As a Toronto florist who's been at this flower game for a looooong time, sometimes I forget that people not in the industry don't always know what we're talking about! If you've been wondering what the difference is between a bouquet and an arrangement, you are not alone- I do get asked this often.
So, here is the essential primer:
A bouquet is a collection of flowers that the florist arranges in their hands and then ties in place. Because they are made by holding the stems in our hands these are often called "handtied bouquets". The flowers are not in a container when you purchase them, so you or the recipient will need to find a suitable vase or container to put them in when they are received. Flowers can go only a very short time (pretty much only minutes) without a water supply, so we florists will usually ship the bouquets out for delivery with a temporary water source to keep the flowers hydrated for the few hours they are out for delivery (although, a LOT of florists don't provide this- I always do, because it keeps them fresh longer and makes a massive difference to how long they will last).
Pros to sending a bouquet: you aren't purchasing a container, so all the $ will go on the flowers, meaning you get a little more for your buck plus the person you are sending to doesn't have to keep a new container.
Cons to sending a bouquet: In my experience most people only have a couple of vase options in their homes and chances are they won't be the right shape or size for the bouquet you've sent them, so the bouquet doesn't get displayed at it's best. You are relying on the recipient to properly read and follow the care instructions we florists send to make sure they get the flowers properly into their new vase.
An arrangement is a collection of flowers and greenery that we florists arrange into a container, so in essence it's a bouquet already arranged in the vase for you. The final product is complete and all the lucky recipient needs to do is unpack, top up the water and enjoy- no fussing finding a vase and having to cut anything down to try and fit properly. Because the florist is making the piece to completion there is more creativity possible in the design, which will always result in an arrangement being more impressive than a bouquet.
Pros to sending an arrangement: The recipient doesn't need to do any work other than topping up the water, no fussing about trying to find containers or fiddling about with cutting the stems down. The flowers also always look more polished and will be more of a special gift.
Cons to sending an arrangement: You are going to be paying for the container as part of the cost of the design.