Q.Snapdragons
When I cut off the stalk of dead blooms, can I then plant the round balls (assume it contains seed} to get more plants?
To save the seed, wait until the balls, or seed heads, turn brown. A hole will start to open up or you'll seed a crack forming. While they are green, the seeds aren't ripe yet. When you should sow the seed depends on where you live as the seed will not usually survive a cold, zone 4-5 winter. I'm in 5b-6a and usually scatter the seed in the fall. Actually, I don't harvest seed until the fall, removing the earlier spent bloom spikes before seed formation to promote further blooming.