Grow Next Year's Annuals From the Cuttings of This Year's Plants
Planting annual flowers can be a frustrating endeavor: You spend a lot of money (either on seeds or starts) and invest all that time in planting, just to watch them die at the end of the season. That's why you should propagate new plants every year from cuttings.
Propagation is more efficient and selective than growing from seedThere are two good reasons to learn how to propagate from cuttings, and the first is efficiency. It's faster and cheaper to grow your own duplicate plants from another one of your plants, whether you grew it yourself or paid for it. Yes, you could grow more from seed, but there's all the risk of failed germination, and the time required as well. Propagation is faster, by many weeks.
The second reason is selectiveness. Choose the plants you really like and that are doing well, and propagate those. You're choosing to create dupes of the plants best suited for your yard. Not for nothing, but you can do this at the end of the season, bring those cuttings inside for the winter, and baby them along so that you'll have a plant ready to go in the spring. At that point, you can take cuttings from this new mother plant and have starts ready for the garden in a few weeks. This is actually how commercial gardeners keep mother plants for propagation in their greenhouses all winter long.
How to propagate from cuttingsIt's so simple that it's honestly dumb we aren't all doing it. The first step is choosing the right plant. You want one that is doing well, and that you actually like. At that point, you want to take a cutting of 3-4 inches. Some notes: You want to use a clean pair of scissors or pruners. Spray them with vinegar, Lysol, or a bleach solution beforehand. Once you have the cutting, strip all the leaves off the bottom half of the cutting.
You're going to dip the last two inches in rooting hormone. This is a powder you can buy at the nursery, and although cuttings sometimes do OK on their own, this will stimulate root growth, which is what we want. Once you dip the cutting, you can put it into your potting mix. I use plug trays, so it's easy to separate them and plant them when they've established themselves. These trays need to be watered often enough that the soil is moist but not wet. Within a week or two, you should see growth, and within four weeks you should be able to either transplant the cuttings to larger planters or put them out in the yard.