I broke my dahlia plant off at the ground level. Will it regrow this year? Is there a way to grow the top I broke off?
We are very sorry to hear that your dahlia has broken. These plants, which have wonderful, showy blooms are tuberous rooted perennials in the aster (Asteraceae) family. They benefit from shelter from strong winds and taller varieties usually need staking. They will not survive Toronto winters, but the tubers can be dug up and stored overwinter.
Dahlia’s can be propagated from seeds, tubers, or cuttings. Depending on where the stem broke, how large it was when it broke, and how you have stored the broken part of the plant (if it is still fresh and has not been allowed to dry out), you might have success in treating it as a cutting. Ideally it should be dipped in rooting hormone, but you could also skip this step and place it directly in sterile soil. You might find this video from the Portland Dahlia Society helpful: https://www.youtube.com/watch?v=i2hFvm6MMig/. You have nothing to lose by trying and might wind up with a second dahlia plant!
Dahlias develop eyes and sprout from the neck which connects the tuber to the stem. They are reasonably resilient and assuming that your stem broke off above this area (which is likely if it broke off at ground level), it will likely develop new eyes and re-sprout, and your original plant will still provide you with blooms this year.
Happy growing!
June 2, 2022