|How do I do cold treatment for Thalictrum rochebrunianum 'Lavendar Mist' and Verbena bonariense. Can I somehow put them in the refrigerator rather than buried in the snow?|
|Some seeds can be chilled in the fridge to break dormancy, but Thalictrum (Meadow Rue) must be started outdoors. After danger of frost, make a seedbed in a shady place (such as the north side of your house). Sow the seed 1/8" deep in the moist soil, and cover the area with a pane of glass supported by a wooden frame. Check the bed often and water if necessary. The seeds take anywhere from 2-8 weeks to sprout, or they may lay dormant for up to a couple of years! It's ideal to sow the seeds in fallas soon as they are ripe (if you collect your own seed). Maybe you should try some seed in spring and fall, and see how they both perform.
On the other hand, Verbena bonariensis seed can be chilled in the fridge to break dormancy. Just mix seed in a plastic bag with some moist seedstarting soil and chill for 2 weeks before sowing. Start seeds indoors under lights about 8 weeks before your last spring frost (around May 15). You can also sow seed right in the garden once nighttime temps stay up around 50F. Have fun!