Habitat: United States and Mexico, Sonora Desert.
Cultivation: Portulacas don’t require any special care, so they are perfect to adorne your gardens or balconies!
Curiosity: Its name comes from the greek words “Penios”, meaning “thin”, and “cereus”, which is “candelabra”. It refers to its slender stem and the typical branching organization of many cacti, which gives the impression of a candelabra. Also, this genus is famous for its abundant, night-blooming blossoming and it is known as “Night-blooming cereus” and “Queen of the night cereus”.
Peniocereus is a genus of vine-like, night-blooming cacti, including 18 species native to south-western United States and Mexico.
Their habitat are desert scrublands in arid habitats, or either tropical, dry deciduous forests, where they are nearly invisible during most of the year, being hidden by the shrub on which they trail. If they are kept safe from the herbivores, their stems can grow up to 3 meters in height! Many species of Peniocereus are threatened due to habitat loss and pollution. The main problem is the reduction of the populations of hawk moths, the main pollinators of these cacti, caused mainly by pollution. A fashinating peculiarity of these hawk moths is that they can fly for many kilometers in search for Peniocereuses, which are their preferred source of nectar. Their flowers, in fact, aren’t self-fertile and the cross-pollination between different plants is required. Lacking the pollinators, flowers do not attach and fruits and seed can’t be formed, thus the plant can’t reproduce. This is a typica example of chemical habitat fragmentation: though the habitat look intact, pollution indirectly destroys it by damaging its insects, which indirectly damage the plants populations.
Seeds, instead, are spread from bird, which are attracted by the fleshy, red fruits: they eat the pulp and spread seeds through their droppings.
Peniocereus have not the typical upright habit of other Cactaceae: they are, usually, vines clinging on other succulent bushes, which provide shade and physical support, with their stems more narrow and less succulent than in most other Cactaceae.
Their slender stems are cylindrical and reach 2 centimeters of diameter. Usually, they are divided into 6-10, not so pronounced ribs, and are pale green, with a reddish-gryish tinge. The areoles, namely the buds of the family Cactaceae, from which spines sprout, are usually whitish and lined up along the ribs. Spines can be small and or absent, like in P. maculatus, or more pronounced, depending on the species. Young stems may be covered in a white fluff.
The plants grow from a large tuberous root, which can reach 20 kilos! Whenever a stem is eaten by a herbivore, it is suddenly replaced by a new one thanks to the tubers ability to produce abundant new stems. The tubers are also used as a stock of water and nutrients and allow the cacti to survive the harsh conditions of their natural, rather arid environment.
Peniocereus are famous for their spectacular blooming, which occurs at night. They usually have white or pinkish red, big flowers with numeros, lanceolate petals, arranged in two layers: the upper one facing upwards, and the lower one which is more wide and facing outwards, surrounding a central, abundant bunch of stamens (the stamens are the male reproductive organs of the flowers).
Another peculiarity of these cacti is that, in their natural habitat, the same populations bloom in synchrony.
VARIETY AND TYPES
Here below are the accepted species of Peniocereus:
- P. castellae
- P. castellanosii
- P. chiapensis
- P. cuixmalensis
- P. fosterianus
- P. greggii
- P. haackeanus
- P. hirschtianus
- P. johnstonii
- P. lazaro-cardenasii
- P. macdougallii
- P. maculatus
- P. marianus
- P. marnierianus
- P. oaxacensis
- P. occidentalis
- P. occidentalis
- P. papillosus
- P. rosei
- P. striatus
- P. tepalcatepecanus
- P. viperinus
- P. zopilotensis
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TIPS FOR GROWING
Here below are our cultivation tips for Peniocereus:
- It requires an exposure to partial shade, as, in its natural habitat, it’s used to climb on other plants. However, a partially exposed position will do well anyway.
- It is preferable to keep it at mild temperatures and never below 12-15 °C, for this reason it is recommended to shelter it during the winter period, although it can actually bear temperatures around 0ºC id if its substrate is maintained dry.
- Water moderately and only when the soil is completely dry. It is enough to water it once a week in spring and summer, reduce it to once every two months in autumn and to suspend it completely in winter.
- A well-draining substrate, rich in mineral nutrients, is an optimal solution. For example, a soil suitable for cacti mixed with pumice, can do well, better if the organic matter is maintained at a rate around 15-20%.
- It’s important to choose deep, cylindrical pots, to host its big, tuberous roots.
- Provide your Peniocereus with a structure to which it can cling, as it’s a vine cacti!
- They do not need frequent fertilizations, it is enough to dilute fertilizer with watering once a year.
Propagation is usually carried out through stem cuttings. Also in their natural habitat the branches, when accidentally detached from the main stem, tend to put roots as they touch the soil. Also, to plant parts detached from the tubers is possible.