From a great book called Gardening Month by Month in British Columbia by Alison Beck and Marianne Binetti
August is a good time to propagate plants. Taking cuttings and gathering seeds are great ways to increase your plant collection and to share some of your favorite plants with friends and family.
Now is a good time to divide some perennials and to note which of your plants will need dividing next spring. Look for these signs that perennials need dividing:
Ø The center of the plant has died out.
Ø The plant is no longer flowering as profusely as it did in previous years.
Ø The plant is encroaching on the growing space of other plants.
Perennials, trees, shrubs and tender perennials that are treated like annuals can all be started from cuttings. This method is an excellent way to propagate varieties and cultivators that you really like but that are slow or difficult to start from seed or that dont produce viable seed.
There is some debate over what size cuttings should be. Some people claim that smaller cuttings are more likely to root and will root more quickly. Others claim that larger cuttings develop more roots and become established more quickly once planted. Try different sizes and see what works best for you.
Always make cuttings just below a leaf node (point where the leaves are attached to the stem).
Many gardeners enjoy the hobby of collecting and planting seed. You need to know a few basic things before you begin:
Know your plant. Correctly identify the plant and learn about its life cycle. You will need to know when it flowers, when the seeds are likely to ripen and how the plant disperses its seeds in order to collect them.
Find out if there are special requirements for starting the seeds. For example, do they need a hot or cold period to germinate?
When collecting seed, consider the following:
Ø Collect seeds once they are ripe but before they are shed from the parent plant.
Ø Remove capsules, heads or pods as they begin to dry and remove the seed later, once they are completely dry.
Ø Place a paper bag over a seedhead as it matures and loosely tie it in place to collect seeds as they are shed.
Ø Dry seeds after theyve been collected. Place them on a paper-lined tray and leave them in a warm, dry locations for one to three weeks.
Ø Separate seeds from the other plant parts and clean them before storing.
Ø Store seeds in air-tight containers in a cool, frost-free location.