Dendrobium nobile and anosmum(deciduous) Care Guide

Dendrobium nobile and anosmum (deciduous) Care Guide

Dendrobiums of the nobile and anosmum types are small to large-sized orchids with a deciduous habit. They produce tall pseudobulbs (usually called “cane”) with thin leaves along the whole length of the cane. They require a cool rest winter period during which they drop leaves. The leafless cane will then produce flowers from each node along its length during spring.

Light: Bright position, away from direct sun. East facing window with a bit of early morning or late evening sunlight is acceptable, north window is ideal particularly in summer. Mid-day sunlight can burn the leaves. Grow lights can also be used as long as a cool rest period can be provided.

Watering: During growing season water when the potting medium is approaching dryness. When a new cane has fully developed (there will be a small rounded nub at the top of the cane and no further leaves will grow) reduce watering significantly. Only water enough to prevent canes from shrivelling during winter months. When flower buds appear, resume watering gradually.

Temperature: During growing season these plants are relatively tolerant of high temperatures in the UK as long as there is air circulation and mid-day sunlight is avoided. During winter dormancy, temperatures should be as low as 10°C until flower buds appear. Afterwards keep the plant in slightly warmer temperatures around 15°C to help flowers develop.

Feeding: Always choose a quality commercial orchid fertiliser diluted to manufacturer’s instructions - overfeeding can damage your plant. Feed every second or third watering during summer and once canes have fully developed and you have reduced or stopped watering, skip feeding completely until the orchid has flowered in spring.

Re-flowering: Flowering is directly connected to watering, temperature and dormancy period. As long as these needs are catered for and the plant is mature enough, your dendrobium will flower in spring as described above.

Re-potting: Dendrobiums prefer to be slightly root bound – it is therefore best to avoid overpotting your orchid. Due to its growth habit along a crawling rhizome it will eventually outgrow its pot – this is your clue to repot. Repot in spring. Use a pot only slightly larger than what is needed for the plant’s size.

If your plant is mature enough this can also be an opportunity to divide it by cutting the rhizome and repotting the separate divisions individually. Always aim for at least three mature canes per division.

New young plants (keiki) may develop on older mature canes. These can be separated from the mother plant when they have at least three roots three inches long and planted as separate plants.

Dendrobiums in nature are epiphytic – they grow attached to tree bark on branches and tree trunks. As such, their roots are always exposed to excellent air circulation and dry off quickly after a rain which helps prevent root rot. In our home conditions this means that we need to use a potting medium that suits our conditions and will prevent water-logging the plant for too long as well as prevent the plant from drying out too quickly.

If your home is on the colder side, high quality bark chips are the best potting medium as this will be airy and will not retain moisture for too long. If your home is warm year round, you will want to consider a mixture of bark chips and dried long fiber sphagnum moss. The sphagnum moss will retain a bit of extra moisture which will help the medium stay moist for a bit longer during hot summer months while the bark chips will ensure there is plenty of air pockets and circulation of air around your orchid’s root system.

This guide was prepared by @Orchivorous