Opening Hours of flower market
The flower shops on Flower Market Road in Mong Kok open mostly normal business trading hours. As they are originally wholesale and later retail to local public outlets and not so much a tourist destination the shops tend to just be regular Hong Kong shopping hours.
In Hong Kong of course that is longer than in some other countries so you can
Each flower shop on in the flower market is independent and so when they open is up to the owner, the road itself is open 24 x 7 as it is a public road.
Most shops have staff there early to start accepting deliveries at around 7am, so if you are jet-lagged traveler awake at this hour you will find the shops busy, but mostly unloading boxes so it isn't the best time to visit and they are not functioning as shops yet. Later in the morning when deliveries have been received, outgoing bouquets have been sent, and before lunch, is the most relaxed part of the day here. Officially the majority of shops state their opening times as 9:30am.
In addition shops still stay open after office hours so that people leaving work can still buy flowers, and the shops don't close until 7:30 pm in the evening or when the customers start to stop buying!
Flower Shops are generally open 7 days a week, including public holidays such as Christmas and Easter. However during Chinese New Year the shops will be closed on at least the first day of the new year as all the vendors will have been working very hard during the Lunar New Year Fairs, such as that one in Victoria Park, which close at midnight on New Year's Eve.
So in summary flower shops on Flower Market Road are generally open:
09:30 - 19:30 - Monday through Sunday, except for first day of Chinese New Year