Cosmos are one of my favorite annual flowers. Beautiful and easy to grow, they bloom in a range of colors from white through pink and dark red. They set seed easily and often self-seed volunteer plants. However, you can also easily propagate Cosmos via cuttings placed in a jar of water in a windowsill. Why would you want to do this when growing then from seed is so easy? There are several reasons. If you have a plant that is particularly hardy and well suited to your location, propagating it by cuttings will give you identical copies of the plant. Similarly, if the blooms of your plant are particularly beautiful, you can multiply the plant this way. Just snip off of a tip of new growth, making sure you include a couple nodes on the stem. Fill a jar with water, then cut the stem with a sharp knife just below a node. New roots will originate from that node. Immediately place the cutting in the jar of water, in a windowsill with bright light. Within a week or two, new roots should form. You can then pot up your cuttings in soil or even plant them in the ground. Just make sure to water them until their roots get established.