Hibiscus laevis, commonly called smooth rose mallow or halberd-leaved rose mallow, is a Missouri native herbaceous perennial which typically occurs in wet soils along streams, rivers, ponds, sloughs, ditches and swampy areas throughout much of the State. Perhaps most easily distinguished by its three-lobed leaves (to 6" long) which resemble the shape of the 15th-16th century halberd spear. Large, 5-petaled, hollyhock-like flowers (to 6" diameter) with white to pink petals and maroon eyes appear from mid-summer into fall on smooth stout stems rising 4-6' tall. Each flower has a prominent and showy center staminal column. Synonymous with and formerly known as Hibiscus militaris, the specific epithet being in reference to the leaf-shape resemblance to a military weapon. (info source: missouribotanicalgarden.org)
Genus - Hibiscus
Species - Laevis
Common name - Rose Mallow
Pre-Treatment - Not-required
Hardiness zones - 4 - 9
Height - 4'-5' / 1,20m - 1,7m
Spread - 2'-4' / 0.6m - 1.2m
Plant type - Shruby flower
Vegetation type - Deciduous
Exposure - Full sun
Growth rate - Fast
Soil PH - Acidic, Neutral
Soil type - Rich soils, Clay, loam, well drained
Water requirements - Average, moist
Landscape uses - A tall mallow for moist soils along bodies of water or in low spots. Also effective in border rears, cottage gardens or native plant gardens.
Germination rate - 86%
Bloom season - August to September
Leaf / Flower color - Green, Dark Green / White to pink
|Seeds can be planted in a commercial seed starting medium or a mix can be made out of some combination of sand, perlite, vermiculite. The seeds are planted 1/4 to 1/2" deep in the mixture and should germinate in a week to a month on average.
It is best to keep the temperature about 80 to 85° F (about 28° C) and the medium moist, but not soggy. A heat mat to provide bottom heat is helpful.
Until you have found out what works best for you, the seed starting kits that are available in gardening stores and catalogs that use small plastic cells may be the best way to start -- one seed per cell.. Some have used styrofoam coffee cups with drainage holes poked in the bottoms and 100% perlite to start their seedlings. Some plant several seeds in 4" pots. Putting the pots/cups, etc. in trays with clear domes and starting under lights can give them a headstart.
It is absolutely essential that you do not use too much water. Seeds will rot and will not germinate if they stay in a wet/soggy medium.
After the seedlings have developed several sets of true leaves and the stems have begun to harden and become woody, they may be moved to a larger pot. A water soluble 20-20-20 fertilizer can be used per label directions at this point. Some growers will move these 3 or 4" tall seedlings to a gallon plastic pot containing potting soil, others will move their seedlings up in several stages to gallon pots and use soilless mixtures. Some growers plant their young seedlings in the ground in their own bed. (Always avoid disrupting the plant and its roots as much as possible in these moves.) These small seedlings should be gradually introduced to sun over several days. Remember they are tender, so avoid temperatures in the 40s.
Information source: trop-hibiscus.com