Larkspur always have a special place in my garden. It’s not that I have fond memories of them or anything – it’s that they’re one of the first hardy annual flowers that I was able to successfully grow. With their carefree habit, they’re super easy to sow and to use as cut flowers. As always, make sure to do your research before planting. Larkspur are toxic, so make certain to keep your kids and pets (and everyone else) safe while in the cut flower garden.
Here in Kentucky (zone 6b/7), I direct sow the larkspur seeds into a prepared garden bed in the fall around the end of September. This is a good time because the temperatures are nice and cool with highs usually in the 70s(F). Before surface sowing the seeds, I put the packet into the fridge for about a week. This seems to hit any cold stratification requirements that they need.
Larkspur seed germination can be slow. In my yard, it can take up to about 4 weeks. Even then, it may be really difficult to identify the seedlings because they resemble the seedlings of many other garden weeds. It isn’t until months later (once they put on sizable true leaves) that I finally get a better idea of how well the plants are actually doing.
By the time the first frost arrives in the fall, the larkspur have several true leaves. These plants will remain small and close to the close throughout the winter and the extended periods of cold weather. Once spring arrives, they’ll begin to stretch taller and bloom.
I’ve had success with larkspur here in my yard without protection from any kind of row cover. However, the plants will be impacted by the severity of the winter temperatures. Last year, the entire patch survived unharmed. The year before, I lost every single plant to cold. Whether or not you’ll need the protection of a row cover or low tunnel will completely depend upon the conditions in your own garden. It really is a process of trial and error.