Deadheading is a term we use to describe the removal of spent or dying flowers.
The only trick to this is knowing how far down the stem to cut the flower off.
From The Stem
And generally speaking, you remove the stem from where it started as a shoot from the plant.
So if we’re speaking of removing a geranium blossom, then the entire flower stalk is removed right down to the main stem of the plant.
If we speak of removing a perennial bloom, then the same thing happens – the flower and the stem are removed right to where the stem joins the main plant.
In bulbs, remove the flower head and stem as far down into the foliage as you can go without removing foliage. You require that foliage to stay green and intact to provide the energy to the bulb for next year’s flower.