Answer: You can coax your diathus to bloom again later in the summer if you cut the entire plant back by two-thirds now. I just take my garden scissors and shear the tops off of my dianthus. This will stop seed production and keep the plants blooming for a longer period of time. If you want to collect seeds, don't trim them back later in the summer. Instead, allow the last flowers of the season to remain so they can develop seeds. You can either allow the seedpods to burst open and spread seed in the general area of your dianthus plants or you can collect the seed pods after they turn tan but before the open and spill their seeds. Store them in a cool dark place and plant the seeds in the spring by scattering them over the soil. I would leave the dead foliage in place over the winter months and then cut it away from the crowns of the plants in the very early spring.
Best wishes with your dianthus!
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