Hibiscus: Hibiscus martianus, 0 by Michael_Ronayne

Michael_Ronayne wrote:
On Saturday July 16, 2011, the tender age of seven months, my first and only Hibiscus martianus rewarded seven months of effort by producing two flowers which are 2 inches in diameter. The Hibiscus martianus is in a pot which can be brought in for the winter and stands 18 inches tall as of mid July.

A DG member from Austin TX, kindly sent me a large number of Hibiscus martianus seeds in early December 2010. Using seed nicking and the Deno Method two seeds in the first test batch of 10 seeds germinated. After that first success, I was unable to germinate any Hibiscus martianus seeds no matter what I did. The seeds appeared to be non-viable and were quickly consumed by fungus. I have read that it is better to work with fresh, newly harvested seeds of this species and intend to put that advice to the test if I am able to obtain mature seeds from my Hibiscus.

Of the two seedlings which were produced, the one which germinated in 2 days failed. The second seedling, which took two weeks to germinate, survived and flowered for the first time on Saturday July 16, 2011 at the age of 7 months. This Hibiscus continues to grow vigorously and more flowers are on the way.

I photographed the Hibiscus martianus in the early afternoon and then hand pollinated both flowers using a disposable Qtip to encourage maximum seed production. In the early morning the five stigmas are upright encouraging external pollination. By the afternoon the five stigmas bend downward to make contact with the anthers to insure self-pollination as a last resort. I have observed the same pollination strategy in another Texas native, Hibiscus coccineus, suggesting that native pollinators may be in short supply, with sufficient frequency, to make this a useful survival strategy. This self-pollination strategy is not found in other North American Hibiscus species which depend of external pollinators. By the late afternoon, the two Hibiscus martianus flowers neatly folded close, completing that phase of the plant’s life cycle.

Once the petals are shed on the pollinated flower, the sepals close about the developing seed pot and it is almost impossible to tell if the sepals are guarding a flower bud or a seed pod without peeking. In the North American hardy Hibiscus species, the sepals only guard the flower bud and remain open after pollination. I have notices similar behavior in other hot climate Hibiscus, suggesting that the sepals are protecting the developing seed pods is such environments.

If my Hibiscus martianus makes it through this summer, I intend to bring it in the house for the winter. Even I am not foolish enough to think or hope that this Hibiscus can survive through a northern New Jersey winter.

There is some confusion as the scientific name for this Hibiscus species. While most authorities identify it as Hibiscus martianus, some continue to identify is as Hibiscus cardiophyllus. If you want to do any research on this Hibiscus you must conduct searches using both names. The popular name remains the Heartleaf Rosemallow.

PlantFiles: Heartleaf Rosemallow
Hibiscus martianus
http://davesgarden.com/guides/pf/go/80842/

Hibiscus martianus is a member of Hibiscus section Bombicella. For all the species in this section for which chromosome numbers have been determined the count is 2n=22. Additional information on this section can be found here:

Hibiscus section Bombicella
http://www.malvaceae.info/Genera/Hibiscus/Bombicella.php
Hibiscus (section Bombicella) Gallery
http://www.malvaceae.info/Genera/Hibiscus/galleryB.html

There is an excellent USDA paper on Hibiscus section Bombicella. Note that you will need to down load the PDF using Firefox.

A revision of the American species of Hibiscus section Bombicella (Malvaceae), by Paul A. Fryxell, 1980
http://naldr.nal.usda.gov/NALWeb/Agricola_Link.asp?Accession...
http://naldr.nal.usda.gov/Exe/ZyNET.exe/tb16240001.PDF

Mike