Some orchids, such as this species, are very straight forward to grow and always flower reliably.
This large growing Oncidium species is native to Central America where it is found as an epiphyte in dryish forest from about 500 to 1500m altitude. The plant grows new growths rapidly during the summer and then long spikes from the new pseudobulbs in the spring. Each metre long flower spike with side branches carries up to fifty bright and long lasting flowers.
We have seen the closely related species Oncidium spaculatum growing high in trees around Laguna Yaxha in Guatemala where they are exposed to bright sunshine and long dry periods. They cope with these tough conditions by growing a mass of roots which can collect and store a lot of water from rain or dew when it occurs. As a result plants are easy in cultivation and we have had specimen plants with more than twenty flower spikes. Oncidium wentworthianum is smaller growing than Oncidium sphaculatum and has smaller spikes and so is all around easier to accommodate in a collection.
We grow this species in Warm Americas (Min 15C) where it gets well watered in summer but a dryer winter after the bulbs have matured in late November. However we never let the bulbs shrivel.