A giant in the Hoya world, imperialis can grow to be a truly impressive plant.
The leaves are typically 10 - 20 cm long but have been known to reach 30 cm on occasion! It makes 3 to 12 flowers that can reach up to 8 cm in diameter! The less flowers on each inflorescence, the larger each flower will tend to be.
It can be found in Southern Thailand, Peninsular Malaysia, the Philippines, and Borneo, where it grows as a terrestrial climbing vine 30+ feet long up to 600meters elevation. Above that it has been found as an epiphyte in the canopy of tall trees.
There are a few different color forms, Pink, Red, White, Palawan, and rauschii.
This is the Pink form.
All but the White (alba) form are different shades of pink to red and all are a greenish to yellowish white on the back of the flowers, which is cool. The flowers are very thick and substantial, and very impressive.
Growing note: We have found that despite its size, imperialis is very sensitive to low humidity and to cold and extra care should be taken to protect it from humidity under about 60 - 70 % or temperatures under 50 F for extended periods. I've seen them completely "melt" to almost nothing in just moments when first taken out of a humid greenhouse into dry conditions.