What are those funny like things hanging from my favorite plumeria? They look like a giant propeller or a banana. Wow! You are in luck that is a seed pod.
Not every Plumeria produces a seed pod. Some have them every year; some rarely or ever produce one. They will start any time during the blooming season and will stay on the plant through the winter. The pod will be a greenish-yellow or a reddish-brown. The seed pod takes 9 to 10 months to ripen.
When the seed pod starts to shrivel and a crack appears down the seam, it is almost ripe. At this time your can place a mesh bag (like you can get in the grocery store produce department) or some cheesecloth over the pod. The reason for this is to catch the seeds. If you are not there when the pod opens fully, the seeds will be scattered by the wind. You may also pick the pod if you so desire. If you watch the pod, you will see it start to split down the seam you may remove the pod from the plant at this time. Open the pod and remove the pulpy piece that runs along the split. It is similar to the strings on a banana, only it will be larger, about 1/4 to 3/8 of an inch wide. If you do not remove this, the pod will tend to mildew, and you will have lost all of your seeds.
Now you have 30-40 seeds and what to do with them? I place the pod in a paper bag to dry for about two weeks. Check on them occasionally to make sure they are drying properly. Plumeria seeds will stay viable for one to two years, but the sooner you can plant them, the better germination rate will be. The seed looks like a pine seed, with a head and winged tail. Everyone has their own way of planting seeds, and this is the way I plant mine:
I use 2 x 2 x 2 ½ inch plastic starter trays. I fill the cell about 3/4 full of perlite and dampen it. I then make a small depression in each cell and place the seed head down, and leave about half of the tail exposed. Next I fill the cells, leaving part of the tail exposed. Then saturate the planting medium, being careful not to float the seeds. Your seeds need to be kept warm about 70 degrees and damp. Your seeds should sprout in about 5 to 10 days.
When the cotyledons (green leaf-like structures) appear, the seed coat should have come off. If it has not, it must be carefully removed. I use a spray bottle to wet the seed-coat, let it sit for a few minutes and then very gently remove it, being careful not to damage the sprout.
After the first true leaves appear, I till feed them with a weak solution of Miracle Grow. When the seedling is two to three months old, I will then transplant it into a larger container of potting mix. At the time of transplanting, I use solid fertilizer tablets (Grow Power 3-12-12). I place them one to two inches below the seedling’s roots. As the roots grown down, the fertilizer will be available to them, giving them a great boost. Now all you have to do is care for the plant for the next two to three years. You may get a bloom that could be a show stopper.