Things You'll Need
Perennial dianthus are grown for their spicy fragrance and pretty pink, red and white flowers that bloom in late spring and summer. There are countless hybrids and species. Grow perennial dianthus in full sun, in moist, well-drained soil. Some perennial dianthus self seed. If you don't like the extra plants, weed them out in the spring when they are still small. Enrich the soil with compost every fall to prevent the center of the plant from dying out. Perennial dianthus are divided in autumn, too.
Dig up the perennial dianthus plant, shake out excess soil and turn over the plant. You may see natural divisions; if so, use these as your guideline. If natural separations are not apparent, pull apart the roots with both hands, dividing the dianthus plant into pieces. Make as many divisions as you want.
Replant the pieces in other parts of the garden. Dig a shallow hole 2 inches deeper and wider than the root ball. Sprinkle 1 tbsp. of lime in the bottom of the hole. Dianthus plants thrive in alkaline soil. Place the root ball into the hole, back-fill with soil and firmly tamp down around the plant.
Water the perennial dianthus plant to help it settle into its new home. Spread a 2 inch layer of compost around the dianthus to enrich the soil and feed the plant.
Give away extra perennial dianthus divisions to friends or throw them onto the compost heap.