Anthuriums, with their vibrant, waxy blooms and deep green foliage, are highly popular tropical houseplants. The most common varieties sold indoors are cultivars of the glossy-leafed Anthurium andreanum and the smaller, coiled-spadix Anthurium scherzerianum. Determining the maximum size of an Anthurium is complex because growth potential depends heavily on both its specific genetic background and the environment in which it is grown.
Understanding Varied Growth Habits
The overall size of an Anthurium is primarily dictated by its genetics, which categorize the plants into three distinct size groups. Most standard flowering varieties, such as A. andreanum hybrids, mature into a compact size, typically reaching 12 to 18 inches in height and spread. The naturally smaller A. scherzerianum usually stays under 18 inches tall.
Miniature or dwarf cultivars, often of A. andraeanum, have been bred specifically for small spaces, reaching a maximum height of 6 to 15 inches. These are ideal for terrariums or small desk displays. Conversely, foliage-focused species, favored by collectors, possess a vastly greater genetic potential, often dwarfing their flowering counterparts.
Species like the Queen Anthurium (A. warocqueanum) or the Crystal Anthurium (A. crystallinum) are known for their massive leaves. In optimal greenhouse settings, the velvety leaves of A. warocqueanum can reach lengths exceeding three feet, and in the wild, they can grow up to six feet long. The entire plant of A. crystallinum can spread up to 35 inches wide, with individual leaves growing over 18 inches in length.
Environmental Conditions That Influence Size
Even a genetically large Anthurium will remain stunted if its environment does not provide the necessary resources to fuel growth. Light intensity is a major factor, as Anthuriums require bright, indirect light to maximize photosynthesis and biomass accumulation. Low light levels significantly reduce the net photosynthetic rate, resulting in smaller leaves and an overall smaller plant structure. Providing an optimal range of light, often around 225 µmol, encourages the plant to reach its full growth potential.
The size of the container acts as a physical boundary that restricts the growth potential of the entire plant. Anthuriums are epiphytes, meaning their roots require excellent air circulation. Placing an Anthurium in an oversized pot can hinder growth because the excess soil holds too much moisture, suffocating the roots and inviting rot. This stress can severely stunt the plant, causing yellowing foliage and a reduction in new growth.
Consistent moisture and appropriate feeding are necessary for the plant to achieve maximum size. An Anthurium needs a well-aerated, coarse substrate that drains quickly, mimicking its native habitat. Regular feeding with a balanced fertilizer during the growing season supports the plant’s structural development, driving the production of larger leaves and stronger stems. Without adequate nutrient delivery, the plant will remain perpetually small.
Active Maintenance for Size Management
Growers can actively influence their plant’s size and shape through targeted maintenance techniques once genetic and environmental needs are met. Pruning is a primary method for managing plant appearance and redirecting energy toward new growth. Older, yellowing, or damaged leaves should be removed with sterilized shears, cutting the stem near the base. Removing faded flowers prevents the plant from expending energy on seed production, allowing that energy to be used for new leaves and flowers.
Aerial roots, which Anthuriums produce to absorb moisture and anchor themselves, can be tucked back into the potting mix to encourage vertical stability and new root growth. For plants that have become “leggy” with a bare main stem, repotting the plant deeper promotes the development of adventitious roots, which helps to stabilize and revitalize the plant. Maintaining at least four healthy leaves ensures the plant can continue to photosynthesize effectively.
Repotting frequency is a deliberate tool for size control. A grower wishing to keep a plant contained can delay repotting until the plant is visibly root-bound. For those desiring maximum size, repotting should occur every one to two years, moving the plant into a container that is only one to two inches wider than the current root ball.
Dividing Anthuriums
Dividing large, clumping Anthuriums is an effective way to reduce the overall bulk and create multiple smaller specimens. The process involves separating the plant into sections, ensuring each new division has its own healthy root system and top growth.