Dendrobium MacPerson, the first of my plants to have flowers in 2015

Dendrobium Alex MacPherson is the hybrid of Dendrobium Salak and Dendrobium helix.  Den. Salak is a hybrid of Den. stratiotes and Den. discolor.   In this particular plant the strength of the heritage of the Den. helix parent can be noted in the color of the flower.  The flowers of this hybrid resemble mainly the flowers of the Den. helix parent, although they are smaller and more numerous in the inflorescence than the flowers of my plant of Den. helix.

In this particular plant the flowers are crowded in the inflorescence which makes it difficult to take good photos of individual flowers.  I cut some flowers from the inflorescence so I could show the variation on petal orientation between different flowers.  There is also some very slight variation of color between individual flowers.

A few years back I brought a number of plants of this species because they were labeled Den. helix.  As they bloom during the year I document the differences between the different clones.  In this one the pink is confined to the sepals while the petals are orange.  Some flowers show a bit of orange color on the sepals.  

Dendrobium Alex MacPherson

Some years ago I brought a number of plants of what I thought were Dendrobium helix from several local vendors.  When the plants bloomed they all turned out to be Dendrobium Alex McPherson.   This hybrid is common in local collections and shows wide variability in the colors of the flowers.  The plant I have range from mostly pink with coopery petals to almost all cooper color.  The orientation of the petals is highly variable, even in a single inflorescence.  The number of flowers in an inflorescence can go from relatively few to many densely packed flowers.  I have found it easy to grow under my local climatic conditions.  However the inflorescences are easily damaged by thrips.  When the thrips are swarming, normally during the mango tree blooming season, the inflorescences of this hybrid are often attacked and severely damaged.  During the rest of the year the flowers are long lived and stay in good conditions for several weeks.  The flowers lose color as time go by and an old flower can be a pale picture of a recently opened flower.

Dendrobium Alex MacPherson, It was labeled Den. helix when I brought it.

A few years ago I  brought a number of plants labeled Dendrobium helix.  When this one bloomed it turned out to be Dendrobium Alex MacPherson, a hybrid.   It parents are Dendrobium Salak (Den. Stratiotes x Den. undulatum) and Dendrobium helix.

Dendrobium helix P.J. Cribb 1980, some notes on its care

This species is from New Guinea, it grows in the coastal lowlands.  It has proven an easy species to grow under my local climatic conditions.  The largest canes of my plant have reached four feet tall but I am sure it has the potential to grow even larger.  It produces inflorescences intermittently during the year but flowers most realibly in late autumn.  The flowers of this particular clone are orange and have a purple lip.  Here are some observations on its growth and culture.

Light:  My plant grows best just under the sarah cloth where it is exposed to the strongest light short of full sunlight.  Unfortunately the canes grow right up to the shade cloth and inflorescences can grow into the cloth and become damaged or deformed if the plant is not lowered to allow them to develop normally.

Temperature:  It grows well under the local temperatures.

Watering:  Most of the year the local rainfall supplies all the water this plants needs, only in the driest months do this plant has to be watered.  Watering it once a week in the dry season is enough to keep the plant healthy.

Fertilizer:  This plant gets fertilized only when it is producing new canes.  In its growing season it get a high nitrogen fertilizer.

Potting:  It is growing in a wire basket that I made specially for this plant.  The media was bark, but it decayed away years ago.  The plant is growing on top of the remains of its own old root ball.  Every year a new flush of root growth from the new canes grows over the basket and the old roots.  I have also used plastic pots and they work well as long as they have plenty of holes and the media is open.  Clay pots also work well with the added bonus that their weight helps keep the plant upright when the mass of canes becomes too heavy.

Pests:  Thrips will damage the inflorescences and the flowers.  Slugs will eat the canes when they are young and tender.

Notes:  My plants grow best if they are in an open media that allows plenty of air to reach the roots.  The best media for this species in my garden is stones or very hard bark that decays slowly.