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
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
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.