05/17/2023
Tolumnia hamiltonii Sauleda 2019, a Jamaican twig epiphyte with large flowers relative to the plant. This species and Tolu. guttata, another pink species, produce a hybrid swarm, or syngameon, known as Tolu. x pulchella, that many may have known as a species for many years. Published in 2019, once the hybrid origin was understood, many fine, large-lipped, select pulchella over the years may have been nearly or entirely hamiltonii, in reality.
Uncommon in cultivation, Tolumnia once had a thriving US hybridization boom in the late 20th century, starting largely with the efforts of the great and prolific hybridizer, Goodale W.W. Moir. Starting in the 1950s, he popularized what were often called "Moir's weeds," as they were seen as insignificant roadside flowers among locals across the Caribbean. In the late 1990s, Richella Orchids and Robert and Susan Perreiras of Hawaii and Sundance Orchids of Galveston, TX took breeding of these charming plants to a zenith. These days, Tolumnia are rarer and rarer in collections and shows, which is truly a shame, as they have many good selling points. The plants are small (though some species have strongly scandent, stoloniferous growth), thrive in heat, humidity, and breeze, can be grown alongside Cattleyas or even Vandas, and they can achieve specimen size in a 3-4" pot full of fans of fleshy, succulent leaves. They come in a range of colours from white to yellow, pink, purple, and red, variously spotted, barred, flushed, and veined with colours and patterns that may develop, change, or fade as flowers open and expand. Finally, they have a primary flush of long-lasting blooms, most species starting in early spring, then the spikes branch and rebloom, quite frequently resulting in blooms well into summer, even fall for the later bloomers.
So why aren't they more popular? For starters, with the loss of commercial breeders working in the genus domestically, and paucity of imports from other countries, Tolumnia have really dropped off the sales tables in the US. Furthermore, Tolumnia have a reputation as "difficult" or "quick to die." The key to this issue is in the natural adaptations of Tolumnia. The triquetrous, succulent leaves of Tolumnia, as well as their scrambling, wiry roots are evolved for twig epiphytism. The species grow in scrubby trees, shrubs, even tropical cacti, and are evolved to inhabit thin branches well-exposed to sea breezes, humidity, frequent rains, and nightly mists as humidity in air off the water comes ashore and condenses as it rises up island elevation. This bright, airy, frequently moistened but fast to dry environment requires significant adaptation to explore a niche with few epiphytic competitors for light. Tolumnia breed and grow FAST, under two years seed to bloom, allowing them to colonize new growth and exploit disturbed habitats, often some of the first vegetation to reestablish after hurricanes. Their thickened leaves are evolved to hold water and reduce surface to volume ratio, preserving water like other succulent plants' leaves or stems. Their very fine, wiry roots are designed to tangle around bare twigs, fully exposed to breezes and evaporation. The elegance of their adaptation to what amounts to clinging to twigs in prime hurricane territory means one important thing: Tolumnia cannot live with wet feet. They absolutely must be bone dry within 24-48 hours after watering. Wet feet means rot, which moves very quickly through fine roots and the very tiny pseudobulbs in leaf fans. Large plants can often rot out from the middle virtually overnight, if mix stays wet and goes sour. I grow my young plants in loose sphagnum, straight, in very small pots; 1.5-2". The pots themselves sit in direct line of the grow room fan, drying fully within 2 days. I mist every other day, water heavily once a week, and once they come out of 2" pots, they are mounted or set in baskets with little or no media, often simply lined with live Tillandsia unesoides or loose coconut fiber. In fact tillandsias make such good companions for these tiny Oncidium relatives, I often drape a little unesoides or attach other small species to mounts along with them. Some species that are very scandent are usually mounted on branching, twiggy mounts they can freely climb.
If you can keep Tillandsia happy *and blooming,* I highly recommend adding some Tolumnia to the same growing space. Their delightful, reblooming clouds of flowers over very compact foliage are an excellent reward for attention to their specific needs as twig epiphytes. We expect to begin offering species and hybrids of Tolumnia and related genera in the next couple of years.
