• AGM plants

    AGM plants have been through a rigorous trial and assessment programme. They are:

    • Excellent for ordinary use in appropriate conditions
    • Available to buy
    • Of good constitution
    • Essentially stable in form & colour
    • Reasonably resistant to pests & diseases

Kniphofia rooperiQuick facts

Common name Red-hot poker
Latin name Kniphofia
Group Perennial
Flowering time March to November
Planting time March and April
Height and spread 20-210cm (8in to 6½ft) and 20-100cm (8in to 3ft)
Aspect Sun
Hardiness Hardy to half-hardy
Difficulty Easy

Cultivation notes

Red-hot pokers make rewarding and often long-lived garden plants. Their distinctively-shaped blooms are among the most spectacular of hardy flowers, and their long season means that by careful plant choice gardeners can enjoy them between spring and late autumn.

Recent breeding work means there is a larger range and improved colours available to gardeners, with smaller habits and neater foliage. Colours range from red and orange through yellow to green and even brown and pink.

Planting in borders and containers
Kniphofias are generally easy to grow given the right conditions. For optimum performance choose a spot in full sun with fertile, well-drained soil that isn’t too wet over winter. Smaller, narrow-leaved cultivars such as ‘Bees' Sunset’ are easier to combine with other plants than the larger sorts, and grow well in pots and containers.

Aftercare

To help keep your red-hot pokers healthy;

  • Tidy plants in mid spring
  • Water container-grown plants regularly over the summer
  • Deadhead after flowering
 

Overwintering

Leave the plants alone until mid-spring as the old growth will protect the crown of the plant. Once the weather has begun to warm up, any dead or untidy-looking foliage can be pulled away – this will provide the opportunity to check for slugs and snails which can damage developing flowerheads and young growth. Rosettes of more tender species can be protected with fleece duing cold periods in winter.

Propagation

Although some modern seed mixes have been developed that will flower from seed in their first year, for the sake of speed pokers are generally purchased as pot-grown plants. They can easily be propagated by division in spring – this is the only way to increase named cultivars as they do not come true from seed.

Cultivar selection

Heights given are the flowering spikes, which are always taller than the foliage.

‘Bees' Sunset’ AGM (syn. ‘Shining Sceptre’) - incredibly colourful poker with orange flowerheads that fade to yellow as they age, borne on handsome bronze stems. Height 70-130cm

Kniphofia caulescens – one of the most striking species with beautiful, glaucous grey leaves and coral pink to orange red buds that open to creamy-yellow flowers. Used to great effect in the Dry Garden at Hyde Hall. Height to 90cm (3ft)

‘Elvira’ – this cultivar has the useful attribute of producing sterile flowers, so they don’t turn brown before they fall off, giving it a much ‘cleaner’ look than some of the others. Flowers are pure orange and continue from July until the first frosts. Height 60-100cm (2-3ft)

K. northiae AGM – the best poker for foliage – its agave-like rosettes lend an exotic touch. Much hardier than it looks. Height up to 170cm (70in)

K. rooperi AGM – unmistakable round flowerheads of orange, red and yellow. Although it blooms in winter in its native habitat, forms in cultivation including ‘Maxima Globosa’ flower in September and October in the northern hemisphere – making them valuable in the autumn garden. Height 60-155cm (2-5ft).

‘Tawny King’ – chosen by Christopher Whitehouse, author of Kniphofia - the complete guide, as his favourite cultivated poker. Tall and dramatic with bronze stems and flowers that change from dark, smouldering orange though apricot to creamy white. Unusual and remarkable. Height 90-130cm (3-4ft)

K. thomsonii var. thomsonii 'Stern's Trip' AGM – an unusual poker with delicate, widely-spaced flowers. These start dark red-orange and become brighter in colour as they open. Not reliably hardy outdoors in the UK, except in mild areas. Height 90-140cm. (3-4½ft)


Kniphofia - the complete guide

For unparalleled information on red-hot pokers, their species, cultivars and cultivation, see the first in our series of horticultural monographs, Kniphofia - the complete guide - see a preview below:
 



Links

RHS Plant Finder
RHS Plant Selector
AGM Plants
Kniphofia - the complete guide (RHS monograph)

Problems

Kniphofias generally suffer from few pests and diseases – slugs and snails being the most frequent. It’s worth being vigilant as the flower spikes emerge as these are the most vulnerable parts of the plant.

Root rots (including Fusarium and Phytophthera) can occasionally affect pokers. Symptoms initially resemble those of drought stress, including wilting and dull-coloured leaves. Once rot has spread to the crown of the plant, its leaves will pull away easily. Dig up and destroy affected plants, and do not replant in the same spot. To avoid root rots, always plant kniphofias in well-drained soil.

Aphids can sometimes attack flowerheads – try to avoid using any form of insecticide as there is a risk of harming beneficial wildlife too. A gentle squirt with a hose should be enough to dislodge the pests.

See also...

Bananas
Bulbs
Dahlia
Palms: hardy
Strelitzia


Pick of the pokers

Read an article from The Plantsman detailing the species and best cultivars from the most recent RHS Kniphofia trial.



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