The term “Queen Plant” is an informal designation for various species, often due to their striking appearance or unique blooming habits. This article focuses on the “Queen of the Night” cactus, a name primarily associated with Epiphyllum oxypetalum and Selenicereus grandiflorus. These cacti are celebrated for their remarkable nocturnal flowers, making them a popular choice for enthusiasts.
What is a “Queen Plant”?
The designation “Queen Plant” is an informal descriptor for plants exhibiting regal qualities like majestic size, showy flowers, or elegant growth. Examples include Queen’s Tears (Billbergia nutans), a bromeliad with pendant, nectar-releasing flowers; the ornamental Queen Palm (Syagrus romanzoffiana); and Queen’s Wreath (Petrea volubilis), a tropical vine with purple flower clusters.
However, the most renowned “Queen Plant” for many gardeners is the “Queen of the Night.” This name typically refers to two specific night-blooming cacti: Epiphyllum oxypetalum and Selenicereus grandiflorus. These epiphytic cacti, native to tropical and subtropical Central and South America, are popular for their unique flowering spectacle: large, fragrant blooms that unfurl only after dusk.
Cultivating the Queen of the Night Cactus
Cultivating the Queen of the Night cactus, whether Epiphyllum oxypetalum or Selenicereus grandiflorus, involves replicating their native tropical environments. As epiphytic plants, they naturally grow on other plants or rocks, absorbing moisture and nutrients from the air and debris rather than soil.
Light Requirements
Queen of the Night cacti thrive in bright, indirect light, mimicking the dappled sunlight under a tree canopy. An east or north-facing window indoors is ideal, as direct afternoon sun can scorch their stems. While Selenicereus grandiflorus tolerates some morning sun, intense exposure is detrimental. Insufficient light leads to leggy growth and may prevent blooming.
Watering Needs
These cacti require consistent moisture during their active growing season (spring and summer), but they are not tolerant of soggy conditions. Water thoroughly until drainage occurs, then allow the top inch or two of soil to dry before rewatering. Overwatering causes root rot, while underwatering leads to stunted growth. During cooler, dormant months, reduce watering significantly.
Soil and Potting
A well-draining, airy potting mix is crucial for Queen of the Night cacti, given their epiphytic nature. A suitable mix resembles an orchid medium, incorporating components like perlite, orchid bark, and peat or coco coir. This ensures proper aeration and prevents waterlogging. Pots must have drainage holes to prevent root rot.
Temperature and Humidity
Queen of the Night cacti prefer moderate temperatures, typically 50°F to 85°F (10°C to 29°C), and are not frost-tolerant. They can be moved outdoors in warmer months but must be brought inside below 50°F (10°C). These plants appreciate higher humidity levels. While they adapt to average household humidity, a humidity tray or humidifier can be beneficial.
Fertilization
During the active growing season (spring through summer), Queen of the Night cacti benefit from regular fertilization. Apply a balanced, water-soluble fertilizer, diluted to half strength, every two to four weeks. A low-nitrogen, phosphorus-rich fertilizer can encourage blooming, especially before and after flowering. Reduce or stop fertilization during the plant’s dormant winter period.
Repotting
Repotting is generally needed every two to three years or when the plant outgrows its container. The best time to repot is in spring, before the new growing season. Select a pot only slightly larger than the previous one, as these cacti bloom better when somewhat root-bound. Ensure the new pot has adequate drainage.
The Enigmatic Blooms of Queen of the Night
The primary allure of the Queen of the Night cactus is its spectacular, fleeting nocturnal bloom. Large, trumpet-shaped flowers, typically white or creamy white, unfurl after sunset, reaching full grandeur around midnight. These blossoms can measure up to 12 inches long and 8 inches across, emitting a strong, sweet, gardenia-like fragrance that attracts nocturnal pollinators like bats and moths.
Each flower lasts only a single night, wilting by dawn. The plant typically blooms once a year, usually in late spring or summer.
Encouraging blooms requires specific care: sufficient bright, indirect light, and plant maturity, as young plants may not flower for several years. A cool, dry winter rest period (around 50-55°F or 10-13°C) with reduced watering helps stimulate bud formation. Consistent, appropriate fertilization during the growing season also contributes to successful flowering.
Common Problems and Solutions
Yellowing leaves or stems often signal overwatering or poor drainage, leading to root rot. If stems are soft or mushy, unpot, inspect roots, remove rotted sections, and repot in fresh, well-draining soil. Brown, crispy edges indicate insufficient watering or excessive direct sunlight.
Lack of blooms can stem from insufficient light, plant immaturity, or nutrient imbalance (too much nitrogen promotes foliage over flowers). Adjusting light, ensuring maturity, and using a phosphorus-rich fertilizer can encourage flowering.
Pest infestations are generally infrequent, but mealybugs, spider mites, and scale insects can occasionally affect these cacti. Inspect the plant regularly and treat infestations with insecticidal soap or neem oil. Stunted growth or wilting leaves may also indicate pest issues, improper watering, or nutrient deficiencies.