Not having a pseudobulb implies that Tolumnia orchids need to be watered frequently but they live in dry climates.
This is how oddly strange they are, but ever so fascinating.
Without a storage unit, they will shrivel up and die within a few days if left dry too long. Yet when watered, their tiny sensitive roots are prone to root rot if kept wet overnight.
This dry/wet combination is extremely crucial to their culture and growth and is easiest to understand that when you look at where they grow.Tolumnia orchids grow around many islands of the Caribbean and West Indies.
Some Tolumnias grow indigenously on one crucial island, either Cuba, Jamaica, Bahamas, Haiti, Dominican Republic, Hispaniola, while other Tolumnia species are found on all of them and can reach as south as the northern tip of Brazil.
There are about 30 species in all, growing in between the sandy beaches but not yet penetrating the forest jungles. They like to be somewhat near—but not too close—to the ocean.
They thrive in dry soil and humid air.
I want you to imagine a vacation spot on a tropical island, with constant warm breezes as you tan in the sun on the hot, salty beach. In the afternoon it usually rains, but a quick, soft rain that does nothing to cool down the hot and sticky weather, but raises humidity quite a bit.
As you walk back to your hotel from the beach, you see the scarce coastal vegetation slowly start to thicken with more palm and coconut trees, short grasses, and thicker shrubs. As soon as you reach the city streets, less than a few miles away, you’ll find Tolumnias growing closer to the ground but still epiphytes. They will attach to tiny tree branches and small twigs (not the main tree trunk) and also rocks, classifying them as both epiphytes and lithophytes.
They usually grow under larger growing plants, so even though they like the sun, the shady hours of the day that sun is dappled upon them is incredibly long and the rays are fierce. This classifies them as low light orchids, but if left in brighter light they also grow well.
Adapt them slowly, and they’ll grow fine.
Since they have a rhizome that travels out, they are also classified as stoloniferous plants,
which means “A horizontal stem that is located above the ground and usually produces adventitious roots and vertical stems at the nodes. Stoloniferous refers to a plant that bears stolons.” (Source
Stoloniferous usually comes to mind when we think of impenetrable grasses, or worse—weeds, that form a thick cluster of growth.
About weeds—I have to mention this fact which I found rather funny. Around 1950, one grower of Tolumnia orchids, Gooldale Moir, was fascinated by these orchids. His colleagues, however, thought they were weeds and didn’t share his passion. Much to the contrary, they thought he could spend more time researching other orchids. By 1970, he was a well-known breeder and published articles about Tolumnias. Weeds are sometimes not what we think. Source: Steven A. Frownie and National Gardening Association
in the book Orchids for Dummies which you buy here
. (Affiliate Link). Despite the book’s name, which I find personally offensive, the information in the book is really good.
As so-called “weeds”, Tolumnias will do the same and grow in impassable, dense clumps. Even though the rhizome travels out producing vertical clusters, they never travel far. This turns them into a thick, impenetrable cluster of leaves, hardly ever outgrowing their pots.
For us as indoor orchid growers, that’s great because they save space. These tropical-island orchids love humidity, which is why they don’t need a pseudobulb. When it rains, the water quickly trickles off their tiny roots, leaving them to dry.
The year-round higher temperatures and the constant airflow coming from the ocean maintains them dry most of the time, even though it rains almost daily. If it doesn’t rain in a few days (four or five), these orchids will wither quite quickly.
The secret to having these orchids grow well is to keep the humidity high around them.