Growing Hibiscus From Seeds -- by Dick Johnson
Special thanks to Mr. Dick Johnson of Tahiti for providing the following information on grafting. To view Dick's site please go to http://www.hibiscus-of-tahiti.com/
Although the seed can be planted as is, it is highly recommended that it first be nicked or abraded to permit moisture to enter and initiate the germination process. With fresh seed it is perhaps better to wait a week or so to permit the seed coat to harden which facilitates nicking. Moreover, some believe this brief drying period permits the seed to mature, thereby providing a slight increase in the percentage of germination. If the seed is not nicked, it may not absorb enough water to commence the process of germination for many, many months, and such unnicked seed has been known to germinate as much as a year or more later. Nicked seed, on the other hand, will produce fairly rapid germination with the early risers making their appearance as soon as 5 days after planting and the majority will appear within 3 to 4 weeks. It is rare that nicked seed germinates after 2 or 3 months. Nicking is not difficult. Simply press the seed, underneath the tip of a fingernail, against a surface upon which it can be cut. With a sharp razor cutter, used in a sawing motion, remove just the smallest amount of seed coat possible so that the white of the embryonic tissue is exposed. Be sure to nick the round end, as this end is where the seedling leaves are found, and if cut too deeply will just result in their being nicked but will do no harm. If one cuts at the pointed end, where the embryonic root is located, this can be fatal. One can also use a fingernail file or sand paper to abrade the seed coat sufficiently so that moisture can enter the seed.
The planting mix is not that critical, requiring only that it does not remain soggy wet or contain fertilizer in dosages intended for potted plants. Any commercial seed raising mix should be quite adequate. If such is not readily available, there are many formulas for producing a mix adequate for germinating seed which range from just sand or vermiculite to a mixture of any of the following: sand, peat, pearlite and/or vermiculite. There are many different means of planting seed, and it is up to each person to decide upon what seems to suit their situation best. Seeds can be planted individually in small pots, cell trays, Oasis or Rockwool cubes, etc. With these methods transplanting is simple as there are no adjacent seedlings resulting in a tangle of roots. However, as hibiscus are generally tolerant of the stress of transplanting, one of the simplest means is to place the seed raising mix in a 4” pot and evenly space up to 10 seeds on the surface. Plant about 3 diameters deep by covering with about ¼” (6 mm) of mix and water gently but thoroughly. Experienced seed growers keep the media just damp but not soggy, under which circumstances there is generally little problem with fungus. However, in damp and cool conditions, fungus may attack the stem of the seedling at the soil level, causing it to topple over which is normally fatal and irreversible. This is called damping off and can be prevented by the use of a fungicide. Failing a commercial product made for this purpose, a 10% bleach solution can be used as a fungicide (1 part out of the bottle to 9 parts of water). Some prefer to apply a fungicide incorporated into the water upon sowing of the seed, which is probably a good precaution for those that are new to growing seed. However, unless growing seed on the cool and wet side, this is often unnecessary.
The seed can be germinated in anything from bright shade to full sun, and the soil should be maintained at a minimum temperature of 70 – 80 F (21 - 27 C). In colder climates, this may require a heating mat, which can be acquired from local or on line nursery suppliers or even, with a little ingenuity, built from scratch. Although seed may germinate in normal household conditions, they often do better in a humid environment. This can be accomplished by purchasing any one of a number of seed propagators, or by simply placing the seed container in a plastic sack, or covering it with a translucent plastic cup, or placing a cut off plastic soda bottle over the pot.
As the root emerges from the pointed end, when planting just a few seeds, it might be helpful to plant them with the pointed end downward. However, this is usually not necessary if the seed is planted deep enough, in which case the roots and leaves will orient them selves properly on their own. Should you see a seedling emerging root first or with too little of the root in the seed raising mix, pierce a hole in the mix with a pencil and place the seedling into it root first pressing the mix gently around the base of the seedling.
When the seeding has developed a couple of real leaves, which differs from the two initial seed leaves that provide the initial energy to get the plant started, they can be transplanted. It is best to handle the plant by the leaf rather than the stem which is easily damaged even by slight pressure. Normally seedlings are transplanted first into 4” pots, and when they have outgrown this size (usually indicated by roots come out of the drain holes) they can be shifted to 1 gallon containers which will tide them through to their first bloom.
Shortly after emergence seedlings should be fertilized with a balance fertilizer. Some feel that frequent dilute feedings with a liquid fertilizer produces the best results. Seedlings are found to develop best if grown in full sun, and the first bloom will be achieved more rapidly by simply letting the seedling grow without pruning. This permits one to cull those that are not worth keeping. Normally, a desirable seedling will then be grafted onto a variety know to have inherited a superior root system which is referred to as the root stock. This grafted seedling can be pruned to provide a properly shaped bush. Since as much as 90% of seedlings from good crosses produce pleasing blooms, albeit not perhaps as good as others that are similar and in distribution, one might wish to keep them for their own pleasure. In this case pruning the seedling will result in a more appealing bush, but will retard achieving a first bloom by anywhere from a couple to several months. The first bloom of a seedling can reportedly be accelerated by grafting it onto a good root stock at an early age or growing a 4” tip cutting taken from a seedling of about a 12” height, which surprisingly it is said will bloom sooner than the seedling itself. In tropical climates a seedling might bloom as early as 5 or 6 months from germination. More commonly the first blooms will occur between 9 and 12 months and most will bloom within 12 to 18 months. Some may bloom when only a foot or two tall, while others may not bloom until they are six to eight feet tall.
The first bloom of a seedling is not always indicative of the way it will bloom when mature. Hence, seedlings should be permitted to bloom several times before making tentative decisions, and those that are considered keepers should be evaluation for one or two years to determine their merit. Seedlings which are deemed superior, i.e., distinctive or better than similar varieties in circulation with good bloom and bush characteristics (perhaps just one or two percent) may warrant being registered. In such cases, the accepted standard in the hibiscus world is to list the person who produced the seed as hybridizer, while the person who has grown it, would be listed as the grower. Information on registration of seedlings can be acquired from the IHS, AmHS or AuHS although only the latter two actually maintain registries – that of the AuHS being the official International Registry.
Hibiscus Species Seed
Hibiscus rosa-sinensis is called the tropical hibiscus, meaning that a large percentage of other varieties are more temperate in origin. Hence, many have built in dormancy, not found in H. rosa-sinensis. This kind of seed is usually treated differently, wherein the dormancy is broken and germination initiated by a hot water soak. Partially fill a glass with maximum hot tap water, place the seed inside for 24 hours and then plant as above without nicking. Such seed can also be germinated after the soak treatment by placing between layers of damp paper towel, but should it dry out, the germinating seed may perish. Upon germination, the seed can be planted.