How to grow Rudbeckia

Choosing rudbeckias

The popularity of this genus is well deserved; it is easy to grow, lends itself to different planting styles, flowers for a long time, and is good for wildlife.

When selecting the right one for your garden, bear in mind the following:

• Most species grown in the UK are hardy herbaceous perennials. The main exception is R. hirta which is very short lived and not reliably hardy, so it is usually grown as an annual from seed
• If you want to grow an annual for summer bedding, cut flowers, containers or for borders, choose a cultivar
  

  Gardeners often use the word variety when referring to a specific plant, but the correct botanical term is 'cultivar'. Whichever word you use, it means a distinctive plant or plants, given a specific cultivar name and usually bred to enhance certain characteristics, such as flower or fruit size, colour, flavour or fragrance, plant size, hardiness, disease resistance, etc. Additionally, it is worth knowing that, botanically, variety has another meaning - it refers to a naturally-occurring distinct plant that only has slight differences in its looks. For example, Malva alcea var. fastigiata differs from typical plants by having an upright habit.

  of R. hirta
• Rudbeckias vary a lot in size. R. hirta ‘Toto’ reaches about 25cm (10in), whereas R. laciniata can grow to 3m (10ft). Tall types will benefit from staking or shortening using the pruning technique of the Chelsea chop
• Most rudbeckias grow in easily manageable clumps, but R. laciniata has vigorous rhizomes
  

  Rhizomes are creeping swollen root-like structures that are actually adapted stems. Roots, stems with leaves and flowers are produced along its length. See plants such as Anemone nemorosa, bamboo, canna, border iris.

  (horizontal underground stems) that make it better suited to larger gardens else you'll need to lift and divide clumps regularly to keep them in check
• All types like a sunny spot and they will struggle if the soil dries out in the growing season
  

  The period of time when an individual plant is in active growth. This will depend on the local climate and light levels, and can vary between different plants, although it is broadly from spring to autumn.

  . R. hirta and R. fulgida var. deamii are slightly more tolerant than most of dry conditions
• Although they like a moisture retentive soil, rudbeckias don’t like prolonged periods of wet soil in winter. R. maxima and R. subtomentosa are more able than most to withstand wet conditions
• Choose rubeckias that have received the RHS Award of Garden Merit, as these have been assessed and are known to perform well

RHS hardiness rating

Buying rudbeckias

Buy seeds for annual and perennial

Perennials are plants that live for multiple years. They come in all shapes and sizes and fill our gardens with colourful flowers and ornamental foliage. Many are hardy and can survive outdoors all year round, while less hardy types need protection over winter. The term herbaceous perennial is used to describe long-lived plants without a permanent woody structure (they die back to ground level each autumn), distinguishing them from trees, shrubs and sub-shrubs.

Rudbeckia from garden centres and online seed catalogues (eg. Chiltern Seeds, Thompson & Morgan).

Buy small plug plants

Seedlings or young plants grown singly in small modules, with the advantage that they can be transplanted with minimal root disturbance. Bedding plants and young veg plants are often sold as plug plants of various sizes, with smaller ones requiring more aftercare. They usually need to be potted up and grown on indoors until large enough to plant outside.

in spring from garden centres or by mail order. You will need to pot plug plants into larger 9cm (3½in) pots and harden them off (process of toughening them up so they can cope with outdoor temperatures) before planting out after the frosts (typically late May/early June).

Many garden centres and nurseries stock rudbeckias. Use our Find a Plant Tool for stockists.

You will most likely see container-grown rudbeckias for sale, but it is possible to buy herbaceous perennials as bare-root

These have been lifted from the ground while dormant, with little or no soil around their roots. Various plants may be available bare root, including fruit trees, hedging plants and some perennials. They are generally cheaper than plants in containers, but are only available in winter/early spring, while dormant

plants. These will be available by mail order from autumn through to early spring. Buying bare-root plants is a good way to avoid the use of new plastic pots (see 'When to plant' section below).

Buying: garden centre plants

Buying: mail order plants

How to choose healthy plants

When to plant

• Annual rudbeckias will need hardening them off (process of toughening them up so they can cope with outdoor temperatures) before planting out after the frosts (typically late May/early June).
• Perennial
  

  Perennials are plants that live for multiple years. They come in all shapes and sizes and fill our gardens with colourful flowers and ornamental foliage. Many are hardy and can survive outdoors all year round, while less hardy types need protection over winter. The term herbaceous perennial is used to describe long-lived plants without a permanent woody structure (they die back to ground level each autumn), distinguishing them from trees, shrubs and sub-shrubs.

  rudbeckias are best planted in spring (March to early May) while the ground is moist.

Container-grownperennial rudbeckias are sold throughout the year at garden centres and nurseries. Plant at any time as long as the ground is not frozen or waterlogged

Describes soil or potting compost that is saturated with water. The water displaces air from the spaces between soil particles and plant roots can literally drown, unless they are adapted to growing in waterlogged conditions. Waterlogging is common on poorly drained soil or when heavy soil is compacted.

. If you plant in summer, they will require additional watering to keep the soil around the roots moist.

Plant bare-root

These have been lifted from the ground while dormant, with little or no soil around their roots. Various plants may be available bare root, including fruit trees, hedging plants and some perennials. They are generally cheaper than plants in containers, but are only available in winter/early spring, while dormant

perennial rudbeckias soon after delivery. If weather conditions are not favourable for planting it is important to ensure that the roots don’t dry out; you can stand the roots in a bucket of moist compost

Can refer to either home-made garden compost or seed/potting compost:

• Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

, or lay them diagonally in a shallow trench and back-fill with soil to cover the roots (heeling-in). Plant out as soon as weather conditions improve.

Where to plant

Rudbeckias grow well in full sun. They will flower okay in light shade, but the shadier the location the less they will flower.

Rudbeckias like a fertile soil that holds plenty of moisture in spring and summer. They don’t like to dry out, mulch

Mulch is a layer of material, at least 5cm (2in) thick, applied to the soil surface in late autumn to late winter (Nov-Feb). It is used to provide frost protection, improve plant growth by adding nutrients or increasing organic matter content, reducing water loss from the soil, for decorative purposes and suppressing weeds. Examples include well-rotted garden compost and manure, chipped bark, gravel, grit and slate chippings.

with well-rotted organic matter after planting and every spring to help retain moisture around the roots.

Rudbeckias originate from the prairies of North America, so they are able to grow well in exposed windy areas. They also grow happily in sheltered conditions.

How to plant

Rudbeckias are easy to plant, see our guide to planting perennials:

Perennials: planting

Watering

Rudbeckias in borders

Water well after planting. On free-draining soil or during prolonged dry spells, they will need additional water to keep the soil around the roots slightly moist, but not soggy. Aim to water well and occasionally, rather than little and often.

Rudbeckias in containers

These need more frequent watering than plants growing in the ground. Water as often as needed, which could be daily in hot weather. Try not to let the compost

Can refer to either home-made garden compost or seed/potting compost:

• Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

dry out, but don’t let it get waterlogged

Describes soil or potting compost that is saturated with water. The water displaces air from the spaces between soil particles and plant roots can literally drown, unless they are adapted to growing in waterlogged conditions. Waterlogging is common on poorly drained soil or when heavy soil is compacted.

either.

Watering

Feeding

Rudbeckia need little or no regular applications of fertiliser in most garden soils. Mulching plants in borders with well-rotted manure or garden compost each spring should be sufficient. If your garden soil is light and sandy, feed your Rudbeckia plants in spring when they start to come into growth with a general-purpose fertiliser such as Growmore, applying a handful per sq. m/yd.

For containers, use a liquid fertiliser, such as Phostrogen or seaweed feed, diluting according to the instructions on the bottle.

Deadheading

If you deadhead when flowers have faded this will encourage plants to keep flowering. To get the maximum amount of flowers from Rudbeckia grown as summer annuals

Annuals are plants that complete their life cycle in one growing season. They are generally easy to grow from seed or can be bought as young plants from garden centres. Annuals are ideal for growing in summer containers and filling gaps in borders. Some examples of annuals include sunflowers, cosmos, sweet peas and zinnia.

, it is definitely worth regularly deadheading

Deadheading is the process of removing spent flowers from plants to encourage more blooms and prevent seed production. This helps to redirect the plant's energy into producing more flowers rather than producing seeds.

. You might choose to leave the seedheads for winter interest. Cones of Rudbeckia seedheads from perennials look attractive during the winter and provide food for birds.

Deadheading plants

Overwintering

Hardy rudbeckias grown in open ground should not need any protection.

Cultivars of Rudbeckia hirta may survive some winters in relatively mild parts of the UK, but in most gardens they will struggle to get through the winter. Cultivars of R. hirta are usually grown as annuals and composted in late autumn, but because they are short-lived perennials they could be overwintered in a light, frost-free environment (such as a frost-free greenhouse) and planted outside the following May/June.

Caring for older plants

Some of the tall species need staking. Alternatively, you can Chelsea chop tall Rudbeckia in May to reduce the eventual height and do away with the need for staking.

Perennials: staking

Chelsea chop

Like many herbaceous perennials, rudbeckias benefit from being lifted and divided every three to five years to maintain health and vigour. Lift and divide rudbeckias in early spring (March/April).

R. laciniata is vigorous and spreads by rhizomes

Rhizomes are creeping swollen root-like structures that are actually adapted stems. Roots, stems with leaves and flowers are produced along its length. See plants such as Anemone nemorosa, bamboo, canna, border iris.

; therefore, it might need lifting, dividing and reducing every two to three years to keep it in check.

Perennials: dividing

From division

Three to five years after planting a Rudbeckia, it will be ready to be dug up and divided into smaller clumps. This is an easy way to make more plants.

Perennials: dividing

From seed

Rudbeckia can be propagated from seed; this is particularly useful for raising cultivars of R. hirta that are often used as annuals

Annuals are plants that complete their life cycle in one growing season. They are generally easy to grow from seed or can be bought as young plants from garden centres. Annuals are ideal for growing in summer containers and filling gaps in borders. Some examples of annuals include sunflowers, cosmos, sweet peas and zinnia.

.

Sow indoors in early spring (March/April) in trays containing moist, peat-free seed compost

Seed compost is a free-draining compost formulated for germinating seed. It often contains a mix of fine materials including sterilised loam, coir, coarse sand or grit. It contains low levels of nutrients, as high levels could damage seedlings.

. Sow thinly and cover lightly with a thin layer of compost

Can refer to either home-made garden compost or seed/potting compost:

• Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

. Cover with glass, polythene or a propagator

A propagator is a portable, lightweight structure usually plastic, with a vented or unvented lid to provide a humid, slightly warmer atmosphere. It is useful to help seeds germinate and root cuttings. It may have adjustable, thermostatic temperature control.

lid and keep at approximately 20°C (68°F) until seedlings

A seedling is a young plant grown from seed.

appear.

Seed: sowing indoors

Sow outdoors in late spring (May) in a prepared seedbed

An area of soil prepared for sowing seeds. This usually involves weeding and raking to remove stones and clods, aiming to create a fine, crumbly soil texture and a firm, level surface. A seedbed is traditionally prepared away from the main veg plot for starting off slow-growing crops that in the long term need wide spacing, such as leeks and cabbages, to make best use of space on the main plot during prime sowing season.

.

Seed: sowing outdoors

Rudbeckias are robust, easy to grow plants but they can suffer from powdery mildew and aphids.

If rudbeckias grown as annuals

Annuals are plants that complete their life cycle in one growing season. They are generally easy to grow from seed or can be bought as young plants from garden centres. Annuals are ideal for growing in summer containers and filling gaps in borders. Some examples of annuals include sunflowers, cosmos, sweet peas and zinnia.

show scrawny poor growth, this usually indicates a lack of moisture. Water well in the summer to encourage good plant growth.