you have heavy clay or sandy soil.
Doing this will give you a fertile and well draining soil which is essential for the plants health.

When planting in beds space the seedlings 30 cm apart to avoid overcrowding and give them room to grow. If using containers make sure they are at least 20 to 30 liters and have a drainage layer. Plant at the same soil level as the original pot and water well after planting and the young plants will establish quickly.

Buying young plants from a garden centre or nursery is an option if you don’t want to start from seeds. After transplanting keep the soil consistently moist and apply a balanced fertilizer to promote growth. With a little care your Rudbeckia will flourish and give you masses of flowers all season.

Caring for Rudbeckia all season

Rudbeckias are low maintenance so are perfect for both beginners and experienced gardeners. Their long flowering season is from late summer to autumn and gives you continuous colour in your garden. Regular care is to cut the plants back to about 10 cm in autumn to prepare them for next season.

Perennial Rudbeckias like Rudbeckia fulgida will look attractive throughout the winter with their stems and seedheads providing food for birds and shelter for wildlife. Not only will this keep your garden looking good but also the local biodiversity. Follow these simple care tips and you can enjoy Rudbeckia every year.

Watering and Mulching

Water regularly to keep the soil moist especially during dry periods. Rudbeckias like moist soil so water them deeply and regularly. Mulching around the plants will help retain moisture and suppress weeds and reduce maintenance.

Apply a thin layer of organic mulch like compost or straw around the base of the plants. This will conserve moisture and improve soil fertility as it breaks down. Keep your Rudbeckia plants watered and mulched and they will grow and flower all season.

Feeding and Fertilising

Feeding Rudbeckia the right nutrients is important for good growth and flowering. Start by applying a general granular plant food around the plants and water in well. Follow up with a 5-7.5 cm thick layer of organic matter to top dress the soil.

A slow release fertiliser applied in spring will give season long feeding and supplementing with liquid plant food every few weeks during the growing season will give a growth and flowering boost. Follow these feeding tips and your Rudbeckia will thrive and give you healthy and vibrant flowers.

Pruning and Deadheading Rudbeckia

Pruning and deadheading Rudbeckia in your cut flower garden is a must to get continuous flowering and a tidy look. Regularly removing the faded flowers will encourage the plants to produce more. For single flower per stem Rudbeckias cut the stem back to the base of the plant when deadheading.

For multiple flowers per stem Rudbeckias snip off the spent blooms individually to keep the plant looking neat and tidy all season. Follow these simple care tips and you’ll have a garden full of colourful and healthy Rudbeckia.

Propagating Rudbeckia

Rudbeckia can be propagated by seeds, division or rhizome tubers, division is the most reliable method. The best time to divide Rudbeckia is from mid February to end of March when new shoots start to appear in early spring.

To propagate Rudbeckia by division:

Dig up the plant.
Separate the roots into smaller sections, each with healthy roots and shoots.
Plant the divisions straight away into well prepared soil.
Water in well.

This will help you increase your Rudbeckia collection and keep your plants healthy.

Common Problems and Solutions

Slugs and snails are common pests that will damage young Rudbeckia plants, leaving shiny trails and chewed leaves behind. They can devour an entire bed of seedlings overnight so early action is key.

Handpicking slugs and snails at night or early morning is a good control method. Setting up beer traps will also catch these pests and reduce their numbers and protect your plants. Be vigilant and follow these methods and your Rudbeckia will be healthy and happy.

Rudbeckia Varieties

Rudbeckia, also known as coneflowers or black-eyed Susans. They come in annual, biennial and perennial forms, each with different colours and characteristics. Popular varieties include Rudbeckia fulgida with bright yellow petals and dark central cones, Rudbeckia hirta often called black eyed susan with russet, dark red or brown flowers and Rudbeckia triloba another species in the Rudbeckia family.

Annuals like those from Suttons will give vibrant colours from late summer to autumn, perennials are long lived and will give robust blooms. Rudbeckia foliage can be hairy or smooth adding texture to any garden design.

Rudbeckia Hirta Varieties

Rudbeckia hirta ‘Cappuccino’ is an annual with burnt orange petals and dark brown markings, grows up to 60cm tall. Cherokee Sunset is another popular one with sunset shades and dark centre, great for cut flower gardens.

‘Prairie Sun’ has yellow flowers with pale green centre and two tone petals, will brighten up any garden space. These are perfect for gardeners who want vibrant, showy blooms that will thrive in full sun and are also good for cut flower arrangements.

Perennial Rudbeckia Varieties

Among the perennial Rudbeckia varieties Rudbeckia fulgida var. sullivantii ‘Goldsturm’ is the standout with dark green foliage, rich yellow flowers and black pincushion heads. It also has a good winter silhouette so is a great addition to any garden.

Rudbeckia fulgida var. deamii is another popular perennial with open branched structure, rough hairy stems and clear yellow petals. It’s also slug resistant so another bonus. Both are good choices for gardeners who want reliable long lasting blooms.

Companion Planting with Rudbeckia

Companion planting with Rudbeckia will add to the visual interest and biodiversity of your garden. Plant with:

Aster
Helenium
Sedum
Salvia

and you’ll have a colourful and dynamic display. Hyssop’s medium blue looks great with Rudbeckia’s orangey yellow and adds a nice colour contrast.

Herbs like Phlox, Geranium and Delphinium will give a staggered flowering effect so you’ll have blooms all season. Grasses like Miscanthus and Pennisetum will add movement and structure and will sit well with Rudbeckia’s upright habit and bedding plants.

Rudbeckia in Different Garden Styles

Rudbeckia’s versatility means it can be used in:

Cottage and informal gardens
Modern urban spaces
Borders
Summer bedding
Tubs & Planters
Prairie style gardens

Their sturdy upright stems and daisy like flowers will fit in with these different styles.

In urban gardens Rudbeckia will bring a bit of nature into your space, they will thrive in containers and small spaces. Their vibrant colours and low maintenance makes them perfect for adding colour and life to any garden. Use Rudbeckia in different styles and you’ll have a fabulous and diverse outdoor space.

Conclusion

Growing Rudbeckia is fun, with vibrant long lasting blooms and low maintenance. From choosing the right spot to sow and propagate we’ve covered it all.

Follow these tips and you’ll have a garden full of Rudbeckia flowers. Whether annual or perennial you’ll love seeing those golden blooms in your garden. Enjoy Rudbeckia and watch your garden come alive with colour.

FAQs

When should I sow Rudbeckia seeds?

Sow Rudbeckia seeds indoors between February and mid April for mid to late summer flowering. You can also sow directly in the garden from April when the soil has warmed up.

How far apart do I plant Rudbeckia seedlings?

When planting Rudbeckia seedlings space them 30 cm apart to avoid overcrowding.

What are the common pests that affect Rudbeckia and how do I control them?

To control pests on Rudbeckia like slugs and snails hand pick them at night or early morning and use beer traps to catch them. This will reduce the damage.

How often do I water Rudbeckia?

Water Rudbeckia regularly to keep the soil moist especially during dry spells. Mulch will help retain moisture and reduce the need to water so often.

Can I grow Rudbeckia in tubs & planters?

Yes Rudbeckia can be grown in planters with at least 20-30L and drainage.