Last week's ''Green Fingers'' was about trees that you can plant as a steady source of food. Cassia siamea or Senna siamea (khilek in Thai) and Azadirachta indica var siamensis (sadao) are wonderful to eat once you acquire a taste for bitter food. More importantly, they have been found to contain antioxidant flavonoids that prevent disease and lower the risk of colorectal cancer and diabetes.
Clockwise from top left, a stand of ‘khilek’ trees—pruning can make the edible parts more accessible; plumeria flowers are edible; ‘Morinda citrifolia’ shares a container with kitchen herbs; the fruit and young leaves of marum, whose powdered leaves have health benefits.
Both trees grow big over time, but they can be made smaller by cutting off the tip when they are about chest high and by regular pruning. When pruning a tree, make sure to cut just above a bud or a healthy side branch. Don't cut between two buds, leaving a stub, as the stub above the cut will wither and die and can serve as a breeding ground for organisms that can cause disease and damage the tree.
By now you are probably well acquainted with Moringa oleifera (drumstick tree, horseradish tree, or marum in Thai), whose many health benefits I have written about. It is not a shade tree but it does not require much space, and it is yet another tree which you can plant in your backyard as a steady source of food. Its tender leaves can be stir-fried, cooked in soups or parboiled and eaten with nam phrik, and its fruit tastes great in kaeng som.
In some parts of the developing world the leaves of marum are dried, made into powder and used as a nutritious food supplement for malnourished children, pregnant and lactating women, elderly people and people suffering from HIV/Aids, as it strengthens the immune system. Gramme for gramme, dried moringa leaf powder has been found to contain about 10 times the vitamin A of carrots; half the vitamin C of oranges; 17 times the calcium and nine times the protein of milk; 15 times the potassium of bananas; and 25 times the iron of spinach. All this for free if you plant a tree, which can be grown easily from seed or a branch.
If you cannot find a seed or have no friend who can give you a branch, potted tree saplings are available at Chatuchak plant market on Wednesdays. Growing up to four metres a year, a marum tree can reach a height of 15m and can live for about 20 years. Prune it regularly to encourage branching and leaf production, and to ensure that the fruit will be within your reach. You can either cut the entire tree back to a height of two metres, or cut back the branches by half.
One tree that does not need regular pruning is Morinda citrifolia (yo), which was also mentioned in last week's column. It is a small, compact tree growing to about three metres high, and you can even plant it in a big container. The tree's roots, however, cannot forage for food or moisture if it is in a container, so make sure to water it when the soil is dry to the touch and that it gets the necessary nutrients by augmenting the soil with well decomposed animal manure every year or a handful of complete fertiliser every three to six months.
Talking of small trees, John Oles wrote from Udon Thani to suggest Garcinia schomburgkiana, known in Thai as madan, as a tree to grow in a small yard. ''We have one that is about 12 years old. Although we have over 30 varieties of trees in our yard, the madan is one of my favourites,'' he wrote. ''It is green and full of leaves all year long. The fruits can be used to flavour som tam or tom yam. The shade provided by the tree is complete and cooling in the summer months. Finally, although a mature tree, it's not very tall at all.''
One dish which is not complete without madan is water lily (Nyphaea lotus, or bua sai) stalk cooked in coconut milk with steamed mackerel or pla too. Tamarind is sometimes used to lend it a sour taste but the sourness of the madan fruit is just perfect for this dish.
We had a madan tree on our farm but it was planted in the wrong place so the caretaker cut it down before I could see how big it could grow. I remember it as a beautiful tree with glossy leaves that were reddish when young. If you are going to plant madan, remember that it needs full sun like all the trees mentioned above.
Not many people think of the plumeria as food but a riverside resort known for its delicious Thai cuisine occasionally features plumeria flowers on its menu. Freshly gathered from the resort's gardens, the flowers are dipped in flour and then deep-fried. However, I wouldn't fault you if, like me, you would rather admire the flowers on the tree than on your plate.
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