Growing dahlias from seed offers a certain amount of excitement because there is no control over the final outcome. Actually, it is the bees that have the power over the final result. Perhaps there will be unprecedented combinations of flowers growing in your flower bed this summer? Plant the seeded plants in the border as soon as the risk of frost is over. Dahlia thrives best in a sunny position and well-drained soil. Dahlia is also a lovely cut flower.