This is a great time of year to make yourself some free plants from those you already have! This works well on every shrub I've tried it on, as well as raspberries and blackberries, and there is an air-layering method that can be used to propagate new trees using the same concepts. (See diagram below for a visual on this technique.)
To grow a new bush, simply bend a branch down to the ground and anchor it at a leaf node (where new leaves would emerge), adding a rock or brick on top to anchor the branch firmly to the ground (or a stake, as shown below). In spring, you should have a new plant ready for transplanting to another area of your yard!
A few tips:
Scraping the bark on the underside of the branch you're layering will speed along the process by triggering rooting hormone production.
To check for readiness in spring, gently tug on the buried branch. If there is strong resistance, a good root system has likely developed.
When a solid root system has developed, cut the branch, separating the new plant from its parent plant, but leave it in place another 2-3 weeks to allow it time to adjust to the sudden decrease in hydration and nutrition.
Be sure to water your new plant during this time if weather is dry.
Transplant elsewhere in your landscape, leave it where it is for later transplant, or pot it up and keep it where you can water it regularly until temperatures cool in the fall. I find fall to be the best time to plant or transplant young plants because this allows them time to establish a strong root system before the drought of the following summer. Younger plants put out in spring often aren't strong enough to survive prolonged dry spells.
Please feel free to share any of your own tips and insights, and any plants you've successfully layered using this or similar layering methods.