Propagating Difficult Seed

John Ward

The volunteers of the Wallum Action Group (WAG) working from the Community Nursery on Bribie Island have been experimenting on how to grow native species. I thought some of your readers would like to hear about some of the successful attempts and, of course, some of our failures.

We have tried for several years to grow Alphitonia excelsa (soap tree) using such things as Coca Cola and vinegar in an attempt to get them to germinate. This year we used a very simple method, i.e. hot water.

The seeds were cleaned and covered with cold water. Any that floated were discarded and the rest dried. Then the aril was removed from each seed and the seed placed in a container. Hot water was poured over them and they were left for 24 hours and then planted.

These seed germinated and, out of one container, we got 93 seedlings. Another batch, soaked in neat Coca Cola for 24 hours, produced only 3 seedlings.

Another species that we have tried before with very little success was Cupaniopsis anacardioides (tuckeroo). Once again, the seed was cleaned and put into cold water. All seed that floated was rejected and the remainder was left in the cold water for 24 hours. The success rate was phenomenal. We now have about 800 seedlings growing and thriving.

Another thing we have been trying this year is smoked water. The strength of this mixture was 10 ml of smoked water to 1 litre of water. We tried this on the dune love grass (Eragrostis interrupta) and Dianella sp. On the Dianella there was no difference in germination rate on seed treated and seed that was just planted with no treatment at all.

The dune love grass was a different story. The method used was as follows: The seed was put into containers and lightly covered with sand and peat, and then the containers were soaked with the smoked water. They were then covered with plastic so that the smoked water was not washed off, and left for 3 days. The plastic was then removed and smoked water applied again. It was then covered again and, after a further 3 days, it was introduced to the automatic watering system of the shade house. It thrived and we had a blanket of green emerge. This was then transplanted into tubes and we grew almost 5,000 plants which were used on the site where a movie was made, to help repair some of the damage done by the film makers.

Our aim is to use as fresh a seed as possible, but we have also had success with seed that has been stored in a freezer for 2 years. The two species which we tried were Eucalyptus robusta and Dodonaea triquetra. To our surprise both species germinated well and we will have to try these seed again, just to make sure that our first experiment was not just a fluke.

Another species that responds to cold water soaking is Lomandra. This was soaked in cold water and left for 24 hours. When we checked it, it had fermented. Rather than throw the seed away we planted it and the germination rate was really good.

It just shows that when things go wrong at times, put them in and maybe you will have success like we have.

From the newsletter of the Society for Growing Australian Plants (Queensland Region), March 2003.

Australian Plants online - 2009
Australian Native Plants Society (Australia)