Dahlias are one of the most versatile flowers for the border in summer. The blooms range in color from pure white all the way to dark shades of brown and purple and and shapes are equally varied from small single types to huge balls of petals. In addition dahlias can bloom for several months from summer on into fall and even up to the first frosts, but this depends on the correct treatment as Martin Cole explains in his article which I found on the Gardening Step by Step website.

To my mind, one of the greatest strengths of dahlias, is that they can go on flowering from mid-summer right until the first frosts.
Depending on where you live, that could mean that you can have dahlias in bloom for three, four or even five months.
However, the most important word in that first sentence was can.
Taking care of dahlias: purple cactus dahlia close up
Once you know how to grow dahlias, they can flower for extended periods but only if you, the gardener, help them do so.
Taking care of dahlias involves the usual necessities of feeding, watering and mulching. But to get prolonged flowing, you need to dead head.
And it can be a little bit harder to dead head dahlias than it is for most flowers, unless you are aware of one important fact ? how to identify the spent flower head.
(I have to say, I can never think of dead heading, without thinking of the Grateful Dead. But maybe that?s just me.)

The two step tip for dead heading dahlias

In case you don?t know, dead heading is simply a matter of removing spent flower heads.
This prompts the plant to produce more flowers, because removing the spent flowers deprives the plant of the potential seeds that evolution is driving it to produce.
Dahlia red

Step 1 ? Identify the spent flower

This is what makes dead heading dahlias a little bit tricky.
The problem is that once all the petals have fallen from a spent dahlia, the hard green part at the base of the flower (the calyx) closes over and what is left looks very much like like a bud.
So unless you know how to tell the difference between the buds and the remains of the spent flowers, you can end up removing the very buds that you are trying to induce into flower.
Fortunately, it is pretty easy to tell which is which when you know how. So here?s the trick:
The buds are rounded and the dead heads are cone shaped.

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