From 1 dahlia tuber (also named dahlia bulb) grows a large plant that produces as many as dozens of flowers. The more flowers you cut from the plant, the more new buds develop and thus the more flowers will bloom. Dahlias flower from around June/July through October and sometimes even November (until the first frost).
If you plant about 5 tubers in 1 square meter, you can sometimes harvest more than 100 flowers per square meter!
From 1 dahlia tuber grows a large plant that produces as many as dozens of flowers. The middle picture shows 1 plant from Zippity Do Da.