When I talk about sowing biennial flowers, I will be the first to admit that I use the term “biennial” very loosely. In general, the term biennial should be used to refer to plants that take two seasons to grow and bloom. However, I tend to call things “biennial” when they may be truly perennial. Either way, of all the seeds I’m planting into trays today – I treat them the same. I sow the seeds around the middle of August, then transplant them into the garden around the first week of October. They then overwinter and bloom the following year. I wish I could be more helpful in explaining my methods, but I too, am always learning!
This year, I’ll be attempting to grow Bells of Ireland again. Here in zone 6b/7, growing bells of Ireland from seed has really been a struggle. First, you’ll need to get the seed to germinate. I’ve found that I get decent results by putting the seeds in a moist paper towel in a zip bag. I then put the bag in the fridge for 2-3 weeks. After I remove it, I surface sow the seeds into a tray. Germination seems to take forever, but it eventually happens. 
Canterbury bells are another favorite of mine. They germinate much easier, and don’t seem to require any cold treatment – just consistent moisture. When they first germinate the canterbury bells seedlings are very small. It’s extremely important that you protect them from slugs and other bugs. Since I start all of my seeds outdoors, this means that I put my seedling trays under a layer of insect barrier row cover. 
Verbascum flowers are technically a perennial, but I find that they produce tall flower spikes if you start them early enough. In the future, I would love to find a permanent home for these.
You’ll find that these also germinate very readily. Since verbascum seedlings are especially tiny, it will be important to space out the seeds at sowing. I’m terrible at this, and often find myself planting huge clumps of plants instead of individual ones. 
Last, but not least, is dianthus. This year I’m growing several types. While sweet william flowers are a true biennial, I’ll also be experimenting with carnations and dianthus pinks. In the future, I’ll also be direct sowing some additional flowers for next year’s garden. Thank you so much for reading!
