Question
I have what I believe is a crooked willow cutting that I took from a floral arrangement that was delivered to our office.  It was putting out new growth so I wanted to see if I could root it.  It's doing quite well in a glass of water right now.  I live in a rental house and don't really want to "donate" it to my landlady.  Can I grow it for a period in progressively larger flower pots?  thanks for your assistance.

Answer
Yes you can grow it in pots for a while. Usually the pot size (height) is 1/3 the height of the plant. When the tree gets three times the height of the pot then you will need to transplant it into a larger pot. Willows grow fairly fast so in a few years the tree will be too large for a pot that you can handle. I would make sure the pot has holes in the bottom so the water can drain. I would use a potting mix that will hold moisture. Keep the soil damp but not wet. For a shot few years this can be done. You may need to prune the tree back if it gets too tall.