France has experienced its worst inundations since 1980, and unprecedented flooding has occurred in places as far apart as Australia and California. Climate change? Of course. Deforestation? Unnaturally…
Just to take one local example. On Aug 23, 209 properties were damaged and 13 people lost their lives as a likely consequence of a massive landslide near the Big Buddha in Phuket. Why? Because several rai of land at the summit of Nakkerd Hills had been cleared of trees to make way for a car park. The natural sponge provided by tree roots had been destroyed.
The story for gardeners is less dramatic, but nonetheless impactful. As enthusiasts know full well, the needs of tropical plants vary. Xeric plants, originally from arid or desert regions, will succumb and rot if their roots sit for too long in sodden soil. Plants such as cacti, and other succulents – yuccas and agaves for example ‒ love Phuket’s sun, but detest the drenching rain. Their best chance of survival is in sandy or gravelly soil that drains quickly, or in raised beds, containers or rockeries. High levels of humidity don’t help. A reader recently wrote about the difficulty of cultivating lavender (lavandula) here. I have experienced the same issue. In my garden in rocky terrain in mountainous southern Spain it grew like a weed, thriving in conditions of dry soil and low humidity. It is a Mediterranean plant.
The southwest monsoon affects your garden in other ways. The growth of fungi and other microscopic life is encouraged by surfaces that are frequently warm and moist. All my sand-washed surfaces (sai lang) around the pool and on the balconies have become discoloured. Light-coloured paintwork takes on a grey hue. After 16 years, I have had to replace the wooden window frames on the windward side of the property as well as three rustic trellises.
Other unwelcome visitors put in an appearance, including giant millipedes and snails. In fact, the millipedes are harmless detritivores that feed on rotting vegetation, but they are poisonous. Most importantly, the soil is drenched so often that the leaching process causes it to become compacted, worse to lose most of its nutrients. But it’s an ill wind… Worms, encouraged by the presence of moisture, help to aerate the topsoil by returning to the upper layers. And if you can, add compost to your tired soil.The more organic matter, the better.
And at the other end of the spectrum are shrubs which thrive in Phuket’s protracted southwest monsoon. Some of these are flowering marsh plants such as canna lilies or bottlebrushes (callistemon), which naturally grow close to water or in boggy areas. Most ferns take on a new lease of life, even invading containers. The spectacular bird’s nest fern (asplenium nidus) puts on a growth spurt. A couple of mine are now four feet across.
In general, it is fair to say that shade-loving plants, most of which exist under the forest canopy in the wild, will flourish at this time of year – especially aglaonemas, dieffenbachias and caladiums. They are all cultivated for their large decorative leaves, a feature which allows them both to absorb efficiently what limited sunlight is around, and to breathe out excessive amounts of moisture.
I have not considered drought-loving plants. Suffice to say that most will and do survive the ordeal by water. One xeric shrub that does do well here is the adenium or desert rose. Since it hails from the tiny island of Socotra south of Yemen in the Indian Ocean, it needs little moisture. After all, in its native surroundings, rain falls in only one month of the year: November. Technically known as a drought-deciduous succulent because it drops most of its leaves in rainless conditions, the adenium has grey, swollen (pachycaul) stems which retain water during extended dry spells in the form of a latex-like fluid.
But the primary reason both for its popularity and success in Thailand is that it does well in containers. Grown almost exclusively in pots with large drainage holes, it requires little watering, and yet manages to produce richly coloured blooms in shades varying from white to a luminous red. The shrub has been widely hybridised.
Containers are, in fact, one potential solution to all these climatic excesses because the attentive gardener can thereby control the micro-environment of his plants. Water your pots in the dry season, drain in the monsoon. Watch the progress of your charges. And move them to a new location where necessary.
Patrick Campbell’s book ‘The Tropic Gardener’, described in one Bangkok review as the best book on Thai gardening for 50 years, is available for B500 (half price) to personal callers from 59/84 Soi Saiyuan 13 in Rawai (Tel: 076-613227 or 085-7827551).