Thick-stemmed begonias are characterised by producing typically one (sometimes more) robust stem, displaying reluctance to bush out into a compact plant. Often requiring staking, these begonias demand considerable attention to cultivate an aesthetically balanced plant. Varieties such as Pearle de Lorraine, olbia, and fernando costae fall into this category, showcasing the diverse nature of thick-stemmed begonias.
Despite the variability in the thick-stemmed description, these begonias share the commonality of thick stems that tend not to branch extensively, instead initiating new growth from the base. The thick stems become exposed as they mature, especially as lower leaves drop off, leaving only newer leaves at the tips. This feature adds an element of uniqueness and attractiveness, making them a distinctive choice for growers seeking something different.
All Cane-Like and Shrub-Like begonias develop thick stems, but the thick-stemmed group stands out for maintaining thick stems from the base to the tip throughout their growth. While some varieties may reach considerable heights, most hover around one meter, making them particularly intriguing for collectors. These begonias require ample space, whether grown in gardens or pots. When potted, it’s crucial to provide a large, deep container for stability and optimal root development. As house plants or in courtyards, they thrive in well-lit positions with some morning sunshine, avoiding hot afternoon sun to prevent sparse flowering and lanky growth.
For optimal growth, young plants are best started in small pots and gradually moved to larger ones as they develop. Restricting pot size controls plant size effectively. Both garden soil and potting mix should be free-draining, and regular fertilization is essential for robust stem development.
These begonias tolerate a wide temperature range, with the ideal temperature range being 18º C to 22º C. In colder weather, growth may slow or cease, but the plants recover with warmer conditions. While branching is not typical for many thick-stemmed begonias, early-stage tip pruning encourages branching, resulting in a fuller and more appealing plant. It’s advisable to remove old stems completely, promoting new growth from the roots.
Watering follows the general guidelines for begonias, avoiding waterlogged conditions. Fertilization plays a crucial role in ensuring strong stem growth. Propagation can be achieved through seeds, stem cuttings, or leaves. Cuttings, once rooted, are transferred to small pots and fertilized with a water-soluble fertilizer, emphasizing the importance of good light without direct sunlight.
Begonia Society of Western Australia 