Plant spotlight – Selenicereus grandiflorus, ‘Queen of the night’ Copy

The first cultivated species of Selenicereus grandiflorus is mentioned by Carl von Linne (Linnaeus) in 1753, where he described it as the largest flowered species of cacti known at the time. However, it was introduced to Europe well before this, with historical records at Hampton Court Gardens mentioning it growing there prior to 1700.

Native to the Caribbean Islands and South America, it is an epiphyte, scrambling up trees and rocks, reaching for light. It has aerial roots and so does not look like the typical cactus as seen in Westerns.

The specific epithet grandiflorus means ‘large flowered’ in Latin and is an apt description for its elusive blooms.

Creamy white, vanilla scented flowers attract nocturnal pollinators in the form of bats and moths. Here at Winterbourne the Selenicereus grandiflorus has flowered consistently in May, with the flowers tending to open up at around 8-9pm. In the Botanist’s Repository of 1807, English botanist Henry C. Andrews quoted that “…few of Flora’s lovely train, warmed by the mid-day sun’s refulgent beams,…can compare with this nocturnal beauty”.

Sadly for Winterbourne visitors, the flowers close by the Garden’s 10.30am opening time.

It is this nocturnal flowering that gives the plant one of its most common nicknames; queen of the night the other being ‘vanilla scented cereus’, beautifully illustrated once again by Andrews in the same article, where he describes it as “perfuming the still cool air of midnight with its aromatic fragrance”.

Selenicereus grandiflorus can be grown as a houseplant with the key requirements being a minimum temperature of 5^oC and a lot of space! A frame will be needed to support it and it needs to be positioned somewhere with good light, such as a large window, heated conservatory or heated glasshouse. In the wild these plants are subject to some shade as they grow under the canopy of their supporting tree until they grow out of the top into the sun. Lack of shade can make the young plants vulnerable to scorch.

If the plant is getting too big for your chosen location it can be pruned and some growers actually recommend pruning to promote flowering.

It will need to go into a pot with good drainage, in a free draining mix with organic matter. One part sand to one part compost is a good basic mix. Grit or perlite can be mixed into the sand component and leaf mould can be mixed into the compost component.

From April to September the Selenicereus can be watered once a week. This is however dependant on temperature and light levels and if it is a long, cold, grey winter it might be worth waiting until May to start watering. From May to August it will benefit from a half strength feed once a week. At Winterbourne we use Chempak No. 8 (low nitrogen).

Cacti tend to be relatively problem free, but the main causes of problems are over or under watering, mealy bug or red spider mite.