Removing the faded flower heads from shrubs and herbaceous flowers will maintain a tidy appearance, stop unwanted seeds forming, and may also encourage further flushes of flower.
Similarly bedding plants will benefit most from daily deadheading, as this often extends their life and encourages them to continue producing more flowers throughout the summer.
Generally it is a case of taking the flower head off as soon as it begins to begins to go over,and or start turning brown.
This will help to conserve the plant's energy by preventing it from setting seed.
Index finger and thumb, floral snips, scissors, or secateurs.
Different types of plants may require different methods of deadheading.
For example; Plants with masses of tiny flowers such as Alyssum or Lobelia just forget it!
Bulbs - Snap off the dead head from the stalk,and leave the stalk in place.
Plants with lots of short-stalked flowers such as Fuchsias and French marigolds - nip off the dead heads between index finger and thumb removing as much stalk as possible.
Lilies - Cut off seed pods after petal drop, leaving the rest of the stem to die down naturally.
Lupins - Cut back flower spike as seed pods commence forming at the base, (prune out the stalk to just above the leaves)
Lavender - Trim off flower-heads with secateurs or scissors as soon as the flowers lose their colour, his will encourage bushy side growth and keep plants compact.
Roses (hybrids) – use secateurs and snip off 150mm - 225mm (6"-9") of stem together with the dead head just above a leaf joint.
Repeat flowering roses - Cut back the flowered stem to just above the second or third leaf.
Floribunda roses should be deadheaded regularly so that the plant's energy is channelled into the other flower buds. Cut each flower off as the petals begin to fall.
For plants such as Pelargoniums snap off the whole dead flower head and stalk, where it grows from the main stem.
With Rhododendrons, or Lilacs, take care not to damage the small buds developing behind the flower stalks.
Finally: Place the dead flower-heads on the compost heap providing they are not diseased.