Wrightia are popular as bonsai in Malaysia. When I visited Malaysia, it rained twice a day, every day, heavy rain for about an hour, sometimes more. It rained lightly off and on at night, along with heavy wet fog. The morning sun would dry things out, by 10 am things are quite dry, sunny beach weather. Then a brief storm, dry again by noon. Then around 3 in the afternoon another heavy downpour, this one lasting longer than the morning shower. Sun back out by 5 pm, by sundown clear skies, but then the heavy fog would roll in. Fog so dense that walking outside even on a sidewalk can be difficult, because you might not even be able to see your feet. The fog would get everthing dripping wet. The ground never dried out. This was in the Genting Highlands. In the cities the fog is not as bad, but the daily rains are the same. Everywhere along the streets Wightia is planted as a landscape plant. You can smell the flowers everywhere you walk in residential areas where they have landscaping. They love wrightia both as bonsai and as a landscape shrub.
There is a reason wrightia is called "Water Jasmine". I saw many a potted plant of wrightia standing in a tray of water. They never want to get dry, and tolerate standing water almost as well as bald cypress. Well, maybe not completely submerged like bald cypress, but they do well standing in a tray of water for the summer.
The other is they come from tropical areas. Standing them in water works well when temperatures are above 70 F, or 20 C. When it is cool, below 70 F, they probably should not be standing in water. They really only grow well when termperatures are warm, much like Ficus, so when temps are warm, keep them in shallow trays of water. In winter grow them more like conventional bonsai.
Standing a bonsai in shallow trays of water to keep them wet is actually a common practice in summer. It can be done for Wisteria, Wrightia, Bald Cypress, Metasequoia, Willows. These species will tolerate, even appreciate being in shallow standing water continuously for the warmest months of the summer, bald cypress can be kept constantly submerged.
If you find yourself having to water a tree two or more times a day, a good practice would be to put it in a shallow tray of water. Fill the tray in the morning when you water. Then at night, if it is not empty, empty it for the overnight. Refill the tray again when you water in the morning. This method will work for species that are not normally grown in standing water. Hornbeams and maples in shallow pots can be helped through the hottest part of the summer this way.
