Q.My dahlia is producing dead flower buds.
Last year was the 2nd year after I bought them and had a full flowering dahlia with beautiful red stars. This year I have 2, and they are 1 meter high. The flower buds are black and haven’t had a single flower yet. What’s wrong with them and what can I do?
This is very common with phosphorous and potassium deficiencies. Even more so in container, but it can happen in soil, too, if they aren't fertilized every year. This article will give you more information: https://www.gardeningknowhow.com/ornamental/bulbs/dahlia/dahlia-care-grow-dahlia-plant.htm