I have had numerous people approach me wanting to grow their own kurrajong trees and I'm not what you'd call a "greenie" by a long shot, but I did grow up in rural N.S.W. and learned the value of these magnificent trees. Not are they only good for shade, but over the years have saved our livestock from starvation in times of drought. They are a hardy tree and can regenerate reasonably quickly. I have given much consideration to this fact and I believe these could be a part of a drought proofing strategy. A long term strategy, but rome wasn't built in a day, and all good plans are never short sighted!
I realise that this can be a time consuming process, but for those that want to "have a go", here's how I do it, and for everyone else, feel free to place an order with me.
STEP 1: Collecting the seed pods
Find a nice healthy looking tree laden with seedpods, you will know if the tree doesn't appear healthy. It doesn't matter the age or size of the tree but younger or smaller trees are easier to reach the pods without a ladder. Always be careful if using a ladder, make sure its stable and if possible tied off to the tree. REMEMBER - Safety First!
I try to collect from the ground, generally after a wind storm is the best time, a leaf rake is ideal to rake them into a pile, but collecting them off the tree is just as good. It doesn't matter if the pods are open or closed, open are good if you are ready to harvest the seed from the pod, closed you have to wait until the pod opens to access the seed.
A bunch of seed pods still gowing on the tree - they may contain viable seed however I choose to wait until they have fully developed before harvesting the seed.
Open seed pods - ready to harvest the seeds even though still attached to the tree.
STEP 2: Harvesting the seed
I recommend the first this you do at this point is reach for a pair of gloves. Inside the seed pods are really fine hairs, although they won't hurt you, they will make you itch! I use disposable food grade gloves from the local supermarket, although not as durable as gardening glose, I find them better to use as you can feel better as you collect the seeds. It is personal preference.
Once you are gloved up, select a nice pod that is starting to open, gently pry it further open until fully opened, the pod will generally break opposite the opening allowing you to "butterfly" the pod. You will see the seeds arranged in the pod and all those nasty little hairs.
At this point I take a small screw driver and gently scrape the seeds into a bowl. The next bit is where it becomes fiddly (and where I learned the importance of thin gloves!). Pick up one of the seeds and roll it between your fingertips. This will break apart the hairy seed coating and allow it to fall away from the seed, which will either be black or yellow. I haven't found much difference between the seed colours, the yellow seeds seem to be newer but both germinate at roughly the same rate. Place the clean seed into another bowl and repeat the process until you have the desired number of seeds you wish to plant. Keep in mind that the average strike rate for Kurrajongs is 40% to 60% so you will need to plant more seeds than you need trees.
Kurrajong seed collected and cleaned
STEP 3: Seed Preparation
Like many natives, Kurrajongs need heat to activate the seed, During my research I found many reputable sources all saying this. I have never questioned this just followed the "experts" and have done alright so far! I'm Not saying if you just throw them "in" they won't grow but I believe they have a better chance with heat, my research indicates that heat "awakens" the embryo within the seed.
I place the desired quantity of seed in a drinking glass or coffee mug. I boil the jug and fill the glass/mug to 3/4 full and leave it sit for 24 hours allowing the seeds to absorb moisture.
STEP 4: Planting The Seeds
I originally chose 50mm pots for planting the seeds, simply because of the number I planned to grow, larger pots were impractical for space reasons. I started planting the seeds 4 in a pot.... Big Mistake!! I soon discovered that this produced multiple plants in some pots. This required me to repot all the pots with multiples. a) this was time consuming. b) repotting increased the risk of damage / plant mortality. Hence, I soon discovered it is best to plant 1 seed per pot. This change worked well, I am always thinking about processes and how to improve them.
The next step in development was the pots, both cost and availability. I came across the idea of using disposable drinking cups, they were cheap to buy but they didn't have drain holes. Enter the soldering iron and presto! Instant pot. I took this one step further, the cups come in clear and opaque. I chose the clear so I could see the growth of the plant.
I start by 3/4 filling the cup with a quality seed raising mix. I use Osmacote as it seems to work nicely and is readily available. Next I place one seed at the side of the cup. This allows me to see when the seed germinates. You may wish to mark the cup at the point where you placed the seed to allow you to easily locate the seed to check progress. Next I cover the seed with about 10mm of seed raising mix. Next I place the cups into trays that hold water so they have sufficient water to germinate. Here Is where the waiting begins!!
STEP 5: Seed Germination
There is no hard and fast rule on how long it will take the seed to germinate. I have had seed germinate within a week but the average I have found is 4-6 weeks. Some as late as 3 months.
At about the 8 week mark, any that have not germinated, I replant. This does lead to a few multiple germinations, but a few I can live with.