Tropical Permaculture Perspectives
A perennial guild -- Pak Wan Pa (Melientha suavis) and Longan (Dimocarpus longan)
Visiting Por Phat Aphaimool’s forest farm in Mae Tha, Chiang Mai, again after a long time was a chance to learn as I always do from his many years of experience and wisdom. This time the Thai farmer happily showed us how he had successfully planted the delicious long-lived perennial vegetable Pak Wan Pa (which translates as “wild sweetleaf”) amongst many of his longan trees.
This vegetable is one of the most prized amongst Thais and personally one of my favourites. In the past it was mainly wild harvested, but many within the organic/sustainable farming communities have been working to learn how to establish it in our own forest gardens. Once established, it can live for many hundreds of years.
Por Phat had planted it right next to the trunks of his longan trees. He explained that this vegetable is very deep rooting and thus does not at all compete with the longan trees. It also, as a forest species, is adapted to getting started in shade, and only shooting up to the sun once it is well established.
Here farmer Por Phat Aphaimool shows a two-year-old seedling just to the left of his post. Now with about five leaves, and growing directly under one of his longan trees.While he said he learned this method from others, he explained to us clearly the rather complicated procedure that he went through to get the sweetleaf trees established.
- Take the seeds/ fruit collected and rub them clear of pulp using a sort of rough sponge (like a Scotch Brite brand).
- These seeds then should be placed in layers of clean sand directly on the soil — about 2cm of sand per layer of seeds. The sand is kept moist. This will give space for the seeds to sprout and allow them to be removed without damaging the roots. (This is a critical point as if the initial tap root is damaged or caused to bend in its growth, the plant will not make it.)
- When the seeds have about 1cm of root they are ready for transplanting.
- We must prepare in advance the transplanting holes. This is done by digging out a tube of soil about half a metre deep and 10cm in diameter (about the size of a can). This hole is then packed with compost. Then we must use a long rather sharp and strong stick, or more often a thin bar, to make a hole from the surface through the compost and then to about one metre total depth.
- The seed is placed on top of this hole with the taproot going down into it. It should then be covered with rice husk charcoal (biochar) to prevent insect damage and be clearly marked. (Marking is critical.)
- These plants grow very slowly initially (the first two years), and then take off later.
Pak Wan Pa, with it deep super roots as Por Phat explained, is a special boon as it provides delicious abundance in the toughest part of the year, producing its copious shoots at the peak of summer from late March through April and May.
It is easy to eat, being a good addition to soups or prepared in a quick stir fry, which could include wild forest mushrooms which should also be appearing in a healthy forest garden after the first summer rains.
While you may need four years or more to start harvesting these shoots, you can also rest content that you will be passing on some real wealth to future generations that even your great-great-grandchildren should be able to enjoy.
Now, after four years, another Pak Wan Pa tree is approaching the height of the longan — and firmly established for generations of production.
It could also have been mentioned that this plant can also be propagated by cuttings. Here in my SE Qld garden I have several of these around my garden as I love to cook and eat this amazing plant.
Dear Colin, Thanks for sharing. Here in Thailand never seen Pak Wak Pa grown by cuttings, if you can share a bit about technique great. The much more common Pak Wan Baan (Sauropus androgynus), also tasty but not as big or long lived, it very easily grown from cuttings. Just to check that we are looking at the same species as Thai name is common to both, one wild and one home.
Dear Colin, Thanks for sharing about propagation by cuttings. As I have never heard of this being done here in Thailand for Pak Wan Pa (Melientha suavis), would you share a bit on the how?
Just as both species here are commonly know as Pak Wan in Thai- also want to check that it is not Sauropus androgynus that you grow with cuttings. Sauropus androgynus is commonly grown here with cuttings. Also very tasty, but not so long lived and it does not develop into such a large tree/ bush.
How can we avail of the seed of this plant for planting in the here in the Philippines?