Hoyas, or wax plants, are popular houseplants appreciated for their waxy foliage and fragrant, star-shaped flowers. Many species are naturally epiphytes, meaning they grow harmlessly on structures like tree trunks or rocks in their native tropical and subtropical habitats across Asia and Australia. Hoyas are vining plants that seek vertical support. Providing them with a structure to ascend mimics their natural environment, allowing them to thrive and display more mature growth characteristics.
The Biological Mechanism of Hoya Climbing
The ability of a Hoya to climb is rooted in two distinct biological mechanisms: specialized aerial roots and the behavior of new, searching vine growth. Climbing allows these plants to move upward toward brighter light filtering through the dense forest canopy, which is a strong evolutionary advantage. This behavior causes many species to produce long, seemingly leafless tendrils when seeking a place to attach.
The first mechanism involves adventitious roots, often called aerial roots, which grow from the nodes along the stem. These roots are primarily used for anchorage, gripping onto rough surfaces like bark or rock texture. While they can absorb some moisture and nutrients, their main function is to secure the plant to its support, allowing the vine to ascend safely. These roots are often white or light-colored and develop more readily in high humidity.
The second method involves the plant’s new growth tips, which engage in a searching behavior known as twining. As a new vine extends, it coils around any nearby support structure it encounters. This coiling action, combined with the gripping power of the aerial roots, firmly attaches the Hoya to its ascent path. If a vine grows downward or fails to find suitable support, the plant may abort the growth tip and attempt to send out a new vine elsewhere.
Vining vs. Trailing: Understanding Hoya Growth Habits
While Hoyas are biologically equipped to climb, they are frequently grown indoors in hanging baskets, which forces them into a trailing or cascading habit. This difference in display impacts the plant’s overall appearance and maturity, as the plant responds differently to vertical versus horizontal growth. The choice between vining and trailing is a matter of preference, but understanding the plant’s natural inclinations is important.
Allowing a Hoya to climb encourages a more mature growth pattern, often resulting in larger, more robust leaves. Vertical support signals the plant has reached a stable position, prompting it to invest energy into foliage development and flowering. Although it takes a few years for a Hoya to mature enough to bloom, providing vertical support can accelerate this process.
In contrast, letting a Hoya trail can sometimes lead to thinner, less robust vines with smaller or more sparse leaves, especially on strong climbers. This trailing habit does not prevent flowering, but it can slow the plant’s overall development toward maturity. Vigorous climbers like Hoya carnosa and Hoya pubicalyx will readily trail but often produce long, bare “runner” vines when seeking a place to climb.
Providing Support for Optimal Hoya Growth
To encourage the most vigorous and mature growth, houseplant owners should provide a suitable support structure. This support can come in several forms, including moss poles, trellises, and simple stakes, each offering a different aesthetic. The ideal material should allow the Hoya’s aerial roots to grip securely, which is why bamboo, wire, and coir moss poles are popular choices.
Wire hoops or U-shaped bamboo trellises are often favored for their simplicity and ability to fit within a small pot. Bamboo is a natural, cost-effective option, while metal wire is easy to clean and offers a non-porous surface that discourages pests. Moss poles, made from sphagnum moss or coir, provide the most beneficial surface because they mimic a tree trunk and retain moisture, encouraging aerial roots to attach readily.
Training the vines involves gently guiding the new growth to wrap around the support. The newest growth tips are delicate and flexible, making them easier to wind around the structure. Secure the vines temporarily using soft plant ties, Velcro, or small clips until the aerial roots have firmly attached. Avoid forcing stiff, older growth, as this can easily snap the stem.
If a Hoya is becoming too large, you can prune it back to a node, which will encourage the plant to branch out and become bushier. However, avoid cutting the small, woody structures called peduncles, which are the spurs from which the plant blooms. Since the Hoya produces flowers from these same points repeatedly, preserving them is essential for future flowering.