Answer: Many perennial seeds can be planted during the summer and fall and allowed to sprout and grow according to their own schedules. This in effect mimics nature's way of allowing plants to self sow. The success rate using this method, however, is poor compared to started the seeds under more controlled conditions -- that's why each plant makes so many seeds just to ensure its own reproduction.
Each perennial has its own preferred conditions for germination, requiring particular temperature ranges, moisture levels and so on. Some even require a cold period followed by a warm wet period, or alternating freezing and thawing temperatures. Having said all that, seeds are meant to grow and if your friend assured you these were reliable for her, they probably will grow for you, too.
To maximize their chances, you should prepare a weed free area, loosen the soil and add some organic matter such as compost, rake the soil smooth and sprinkle the seeds. Water gently and keep the area weeded. Alternatively, you could simply strew the seeds in areas where you would like the plants to grow. If the areas you select are suited to the plant's soil and light preferences, they may actually "take" with no further help from you.
Good luck with your seeds!
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