Flower essence first became popular by Edward Bach and have been copied and extended by many others since the early Bach flower remedy times in 1930. Any flower can be used to create flower essences and orchids or preferred by many for their higher vibration.
However - as a general rule always the flowers growing in your native country or current living area are best.
Orchids can be used live without collecting the flowers - just live amidst beautiful healthy orchids and you absorb the healing essence of the flower in your aura.