The bishop’s cap owes its quirky name to its somewhat whimsical, almost spherical growth form. This thornless cactus comes from the Mexican desert and scores points as a small houseplant with its charm. But although the survival artist is very frugal, there are a few things to keep in mind when caring for it. We tell you what is important.
Origin of the Bishop’s Cap
The bishop’s cap (Astrophytum myriostigma) originates from the Chihuahua Desert in Mexico. The genus belongs to the cactus family (Cactaceae). In the arid regions of North America, the small plants are exposed to extreme weather and stony, inhospitable soils. In winter, they also endure extreme temperature fluctuations of up to 20 degrees Celsius between day and night.
Growth and appearance
Thanks to their stony home, bishop’s caps manage extremely well with little water. This makes them ideal for forgetful indoor gardeners and novices.
The bishop’s cap grows almost spherical at first, until it approaches its more cylindrical shape after a few years. Its interestingly shaped protuberances on the plant body are called “ribs”. Astrophytum myriostigma can have between three and eight ribs. The entire surface of the plant is studded with soft, woolly flakes. Seen from a distance, it therefore often does not look green, but has a silvery or greyish shimmer. Other subspecies of the genus, such as Astrophytum myriostigma nudum, are not blessed with such a felt-like coating. Bishop’s caps reach a height of up to 30 centimetres.
Flowers and fruits of the bishop’s cap
One or more yellow flowers adorn the bishop’s cap from March to October. They consist of many lanceolate petals. Towards evening, as dusk slowly begins to fall, the flowers close; only to reawaken at dawn and open again. Afterwards, light green, egg-shaped fruits emerge from the flowers, which burst open as soon as the seeds have ripened.
Bishop’s caps need sufficient light, which is why a place on a south-facing windowsill is ideal. In the summer months, you can also let the bishop’s cap enjoy a little fresh air – preferably in a covered place. In winter, the cacti take a rest period, so it can be cooler during this time. However, the bishop’s cap should be kept in a sufficiently bright place all year round.
Clay pots have a big advantage over plastic pots. The clay walls can protect against waterlogging by automatically absorbing excess water. This is just right for the bishop’s beanie. It can be very sensitive to moisture.
Planting and care
Plant the bishop’s cap in cactus or succulent soil. These substrates have a high rock content, good water permeability and tend to be low in nutrients. Avoid too heavy, nutrient-rich and humus-rich soil.
Caution: Never use organic fertiliser for the bishop’s cap. This cactus species is at home in stony areas and organic material such as compost does not agree with it.
As with almost all cacti and succulent plants, the following also applies: water moderately. Allow the surface of the soil to dry out well before adding more water.
Because the bishop’s cap grows quite slowly, it only needs repotting every few years. When the time comes, remember not to forget drainage in the form of lava rock or perlite. Over spring and summer you can support the cactus with a low-dose cactus fertiliser.
You can propagate the bishop’s cap via its seeds. For this you should keep the seeds until spring, as sufficient sunlight is needed for germination. The bishop’s cap is a light germinator, which is why you do not press the seeds down in the substrate, but simply place them on top. Use cactus soil for this and moisten it before spreading the seeds. For successful germination, temperatures should be between 20 and 25 degrees Celsius.
Diseases and pests
Bishop’s caps are without doubt one of the most robust cacti species. The greatest danger lies in prolonged waterlogging, which can initially promote root rot and, in the worst case, even lead to the death of the plant. Root rot can be recognised by soft, almost muddy plant parts.
Use of the Bishop’s Cap
With its rounded growth, the bishop’s cap is a nice-looking houseplant. But it is not only its shape that makes it a special cactus – the lack of spines is also rather a rarity. This makes it one of the few child- and pet-friendly cacti. If you keep it according to its habitat requirements, you will have a loyal companion.