Dahlia King Arthur

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Bulb size I

4,90 €

Price per item 4,90 €
Price for 3: 12,90 € i.e 4,30 € each

Sku: 211581

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More information

The flowers of this Decorative Dahlia measure approximately 10cm (4in) in diameter and their colour changes depending on their stage of blooming. They are initially purple and eventually turn into a vibrant red, with a velvety appearance. This beautiful bush blooms from July until the first frost and can reach a height of 1m (3ft). Its flowers are stunning in a bouquet.

Flower size

10 cm

Height at maturity

1 m

Spread at maturity

60 cm

Exposure

Sun

Hardiness

Hardy down to -4°C

Soil moisture

Moist soil

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Best planting time March to April

Recommended planting time March to May

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Flowering time July to November

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Description

Dahlia 'King Arthur' is characterised by small-sized flowers (about 10cm (4in) in diameter) whose colour evolves as the flower opens. Initially dark red with a velvety appearance, they gradually turn bright red. This lovely bush blooms abundantly from July until the first frosts and can reach 1m (3ft) in height. Its flowers are beautiful in bouquets.

From the Asteraceae family, dahlias are tuberous plants native to the high plateaus of Mexico. Currently, there are thousands of horticultural varieties that have conquered gardens worldwide. Dahlias are classified according to the shape of their flowers. The variety 'King Arthur' is part of the Decorative Dahlias with small flowers. They are characterised by ligules (like petals) arranged regularly in a spiral, which can be bent towards the stem or curly. This variety won the press prize at the international dahlia competition in 2023.

The heads of the 'King Arthur' variety measure about 10cm (4in) in diameter. The flowering occurs from July until the first frost. The bushy and erect plant will reach about 1m (3ft) in height, and 50 to 60cm (20 to 24in) in width. The stems are hollow and therefore fragile in windy conditions. The green leaves are opposite, divided into 3 or 5 leaflets.

To promote flowering and extend it at the same time, make sure to remove the faded flowers as they appear. Use the flowers to create lovely countryside bouquets, by combining complementary colours and sizes and shapes of blooms. Plant several dahlias in a flower bed or plant several varieties in the vegetable garden for a varied display. The flowers of Dahlia 'King Arthur' will perfectly complement those of Dahlia 'Aramis' with large purple flowers, or the pure white blooms of Dahlia anemone 'Zahra'.

Undisputed stars of cottage gardens, Decorative Dahlias pair well with gauras and cleomes, which lighten their generous silhouette. Also consider echinaceas and salvias such as Salvia microphylla 'Caramba' with red flowers and variegated foliage.

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Family sheet

Modified the 24 August 2025 by Virginie T. 19 min.

Dahlia: planting, care and growing tips

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Plant habit

Height at maturity 1 m

Spread at maturity 60 cm

Growth rate fast

Flowering

Flower colour red

Flowering time July to November

Inflorescence Flower head

Flower size 10 cm

Good for cut flowers Cut flower blooms

Foliage

Foliage persistence Deciduous

Foliage colour medium green

Botanical data

Genus

Dahlia

Cultivar

King Arthur

Family

Asteraceae

Origin

Cultivar or hybrid

Product reference • 21158

Planting and care

It is easy to grow in all regions. Plant the tubers in the sun after the last frost. Rich, moist, and well-drained soil will be greatly appreciated. Avoid any stagnant moisture that promotes tuber rot. Amend your soil with compost (if the soil is poor) and with sand (for drainage), if necessary. Work your soil deeply and enrich it with crushed horn or dehydrated blood, whichever you prefer. Place your tuber and crumble the soil around it to fill any air pockets. The dahlia should be covered with about 6cm (2in) of soil. Water abundantly at planting and regularly during the first six weeks to assist with rooting.

Dahlias are sensitive to cold, so they need to be overwintered. In November, the first frosts blacken the foliage, which is the time to dig them up. Carefully remove the tubers. Remove as much soil as possible. Let the foliage dry so that the tubers can replenish their reserves. Then cut the stems to 10cm (4in). Spread your tubers in a box on newspaper. Store them in a frost-free, dry, cool, and dark place, such as a garage or attic. It is possible to leave them in the ground in warm regions, close to the coast, where there are few frosty days per year. In this case, simply cover the ground with a thick mulch (leaves, straw, etc.).

Pinch the shoots early (from the 3rd or 4th week after planting) to make your dahlia more compact and branched, and therefore more resistant to bad weather (wind, rain). To do this, cut the terminal shoots just above the previous leaves with your nails. Otherwise, you always have the option of staking, but the aesthetic result may not be the best.

Slugs and snails are very fond of these young shoots. Protect them!

Planting period

Best planting time March to April

Recommended planting time March to May

Planting depth 10 cm

Intended location

Suitable for Meadow

Type of use Border, Back of border

Hardiness Hardy down to -4°C (USDA zone 9b) Show map

Ease of cultivation Amateur

Planting density 4 per m2

Exposure Sun