Deadheading is aesthetic and productive. Removing the spent blossoms on your flowering plants keeps the garden looking attractive and encourages plants to rebloom, giving you more flowers per season from the same plant. Just pinch off a small dead flower or use garden scissors or pruning shears for larger stems or woody plants.
Some plants will not rebloom if you deadhead them at the wrong time. Forsythia and oriental magnolia must be deadheaded as soon as they finish flowering or they will not produce more blossoms. Hydrangeas are the same. Prune hydrangeas' spent blossoms just as they begin to fade or those are the only flowers you will see that season. According to the University of North Carolina Extension, other flowers that react favourably to immediate deadheading are flowering almond and quince, spiraea, pearl bush, sweet shrub and most spring-flowering plants.
Roses that bloom once a year -- that includes most heirlooms -- may be left to fade on the bush. The rose hips are attractive and provide good forage for birds in winter. Reflowering rose bushes benefit from frequent deadheading and will produce many more buds and flowers if it is done correctly. Be careful to preserve leaves as they make the energy for the plant. Cut or snap spent blooms at the swollen section on the stem just below the flower to encourage new buds. Use shears and cut on an angle for best results.
If plants go to seed they will stop producing flowering buds so deadheading delays this process and will usually preserve the vigour of the plant much longer into the season. Pansies, marigolds, zinnias, daisies, petunias, geraniums and calendula can be tricked into flowering rather than forming seeds by deadheading. Another benefit of timely deadheading is removing rotting vegetation that can encourage disease to take hold on a plant. So, what looks good is also healthy for the life of the garden.
Day lily blossoms past their prime look like rags so snap them off. There are many reblooming day lilies now that will blossom once or twice more during the season You do need to leave the yellowing stalks as long as possible in autumn to refuel the plant's bulbs with energy for a new season. Columbine and lady's mantle bloom early in the season and should be deadheaded to encourage new leaves and blooms. Yarrow, purple coneflower and salvias will remain colourful highlights in the garden all summer if they are deadheaded when their blossoms fade. The foliage plants that also produce flowers should have spent flower stalks removed to keep the leaves vigorous and bright -- these are plants like hosta, euphorbia and pulmonaria.