Dendrobium or Phalaenopsis?
They are two separate genus Mike.
I assume you mean Dendrobs as Phals dont have canes, I have plants that are about 15cm to 20cm tall that have put out their first spike. The first one is usually kind of weedy looking, often with only 3 or 4 flowers. If you give the plant enough light, depending on the hybrid you can get 12 to 15 spikes in a year. I have some mature ones that have canes about 1 metre (3 feet) tall and with a diameter of about 7cm (2 inches?). They are in full sun and are almost constantly in flower.
Lots of light is fine for Dendrobs but don't go giving them too much too quickly.
Actually, there is a species called Dendrobium phalaenopsis (which may or may not be a synonym for D. bigibbum). According to Schelpe and Stewart's "Dendrobiums an introduction to the species in cultivation", the smaller form (called bigibbum) has pseudobulbs that mature at 40 to 60 cm, while the larger form (called phalaenopsis) has pseudobulbs that can go to 120 cm.
Of course, if you have a D. phalaenopsis hybrid, all bets are off
I'm pretty sure what I have is a true D. Phalaenopsis. I'm just a little confused because you say the canes are mature at 120 cm. Yet I have a Keike less than 5 cm long, flowering. Just a single flower about 1 cm long on a 4 cm flower stalk. I'll post some pics when it opens, which will be soon.
Mike - I don't doubt you for a second. I've had some plants labeled 'bigibbum' that flowered regularly with 6" or 7" canes. So I guess it boils down to the book's definition of 'mature' as opposed to 'flowering size'. It may be that the sizes in the book are the maximum that can be expected under perfect (wild) conditions but that plants will flower when they are much smaller. Experience would certainly say so.
Edit: Now that I'm thinking about it some more, it may be that orchidists have bred dwarf varieties of the plants - not everyone is going to have room for a 120 cm cane
Your probably right Merlin. I just didn't expext flowering size to be shorter than my thumb.
Anyway, the bud has swelled up to twice it's original size so it should open anytime now. To date, this will be the first Dendrobium to flower in my lowland terrarium. The only others I've had are a Paphiopedilum and a Phalaenopsis. I'm really excited.