- Choose plants that seem especially healthy and not stressed from drought, disease or other factors.
- Let seeds dry on the plant as long as possible. Observe plants to discover at what point the plant would naturally drop its seeds and collect them then.
- Seeds typically are embedded in pulp, pods or capsules. Harvest seeds on a sunny day after the dew evaporates. Remove all pulp and fiber from their surfaces.
- Dry seeds in a well-ventilated place on newspaper, paper towels or screens for about a week.
- Store seeds in glass jars in a cool, dry location.
- Cut a 6-inch piece of stem off the plant. Usually the tip of a branch or stem will do, but if the plant is blooming, cut in a bit deeper.
- Take cuttings from different parts of the plant to avoid creating holes in the foliage.
- Remove flowers and cut the stems into 4- to 6-inch pieces.
- Make a clean cut at the bottom of the stem and remove all but a few leaves at the tip end of the cutting.
- Dip the cut end into a rooting hormone.
- Place the cutting into a 2- to 4-inch plastic nursery container filled with fresh potting soil.
- Place the container inside a clear plastic bag, keeping the plastic away from the cutting and securing the opening of the bag with a twist tie or rubber band.
- Place the bag in filtered light, not direct sun.
- Water when soil feels dry to the touch.
- When roots form, remove the plastic bag and set plants in a protected location with filtered sun.
- Begin a mild fertilizer program applied at half strength every two weeks.
- Transplant the young plants into a larger pot when roots start coming out of the drainage holes.
The best time to divide plants depends on the region where you live. In cold regions, early spring is usually the best time. In climates with mild winters and hot summers, fall may be a better time to divide.
— Choose a cool, cloudy day to divide and replant. If the ground is dry, begin by thoroughly soaking the soil around the plant.
— Let the soil drain while you gather a shovel, garden fork, pruners and sharp knife.
— Trim the leaves or stems about 6 inches to make handling easier.
— Dig up a clump of the plant.
—Place the entire clump on a tarp in a shady spot, and check to see if any sections naturally split off. Some perennials have roots that are easy to separate; others are tangled and may need to be pried apart with garden forks. Still others have fleshy roots that must be sliced into sections. Prune away dead and damaged tissue, and make sure each section has a portion of roots and leaves.
— If you are giving the divisions away, place them in containers and pack moist soil around the roots. Water them and keep them in a cool, shady spot.
— Plant divisions as soon as possible. Set the plants at the same depth they were in the original bed.
— Water the new divisions well, and keep them well watered throughout their first year.
Source: National Gardening Association