Dianthus, or pinks as they are commonly known, enjoy full sun and well drained soil and in return provide the gardener with a pleasant show of bright blooms through the summer season and beyond. Regular deadheading will result in strong blooms by redirecting energy back into flower production instead of seed production. In addition deadheading dianthus will keep flowerbeds looking fresh and manicured whilst providing good air circulation around the plants which reduces the risk of disease. With over three hundred varieties, most rockeries and garden beds contain dianthus.
Examine each flower and stem systematically and cut off any flowers that have died, lost their bright color or have started to wither and brown. Cut the flowers off 1/4-inch above the nearest set of healthy leaves. Snipping the flowers off at this point encourages the plant to concentrate on growing a lustrous new bloom instead of growing new leaves. Removing the dead blooms encourages the remaining blooms to flower for a longer period of time.
Trim the dead flowers before they form seed in the inner pod of the flower head. Trimming the dead blooms at the right time prevents the dianthus from seeding spontaneously as well as supporting vigorous root development which proves advantageous when dividing the plant.
Shear the dianthus plant once it has almost completed flowering, usually six weeks after the first bloom of the season. Using garden shears cut the foliage back by up to 5 inches to retain strong shape in the bush, however, for showy evergreen foliage year round, shear no more than 3 inches. The dianthus plant will tolerate being cut back to ground level if necessary.
Harvest the seeds of dianthus after leaving the pods, housed inside the withering flower, on the plant until the pods turn brown. Snip of pods and dead blooms with shears or scissors once thoroughly dried out, at which time the seeds will easily fall when shaken. Although the plant will look unkempt and straggly for some weeks, the resulting seeds will provide a sound base for propagation in following years.