Late seeded perennials.

[Elbowrust]

I've found lots of information on when to plant perennial seeds but nothing on the last date to seed perennials before it's too late to get decent growth. I'm in zone 6, Canada, and I probably have 3-4 months before it starts to get cold. How long will it take for seedlings to harden off and survive a winter?

[applestar]

"Perennials" is pretty vague and vast ... which ones were you thinking of growing? Some require cold stratification to germinate or cooler spring temperatures to sprout and grow as seedlings. Some need to establish deep root system in the ground and/or harden the upper growth into semi-woody or dormant state to survive the winter.... but some might be kept in containers and overwintered in protected area for planting next spring.

[Elbowrust]

Sorry I should have been more specific. I want to plant purple sage, hardy hibiscus and echinacea. They will be seeded in pots.