I am strongly of the opinion that a quantity of plants, however good the plants may be themselves and however ample their number, does not make a garden; it only makes a collection.
Colour in the Flower Garden by Gertrude Jekyll (1908).
Plants don’t flower to delight humans. That is merely a bonus for us. Plants are genetically programmed to reproduce themselves and flowering is part of that process. Dead heading plants is therefore akin to contraception – preventing them from setting seed. In many cases, the plant will try again and set more flowers. That is what happens with annuals, perennials and repeat flowering roses. Removing spent blooms will extend their flowering season considerably. It doesn’t work for plants where flowering is set the preceding year (bulbs, rhododendrons and many other woody plants) but interrupting the process of setting seed can make the plant concentrate its energies on fresh growth and setting more flower buds instead. Annuals and biennials die after setting seed. Some plants can set so much seed that they weaken themselves and may eventually die (some rhododendrons and pieris, for example). Plants which are sterile often flower extremely well because they never get past that optimistic first stage of procreation.
First published in the Waikato Times and reprinted here with their permission.