Plant Answers

Hibiscus Propagation

1. Tropical or Chinese Hibiscus (Hibiscus rosa-sinensis).

These plants are best propagated from softwood cuttings taken in May, June or July. Softwood cuttings are the soft, succulent, new growth just as it begins to harden or mature. Shoots are suitable for making softwood cuttings when they can be snapped easily when bent and when the newest leaves are still smaller than the mature leaves. They can also be propagated from semi-hardwood cuttings taken from mid July to early fall. At this time the wood is reasonably firm and the leaves are all of mature size.

Cuttings should be about 3/8 inch in diameter and 6 to 12 inches long. Remove all but the top two or three leaves. Dip the bottom of the cutting in rooting hormone such as Rootone and insert the cutting in a moist but not saturated rooting media of good potting mix or one of one half sphagnum peat and one half coarse washed sand.

Since the cuttings will root best if kept in a humid environment, it is best to use a system such as that described in the article Plant Propagation by Stem Cuttings: Instructions for the Home Gardener found at http://www.ces.ncsu.edu/depts/hort/hil/hil-8702.html . This is what it says: “A greenhouse is not necessary for successful propagation by stem cuttings; however, maintaining high humidity around the cutting is critical. If rooting only a few cuttings, you can use a flower pot or other container. Maintain high humidity by covering the pot with a bottomless milk jug or by placing the pot into a clear plastic bag. Cuttings can also be placed in plastic trays covered with clear plastic stretched over a wire frame. Trays must have holes in the bottoms for drainage. The plastic will help keep the humidity high and reduce water loss from the cuttings.”

The container with the cuttings should be placed in a well lighted location out of direct sunlight. The rooting media should be kept slightly moist. Rooting should occur within 3 to 5 weeks. When the cuttings have successfully rooted, the top of the stem should be cut or pinched just above a leaf node. This will encourage a bushier plant.

Some start softwood cuttings in water by just placing them in a container with about 2 inches of water in which a few drops of hydrogen peroxide has been added which is placed in bright light but not direct sunlight. This water should be changed about once a week. After about a week, calluses will appear and about a month later roots should appear. After the roots have changed from white to a light tan color, you can transplant them into containers or directly into the ground.

2. Perennial Hibiscus (Hibiscus moscheutos or Hibiscus mutabilis)

Cuttings of these hibiscus can be rooted at anytime that new growth is available but it is usually quickest and most successful in the spring. Use pencil thick cuttings of firm new growth that are about six inches long. Strip off the lower leaves, leaving only 2 to 3 leaves on top. Dip the cuttings in rooting hormone and stick in containers of a rooting media of a good potting mix or one half sphagnum peat and one half coarse washed sand. Provide a humid environment such as that described above. Roots should form in about a month.

Perennial Hibiscus can also be propagated by division in the spring. Be careful working around the soft new shoots. They usually do not tolerate division in the fall.