The Lignum Vitae, also known as Gaïac, is a beautiful tree native to the Caribbean that is now endangered due to overharvesting, primarily for its extremely hard wood. This slow-growing tree has beautiful blue flowers and intricately-packed branches in its wide crown. It is sometimes described as a small tree, but this may be primarily because so few old, large trees are left.
In order to promote this wonderful heritage tree, I have been experimenting in order to develop best practices for germinating seeds, growing seedlings and transplanting them into permanent locations. Here are some images and notes about the germination process.
Small, orange fruits contain two seeds each. The seeds themselves are covered in a red, fleshy coating called a sarcotesta.
I started by separating seeds by the presumed age, based on how much of the sarcotesta remained.
I attempted germination by keeping them in damp paper towels.
After a week or so, the seeds retaining a sarcotesta began to mold and none germinated, even after several weeks.
Seeds without a sarcotesta (because it had worn off before I collected them, or because I had removed it) did not mold, but they didn’t germinate, either.
It turns out, the key is to remove the black casing around the seed. This time-consuming, but not too difficult to do with a pocketknife. To make the process easier, it seems that exposing the radicle, the embryonic first root, is all that is necessary, so one can scrape off just the casing around the rounder end.
Prepared this way, the seeds germinate surprisingly quickly, usually in just a couple days. So far, the best process I have found is to soak the seeds in water for a day or so: this helps remove any fleshy sarcotesta so the seeds won’t mold. It may also help kickstart the germination process. Once the seeds are clean, I scrape the round end to expose the radicle and leave them in moist paper towels in a warm room. So far, the majority of seeds prepared this way seem to be germinating.
(I got some very useful info from this 1966 article: Seed Germination and Seedling Growth of Guaiacum sanctum)
I have been watching birds consuming the seeds because of the red color of the inner fruit when it is ripe and exposed. Could the birds digestive tract actually digest the tough seed coat, and, eliminating the seed with its fecal matter would allow for germination, just as you scraped off the outer seed coat?
Hi Jerry! I haven’t come across confirmation of this in research so far, but it definitely seems like a strong possibility. Birds would presumably also transport the seeds away from the shade of the parent tree’s dense canopy.
I know this article is a bit old, but I’m embarking on a little Lignum Vitae growing experiment and was wondering if you found it easier to soak the seeds before scraping off the protective coating or if its better to scrape first? I have limited seeds and want to do my best to make sure I get at least one successful germination that can ultimately make it to planting in the ground and grow to a mature tree.
I have been searching on the internet, I think this is the best method. I used the grinding wheel to do the job, a lot faster than using a knife. Thank you for sharing
Sorry for the late reply, but soak first and then you can scrape off the coating with a thumbnail.
Here is the updated link cited above: https://journals.flvc.org/fshs/article/view/100471
Thanks! I updated the link.
Luckily, we don’t have that problem over here. Guayacan Oficinales grows abundently here in Curaçao, the caribbean. The trees flower multiple times a year and each time they do, they shed hundreds of seeds. Everywhere small seedlings pop up, especially after a good rainshower. Underneath one tree in my garden I found a whole forrest of seedlings. The easiest way is to dig up a seedling and plant it in a pot. You must be quick though, because it’s pen root grows down incredibly fast. I also filled a container with potting soil last year and scattered a handfull of seeds in it. After a while, one after another they kept coming…i must have had at least 15 seedlings ready to grow. I selected a few and from november 2018 to august 2019 they grew to 60-65 cm.
Btw, this article :https://journals.flvc.org/fshs/article/view/100471
is about Guayacan Sanctum, which is not the same as Guayacan Oficinales. Verawood (Bulnesia Arborea) is also called Lignum Vitae, but only Guayacan Oficinales is called TRUE Lignum Vitae and it is the tree shown in the picture on the top of this page.
”Could the birds digestive tract actually digest the tough seed coat, and, eliminating the seed with its fecal matter would allow for germination, just as you scraped off the outer seed coat?”
Well, according to this book https://natuurwijzer.naturalis.nl/media/459 from 1954 by Frater Arnoldo, who did a study about this, the germination rate seems to be significantly higher after having passed trough a birds digestive system. It are mainly the chuchibi’s (tropical mockingbird – mimus gilvus) and troepiaals (Icterus Icterus) which do this and are responsable for spreading the seeds away from the parent tree
I harvested seeds from lignum vitae in south florida. 12 seeds grew into small plants. I used your recommended method at least half of the original seeds germinated in several days. The problem was I planted them individually in jiffy mix seed growing medium. This caused most of the newly germinated seeds to rot out soon after they came up. I think it is better to plant them in well drained soil.
So, I’ve been trying to germinate using this method, but I keep having a high instance of mold even without the aril
I have also had success with just cleaning them and keeping them in a damp container. I use a jar and shake it up with some water and then drain every day or two to avoid mold. I usually get some germination within a week, peaking at about two weeks.