The tropical genus Philodendron encompasses hundreds of species, and their mature size indoors is highly dependent on the specific variety and the conditions provided. These plants are native to the rainforests of Central and South America, where they can reach immense sizes, but their growth is naturally constrained within a home environment. Understanding the two main growth habits is the first step in predicting how large a particular specimen will become.
Two Distinct Growth Habits and Their Size Potential
Philodendrons are broadly categorized into two distinct growth types, which determines their size potential. The vining, or climbing, varieties are hemiepiphytes, meaning they root in the ground but use aerial roots to attach themselves to trees and climb toward the light in their native habitat. Species like the Heartleaf Philodendron (P. hederaceum) can reach lengths of 10 to 13 feet indoors if given a vertical support like a moss pole. Allowed to trail from a hanging basket, their vines will lengthen, though the leaves will often remain smaller than if the plant were actively climbing.
The second group includes the self-heading, or upright, Philodendrons, which typically grow as a dense, non-climbing rosette of leaves. These varieties, such as Thaumatophyllum bipinnatifidum (formerly P. selloum) or ‘Prince of Orange’, are generally more compact, forming a bushy shape. A mature self-heading plant can reach a height of 3 to 6 feet and a similar spread within a home. Massive plants like T. bipinnatifidum can exceed 6 feet with large, mature leaves up to 18 inches long.
Environmental Factors Limiting Indoor Growth
Philodendrons rarely achieve their maximum genetic potential inside due to the constraints of the average home environment. The single largest factor limiting growth is light intensity, as the lower light levels indoors significantly slow the rate of photosynthesis. Insufficient light results in smaller leaves, stretched out stems known as “legginess,” and a substantial reduction in the plant’s overall biomass production.
The size of the container is another physical constraint that directly restricts the plant’s growth. When roots become densely packed and “pot-bound,” a hormone signal is sent to the foliage, which slows new growth and limits the ultimate size of the plant. Furthermore, the tropical origin of these plants means they thrive in warm temperatures, ideally between 65°F and 85°F, and low indoor temperatures or cold drafts will slow metabolic processes.
Humidity also plays a substantial role, especially for vining varieties that rely on aerial roots to climb and absorb moisture. While a Philodendron can tolerate household humidity levels around 40%, a drop below this threshold can stunt leaf development and cause brown, crispy tips. In their natural environment, humidity levels often exceed 80%, which allows them to produce large, mature leaves.
Techniques for Managing Plant Size
Direct intervention allows a plant owner to actively control the size and shape of a Philodendron. The simplest method is pruning, which involves cutting the stems or vines back to a leaf node, the small bump where new growth will emerge. Trimming back up to one-third of the foliage during the growing season encourages bushier growth and keeps vining plants from becoming overly long and sparse.
For self-heading varieties that grow too large for their space, root pruning is an effective technique to maintain the plant in a smaller pot. This process involves carefully removing the plant from its container and using a sterile tool to trim away up to one-third of the root mass, usually from the bottom and sides of the root ball. The plant is then repotted into the same container with fresh soil, which resets its growth cycle and prevents it from expanding.
Using moss poles or trellises for vining types allows the plant to climb vertically, promoting larger leaf size, but the height is naturally capped by the length of the support structure. When a vining plant exceeds the desired size, the excess length can be cut and propagated by placing the stem cuttings in water or soil. This technique allows the owner to reset the plant’s size or create new, smaller plants.