Answer: First of all, different plants have different requirements for seed starting--some need light to germinate, for example. Most importantly, some perennial seeds need a pre-treatment to improve germination--for example, some will need to be chilled for a certain amount of time, to mimic the chilling they'd get if they remained on the ground over the winter and sprouted in the spring. So it's best to research each type individually. Seed packets will give you specific instructions.
Although you can sow perennial seeds directly into the ground, I prefer to sow most seeds in containers, so I can nurture them along until they get to a good size for transplanting. Many perennials are slow growers at first, and are easily overrun with weeds in the garden. You could also create a special "nursery bed" in your garden, where you sow your seeds and/or grow out your transplants. It can take several years for some perennials to reach flowering size, and you may not want to put them in your flower beds until then.
Q&A Library Searching Tips