|The best time to hybridise hibiscus is from autumn to
early winter. The cooler weather is ideal, as high temperatures dry out or
inhibit the pollen so that it is not as viable. Pollen may be stored in
vials in the refrigerator until a wanted female parent blooms.
After the petals fall the fertilised ovary enlarges. In a few days the calyx tips should be trimmed away carefully to prevent them harbouring insects. It is important to keep insects off the pod in the early stages, for sometimes they will sting a seed capsule and cause one of the sections to die. More seeds are lost to insects than any other cause. It is a good idea to carry with you in the garden an aerosol can of insecticide to spray the pods or a puffer pack of insecticide dust. The pod will ripen in forty to ninety days, turning from apple green to light brown. At the earliest sign of cracking open, a square of nylon net may be tied around the pod to prevent loss of seed. When the pod cracks open it should be picked, the seeds counted, placed in a shallow container to dry, then transferred to an envelope or box marked with the cross number, date, and other information. In general the larger the seed, the larger the flowers will be.
Some hybridisers plant the seed immediately, others let is dry for several days or even several months. Sometimes it is a good idea to wait until spring before sowing the seeds, so the seedlings have a full growing season before them before the winter comes, unless of course you have glasshouse conditions available. A suitable medium must be mixed in which to sow the seed. Vermiculite and peat, perlite and peat, sand and peat or compressed peat blocks are ideal. A depression 6 mm (¼ in) deep should be made in the medium to receive the seed. It is important that the planting medium be sterile to avoid diseases. In profile, the seed appears much like a human head. Hold the seed by the face to protect the embryo and then with a single edged razor blade (Gem type) or sharp utility knife, nick or scalp the rounded top of the head until a whitetop appears. This hastens germination. If you have difficulty finding the top of the head, take the seed between your thumb and finger and roll it a couple of times and it will stop in the right position. Because it is tapered on the bottom it will stop with the narrowest part down and you can nick the top of the head. Drop the seed in the depression you have made, cover it with sterile sand, and moisten thoroughly. When properly nicked and planted seeds will germinate in six to thirty days.
After the first four leaves appear, the seedlings should
be potted, and if peat pots were used they must be covered with potting
soil. Use a sterile sandy soil. Be sure to keep baby seedlings on the dry
side if they are in a heavy soil medium. Pots for young seedlings should
be sterile. Once established, seedlings may be planted directly into
Most seedlings will bloom in ten to fourteen months, some may take longer. Do not cut back as this will delay the flowering. Retain only the best seedlings, those with promise. Discard those which are undesirable, to help minimise the proliferation of undesirable seedlings. It is worthwhile to observe the plants for a year or two after they have begun to bloom before releasing them or registering them with the Hibiscus Society. In your breeding program, use only prolific bloomers with fully overlapped petals, and a heavy to medium textured flower. This should ensure that at least you will have quality. To be a really worthwhile seedling it must have acceptable qualities that are better than any other variety in its colour range. Out of twenty seeds from the same pod each will differ in colour or colour tones, colour of eye zone and petal formation. Don't be seduced by the loveliness of a new seedling which is not up to standard; discard it! Space in a garden is valuable and a bad plant takes up as much room as a good one.
If you are sincerely interested in raising new varieties
of hibiscus from seed, then why not join a hibiscus society. The American
and Australian Hibiscus Societies have what is known as a `seed bank' and
members of these societies who are hybridising and have more seeds than
they care to plant, send them to the seed bank officer of each society
with the following information: parent identity mother first then father
then date of cross. These seeds are then available to members of the
societies. This of course is only one of the benefits one gains from a
society. The latest up-to-date cultural hints and happenings in the world
of hibiscus are available to members through periodic journals.
Do not confuse the shoots or branches of understock or rootstock which arise from below the graft on grafted plants with sports. The foliage of rootstock is usually quite different from the top portion of the plant. If any of these branches appear from below the graft cut them off immediately as close as you can to the main trunk of the plant.
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