Dendrobium pleianthum

Also known as: The Rich or Grastidium dolichocaulon Exochanthus pleianthus Exochanthus dolichocaulos Dendrobium dolichocaulon in the subfamily: Epidendroideae

General Information

The Rich is a large sympodial warm to hot growing epiphytic or terrestrial orchid belonging to the sub family Epidendroideae.

Plant Description

Sympodial. Grows to 91-122cm. Each new growth has numerous lance shaped leaves that grow to 13-20cm long. Pseudobulbs grow to 86-114cm

Substrate(s)

• Coarse

Care Notes

These orchids like to be watered regulary, especially during warm weather, and prefer a well draining mix or also do well mounted, provided they can be watered daily or even many times a day.

These are quite a forgiving orchid, there are no special requirements to get this orchid to flower, just good care and consistent conditions. Larger plants may be more fussy and can react poorly to change; a poorly timed repotting, a pest infection or an unusually hot day can set them back for a couple of years. However, even plants that have been treated poorly can thrive, and if they are set back they often recover much stronger then they would otherwise be.

Climate

Grows at low to high elevations. Rainfall ranges from 112mm to 424mm per day, heaviest in September and lightest in February. Humidity ranges from 80% to 87%, highest in September and lowest in April. Temperature ranges from 17C to 26C, highest in March (18C to 26C) and lowest in January (17C to 25C).

Watering

These orchids prefer a constant supply of moisture, with a slight drying out between waterings. Saucers can be placed under pots to retain moisture during hot weather, however the saucers should be removed or let to dry every 1-2 weeks to prevent rot. Keep an eye on the plant especially in hot weather and look for cues of under/overwatering and adjust accordingly.

Keep moisture levels up during hot weather as the plant is prone to dehydration

Fertiliser

Apply liquid based fertiliser per recommended directions. They can benefit from a high phosphate fertiliser leading up to flowering season, followed by a high nitrogen fertiliser when new growth appears, and a balanced fertiliser in other times. These orchids can also tolerate slow release fertiliser applied 1-2 pellets per cup (250ml) of media.

Use balanced fertiliser year round. Apply fertiliser regularly at half strength year round.

Potting

These plants can be sensitive to repotting though should not require repotting regularly. Repotting should be done when the mix has broken down to the point that it doesn't absorb water or holds onto water for far too long, usually the plant shows a decline in growth as well.

The mix should be free draining, with a blend of 30% inorganic ingredients such as coarse sand, gravel or perlite, mixed in with about 70% organic ingredients such as peat, leaf litter or decomposed bark. Avoid commercial potting mixes as they can vary wildly and may contain "wetting agents" that can hold onto water for loo long, causing rotting and stunted growth.