The genus Stanhopea, previously also known as Ceratochilus, Stanhopeastrum, Gerlachia, or Tadeastrum, belongs to the Orchidaceae family and was described by William Jackson Hooker in 1829, who named the genus in honor of the fourth Earl of Stanhope (Philip Henry Stanhope), president of the Medical-Botanical Society of London. The natural range of the Stanhopea genus includes Mexico, northwest Argentina, Central and South America, where it inhabits humid forests at altitudes from sea level up to over 5000 m.
Most Stanhopea species bloom in summer and only some during autumn. The strongly fragrant flowers have a short lifespan, lasting only 3 – 4 days, and generally emerge from the lower part of the planting baskets, giving the impression that the plants are overturned. The scent suggests spicy notes, and Stanhopea species are known for successive, repeated bloomings several times throughout the year
Stanhopea species grow epiphytically, occasionally terrestrially. They have ovate pseudobulbs with a single long, elliptical leaf inserted apically. In their natural environment, the aerial roots of these species often grow upwards, forming a nest-like structure where dead leaves and dust accumulate, providing nutrients to the plants.
Light intensity requirements for Stanhopea species fall within the range of strong, diffused light, approximately 25,000 – 30,000 lux, similar to species of the genus Cattleya, but avoiding direct sunlight, which can cause severe sunburn on the leaves. It is advisable to provide additional shading during the summer when daytime temperatures exceed 34 degrees Celsius.
The growth temperature, reflecting the origin of Stanhopea species from tropical and subtropical regions, but also from mountainous, high-altitude areas, generally falls within the range of low temperatures. Some tropical species, such as Stanhopea annulata, avicula, candida, cirrhata, ecornuta, and grandiflora, require nighttime temperatures above 18 °C to ensure successful flowering. As a general rule, most tropical species require minimum nighttime temperatures of 12 °C. Higher temperatures can reach the limit of 30–35 °C without causing significant problems in cultivating these species.
The Stanhopea orchid generally requires a high level of atmospheric humidity throughout the year, which is why frequent misting is recommended during the summer. Due to the high humidity level required by these species, ensuring very good ventilation is advised to prevent the development of fungal and bacterial diseases.
The ideal growing method for the Stanhopea orchid involves placing the plants in a wire basket with large holes, at least 1 cm in diameter, allowing the pendant flowers to penetrate the base of the growing container. Wooden baskets and standard pots can prevent this, leading to flowering failures. As a substrate, coconut fiber, medium to small-grain pine bark, ideally mixed with sphagnum moss, perlite, or Osmunda fern fibers can be used to provide a loose, airy, light growing medium with very low compaction and strong drainage. The most impressive blooms come from large, vigorous specimens, which is why excessive division of Stanhopea species is not recommended.
Repotting will be done infrequently, approximately every 3 years, and is generally avoided as it can delay flowering by up to 12 months. The ideal time for this intervention is summer, immediately after flowering has finished.
Watering can be done 2 – 3 times a week in the warm season (monitoring the temperature-humidity ratio), accompanied by daily misting during very hot periods to ensure constant humidity. In the cold season, avoid watering the leaves, as this can lead to bacterial leaf spots. For species originating from Central America, the substrate must never be allowed to dry out completely during winter, as the plants are very sensitive to salt accumulation in the substrate. Some species, such as Stanhopea hernandezii, insignis, jenischiana, leitzei, maculosa, and martiana, come from regions with dry winters, so it is recommended to reduce watering and provide a high light level during winter. For these species, normal watering resumes once new growth starts in spring.
Fertilization is done at regular intervals, with a 25% dilution of the recommended dosage on the package, every 2 weeks. For plants grown in bark, a 30 – 10 – 10 formula, rich in nitrogen, will be used alternately with a balanced 20 – 20 – 20 formula. For the flowering season, a 10 – 30 – 20 formula will be used to stimulate flowering.
The Stanhopea orchid does not require a rest period to stimulate flowering, nor a rest during the cold season. Failed blooms are most often due to insufficient watering during the summer, low temperature differences between day and night in spring, or too low humidity.
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