Perennial seeds with thin seed coats can be started at any time of year, preferably in mid-summer. This gives them time to germinate and grow large enough to be established before winter sets in. This type of perennial can also be planted in late fall and will have enough stored energy to survive the winter, provided you place plenty of mulch around the root area.
Perennials with thick seed coats, like hibiscus, need time in the winter for the hard outer seed coat to soften. This process is called stratification or &8216;cold treatment.&8217; You can use the same principle in your refrigerator to start your hard coat seeds. Place the seed in moist soil in a sealed bag, and keep it in the fridge for 3-5 weeks. (The fridge is better than in the freezer.) Inspect the package every week to see if any seeds have germinated early. If so, go ahead and plant!
Chipping the seed is also beneficial - perennials like morning glories germinate best if you nick the hard outer coat of the seed. I use a file or rough stone to gently scratch the outer seed coat.
I received a great guide from the Thompson Morgan Seed Company, called &8216;Successful Seed Raising.&8217; I use this guide to help me germinate all my perennials and other seeds.
I hope this information will help you begin a perennial-starting adventure: it's always exciting to grow plants from scratch; And remember - I can be asked any plant question at the Bloomington Community Farmers' Market on Saturday mornings downtown!