It is done to keep plants looking attractive and encourage more blooms, whether in beds and border, containers or hanging baskets.
Reasons for deadheading
Most flowers lose their attraction as they fade, spoiling the overall appearance of beds, borders and containers, and are best removed. However, there are other reasons:
- Regular deadheading directs energy into stronger growth and more flowers. Once the flowers are pollinated; seed heads, pods or capsules form at the expense of further growth and flower development
- It can prevent plants with numerous petals, such as peonies, some camellias and many roses, scattering debris widely
When to deadhead
Remove the spent flowers as soon as they look scruffy.
Some plants do not need deadheading. Typically fuchsias, bedding lobelia and salvias either don't set much seed or neatly deadhead themselves.
Do not remove the faded flowers on plants that produce seed loved by birds, including Rudbeckia, cornflower and sunflower.
There is no need to deadhead rose cultivars that bear hips or other plants that bear berries in the autumn
Leave plants that have ornamental seeds or fruits without deadheading; examples include alliums; love-in-a-mist (Nigella), stinking iris (Iris foetidissima) and bladder cherry (Physalis alkekengi).