'Black Knight' Βutterfly Βush - Buddleja davidii

'Black Knight' Βutterfly Βush - The Deep Purple Color of 'Black Knight' Βutterfly Βush Flowers
The Deep Purple Color of 'Black Knight' Βutterfly Βush Flowers

Among the varieties of Buddleja davidii, the ‘Black Knight’ Βutterfly Βush stands out.

It has an excellent shape, interesting foliage, as well as rich, long-term flowering with fragrant deep purple flowers, which attract in addition to the eyes and olfactory centers and a multitude of butterflies.

It is also a flowering shrub of extremely easy cultivation, if planted in the appropriate soil-climatic enviroment, and with minimal maintenance and care, will remain for many years in the garden or in the landscape, contributing aesthetically to the whole.

And of course this is another historical and classic variety of plant species – a thesis that is fully supported by the editorial team of "Kalliergeia" except of the well-known one and permanently disagreeing member, who is still in its ranks as an alibi of pluralism.

Let it be …

During the flowering period, the variety of Buddleja ‘Black Knight’ creates an attractive scenic "atmosphere".

Buddleja davidii 'Black Knight' in Blooming
Buddleja davidii 'Black Knight' in Blooming
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'Black Knight' Βutterfly Βush - General Elements

The basic characteristics of ‘Black Knight’ Βutterfly Βush, together with some concise identifications, are given immediately below.

Facts in Short

Family: Scrophulariaceae

Genus: Buddleja

Scientific Name: Buddleja davidii ‘Black Knight’

Common Names: Βutterfly Βush ‘Black Knight’, ‘Black Knight’ Βutterfly Βush, ‘Black Knight’ Buddleia

Plant Breeding Origin: Moerheim Nursery, Dedemsvaart – Holland (1959)

Awards: Award of Garden Merit of the Royal Horticultural Society, 1993


The ‘Black Knight’ Βutterfly Βush is not only one of the most historic varieties of the species but also represents one of the most serious attempts to create extremely dark colors in ornamental plants.

But especially for the Buddlejas – and in order to understand the size and importance of the project – it must be said that until now, no other variety of the species has approached the ‘dark’ shade of its flowers.

Additionally, one could supplement that tangible achievement is not just the really dark shade of its flowers but the fact that they emit vibrancy and intensity.

This vibrancy and intensity of Black Knight ‘s Βutterfly Βush deep purple color is called the plant lover, the gardener and the landscape architect to exploit, combine and eventually to showcase.

Buddleja davidii ‘Black Knight’

This variety of Buddleja is suitable for:

  • Specimen
  • Mass plantings
  • Informal hedges
  • Urban plantings
  • Pots & containers
  • Cut flowers

'Black Knight' Βutterfly Βush - Morphological Elements

‘Black Knight’ Βutterfly Βush is a perennial, woody, deciduous shrub with exceptionally fast growth. Under ideal conditions, it can exhibit an annual growth range of up to 1.5 m (5 ft), while its mature height being between 3.5 and 4 m (11-13 ft) and its diameter between 2.5 and 3 m(8-10 ft) .

The shape of the plant is ovoid-spherical, with a symmetrical crown, while it has a medium texture and an arching habit.

Buddleja davidii ‘Black Knight’

'Black Knight' Βutterfly Βush - Botanical Description


The branches, which are also due to their arching habit, grow from the base and after they first rise, then – especially after the formation of the flowers – they curve characteristically.

The bark in the twigs is grayish-green, while in the mature gray-brown and relatively smooth texture.


The leaves are velvety textured, have a lanceolate shape, silver-green color, which in summer becomes almost silver and in autumn turns to brownish-yellow and/or grayish-yellow. Their length is between 20 and 25 cm (8-10 in) while their width is 2.5 to 4.5 cm (1-1.8 in).


Flowers are developed at the top of the annual shoots on a racemes inflorescence of 18 to 21 cm (7-8.2 in) in length and 4 to 5 cm (1.5-2 in) in width. They are abundant, fragrant, their color is deep purple in the upper part and a little lighter purple to the bottom while their center is orange-purple.

Flowering is continuous and the flowering period is long, with a duration of 90 to 150 days, starting from the beginning of June and ending in late autumn.

Referring to Buddleja‘s flowers and flowering, it would certainly be a great omission not to say that the production of abundant nectar of them attracts insects among these bees and – what else? – all butterflies, even the rarest of each area.

Thus, Buddleja davidii ‘Black Knight’ fully justifies the English common name of the plant, which is Butterfly Bush and of course not Elephant – or something similar – Bush.

Buddleja davidii ‘Black Knight’

Butterfly on Flowers of the 'Buddleja davidii 'Black Knight'
Butterfly on Flowers of the 'Buddleja davidii 'Black Knight'

'Black Knight' Βutterfly Βush - Environment of Establishment


The ‘Black Knight’ Βutterfly Βush is more tolerant to cold than the typical species since its low temperature tolerance varies from -23 to -26 °C (-9.4 to -14.8 °F).

But without fear, can also being planted in areas where the lowest temperature reaches about -32 °C (-25.6 °F), but in this case its dimensions will be smaller, as well as the flowering period.

Generally, it can be said that while ‘Black Knight’ Βutterfly Βush is planted close to its low temperature limits, in the winter it may die back, but the base and roots area does not affects and therefore, in the spring the plant regenerate more strong and vigorous.

Soil and pH

In terms of soil, it has excellent adaptability as it can be cultivated up to calcareous gravel, as long as they drains well.

However, it thrives in deep, fertile, medium textured and high organic matter soils, while in terms of soil pH it prefers slightly alkaline.


In relation to the exposure, it is recommended that ‘Black Knight’ Buddleja is planted only in sunny places. If it is planted in semi-shade or if it receives direct sunlight for less than 6 to 8 hours, the appearance of the plant and the flowering is impaired.

'Black Knight' Βutterfly Βush - Care

The Buddleja generally belong to ornamental shrubs that do not need special care, beyond the elemental – and ‘Black Knight’ is no exception.


With regard to fertilization, providing a balanced 10-10-10 type fertilizer after the first 10 days of March and every month until August – September is particularly beneficial for the plant.


For irrigation, young plants should be watered – as is true for most ornamental plants – when surface soil at depths of 1 to 2 cm (0.4-0.8 in) have dried out. But since they well established, watering may be minimal, since the plant’s tolerance to drought is high.


A heavy pruning at the end of winter, it works refreshingly while encouraging more flowering. Still, the removal of mature inflorescences also helps in the production of more flowers, but in additionally prevents the formation of seeds, which and the plant "depletes" and naturally reproduces it – making it invasive in some areas.

Plant Protection

From diseases, it generally does not face a major problem, with the exception of rare occasions, however, of the Mosaic Virus.

In this case there is no suitable treatment and the plant should be immediately eradicated and burned to prevent further transmission of the disease.

 As for the pests, aphids, mites and caterpillars are mentioned, but here, with the use of appropriate formulations, parasites are treated effectively.

Video - Summary Information

Brief Information on the Care of the Buddleja davidii 'Black Knight'
Woman in the orchard with lettuce
Editorial Team
'Black Knight' Βutterfly Βush - The Deep Purple Color of 'Black Knight' Βutterfly Βush Flowers
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Buddleja davidii ‘Black Knight’

'Black Knight' Βutterfly Βush - Use in Garden and Landscape

The Buddleja davidii ‘Black Knight’ is utilized in various ways planted:

  • In seaside and coastal gardens, thanks to its resistance to salt spray
  • In medium and large urban gardens
  • In xeriscape gardens and in general in areas where the water available for irrigation is scarce
  • To create Butterfly gardens
  • In combination with other shrubs and flowering plants, such as Coppertips (Crocosmia x Curtonus ‘Lucifer’), Red Hot Pokers (Kniphofia ‘Alcazar’), Whorled Tickseed (Coreopsis verticillata ‘Grandiflora’ – syn. Coreopsis verticillata ‘Golden Shower’) and Eastern Purple Coneflower (Echinacea purpurea)


The References to the article entitled ‘Black Knight’ Βutterfly Βush – Buddleja davidii ‘Black Knight’, which is characterized by polyphony, are presented alongside by the Deep Purple flower band with their classic song Black Night – and not Black Knight.

With Pomp and Circumstance

Deep Purple in their youth play live in Copenhagen their song Black Night (1972).

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