Grown for years as a Notocactus, until all Notocacti suddenly found themselves to be Parodias, P haselbergii was also included in the genus Brasilicactus set up by Backeberg. It was discovered by, and named after, the remarkably little-known collector Dr F von Haselberg.
In habitat it grows in the Rio Grande do Sul, the most southerly state in Brazil, mainly in the forested mountains of the Aparados da Serra in the northern part of the state. In cultivation it will do well in a very well-drained slightly acid compost in a bright position, although it is best to avoid too much hot summer sun. It can be cold-sensitive in winter, so keep it well above freezing (8-10C) and make sure it is completely dry.
P haselbergii is generally one of the earliest plants to flower each year. The vibrant red/orange flowers are not as spectacular as those of some Parodias, but each flower can last for up to three weeks, making them probably the most long-lasting of all cactus flowers.
The plant formerly known as Notocactus graessneri is now recognised as a subspecies of P haselbergii. This has golden yellow spines and unusual yellowish-green flowers, although confusingly the variety v albisetus has whitish spines. Both plants often have a slanted apex, which helps to prevent the accumulation of water on the crown.
Both P haselbergii and ssp graessneri are often seen in garden centres but look carefully before you buy. They are very susceptible to red spider mite, and I have often seen plants for sale which are already disfigured by this pest.
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