Haha, well sure Sugar, wherever you can. I should have said that I bleach the bathtub before using it, haha! I use the bathtub because I am usually doing up a whole bunch of flowers and I wash them while the stems are attached. Then to let them drip dry, so they are not flat, I tie them in bunches by the stem (or use elastics), leaving a loop to go over the shower curtain rod or towel racks as I have some in the tub enclosure. One of the best things I have is one of those bath seat benches that we used for my elderly mother. It naturally had a bunch of holes in the seat, for drainage purposes, so I can stick the stemmed flower through the holes to dry. For a lot of flowers like tulips and roses, you don't want to put them flat while drying as it can misshape them.
You could wash them in a laundry tub too, I just find this method easier. Whatever works!
Most of these flowers dry fairly quickly. You should always do a colour wash test first. I have yet to have any issues with colours bleeding out when washed, but test to be sure.
A little advice, if you are going to need a lot of flowers, instead of getting individual stems, get the bouquets that consist of several attached at the stem as a bouquet, it works out a lot cheaper and they cut easily too.