Anthuriums are popular houseplants, often admired for what appears to be a vibrant, waxy flower. This colorful structure is not a true flower, but an inflorescence—a specialized reproductive part of the plant. Understanding this distinction is key to appreciating their unique biology and providing optimal care.
Understanding the Anthurium Inflorescence
The anthurium inflorescence comprises two primary components: the spathe and the spadix. The spathe is the prominent, often colorful, heart-shaped or lance-shaped structure. It is a modified leaf, or bract, that encloses and protects the spadix.
The spadix is the central, fleshy, finger-like spike emerging from the spathe. Along this spadix are the true, tiny anthurium flowers, arranged in close spirals. These individual flowers are bisexual, containing both male and female reproductive parts. The spathe’s purpose is to attract pollinators to these flowers.
The Role and Diversity of the Inflorescence
The primary function of the anthurium inflorescence is reproduction, achieved by attracting pollinators. The spadix undergoes a maturation process with distinct female and male phases to prevent self-pollination. During the female phase, the spadix produces stigmatic fluid, indicating receptiveness to pollen. The male phase then begins, releasing pollen and often changing color or texture.
Anthurium inflorescences show great diversity across the genus, which includes over 1,000 species. Spathes, commonly red or pink in cultivated varieties, can be white, green, black, orange, purple, or multi-colored. They also vary in shape, from heart-shaped to tulip-shaped, ribbon-shaped, or cup-shaped, and can be flat or puckered. The spadix also varies, from elongated spikes to globe-shaped or corkscrew forms.
Optimizing Conditions for Blooming
Bright, indirect light is important for promoting bloom production and maintaining color vibrancy. Place the plant where it receives filtered sunlight for at least six hours daily, such as near a north or east-facing window. Direct harsh sun can scorch spathes and leaves; 1500-2000 footcandles is recommended for optimal flowering.
High humidity is important for the spathe’s development and health. Anthuriums are tropical plants that thrive in humid environments; low humidity can cause browning or crisping of spathe tips. Use a humidifier, mist regularly, or place the plant on a pebble tray to maintain moisture levels around the foliage and inflorescence.
Fertilization practices also support blooming. Anthuriums benefit from a fertilizer with higher phosphorus (middle number in NPK ratio, e.g., 10:30:20 or 1:2:1) to promote flowering over vegetative growth. Fertilize every few weeks during the growing season with a diluted solution, typically at quarter strength, for consistent flower production.
Common Inflorescence Issues
Several issues can affect anthurium inflorescences. A lack of blooms often stems from insufficient light, improper watering, or inadequate nutrition. Over or under-fertilization can also hinder blooming, as can crowded roots from infrequent repotting.
Browning or crisping of the spathe indicates low humidity or direct sunlight exposure. These tropical plants need consistently moist air; dry conditions cause spathe edges to dry and brown. Greening of the spathe, where the colorful bract loses its vibrant hue, can occur due to age, insufficient light, or greenhouse practices that force early blooming.
A brown or soft spadix may indicate overwatering, cold damage, or natural aging. Removing spent or damaged inflorescences helps the plant redirect energy toward producing new, healthy blooms.