Hi J and G,
I do not think that they are petals. The flowers for the offerings and garlands are sold in another way. Most probably it is rice - hold in big sacks.
White flowers sold are usually jasmin as you can see here:
https://www.trekearth.com/workshops/...hoto226162.htm
and here:
https://www.trekearth.com/workshops/...hoto226161.htm.
Have a nice weekend
M