How to Propagate Phlox

How to Propagate Phlox

Ask an experienced gardener how to propagate phlox, and s/he will say to divide an established clump. However, there are other methods: root cuttings, stem cuttings, seed. Division or cuttings will yield new plants identical to the parent plant; seeds often do not breed true due to hybridization. Late spring or early summer is the best time to do division or cuttings.

Dividing Phlox

To divide, dig up and separate 2/3 of an established clump. Divide into two or three smaller clumps and plant each in a location with full sun or partial shade, and rich, humusy, moist but well-drained soil. Established clumps should be divided every 2 to 4 years.

Root Cuttings

To take root cuttings, dig up the edge of an established clump to expose the fleshy roots. Make 2-to-4-inch-long cuttings with a sharp knife; be sure to keep them oriented properly. The end nearest the parent plant must be upward or the cutting won’t root. Plant them in a container filled with equal amounts of sterile potting soil and peat moss that has been well-watered and allowed to drain. Space the cuttings about 2″ apart, making sure they are oriented correctly.

Stem Cuttings

Stem cuttings should be 3 to 6 inches long and include from 2 to 6 leaf nodes. Cut the stem with a sharp knife at a 45º angle just below a leaf node. Remove flowers, buds and lower leaves. Plant the cuttings in a rooting medium of equal parts coarse garden sand and vermiculite or perlite that has been well-watered and allowed to drain. Place cuttings upright in the medium with the lowest leaf node just above the surface.

Humid Environment

All cuttings need a humid environment and should be kept moist, but don’t over-water them. Once your new plants are established they can be transplanted outdoors.

Growing from Seed

To grow from seed, start the seeds indoors in pots about 8 weeks before the last frost. When danger of frost is past, transplant seedlings to the garden.