El Niño, a climate pattern characterized by high temperatures and below-average rainfall, is affecting Southern Africa from November to April, leading to water scarcity and significantly impacting agriculture. The region, including Angola, Botswana, DRC, Malawi, Mozambique, Namibia, Zambia, and Zimbabwe, is experiencing a record mid-season dry spell of over 30 days, with the lowest rainfall in at least 40 years during late January/February. The El Niño is forecasted to continue until April 2024, classified as strong but milder than the 2015 El Niño. Central and southern regions have endured drier, hotter weather since late 2023, expected to persist into early 2024.
Here are some ideas to care for your bonsai during the high heat:
- Adjust your trees' positioning and watering to reduce the risk of water loss and transpiration.
- Dress the surface of your soil to reduce evaporation.
- Use Sphagnum Moss or small particle Akadama for larger collections, and wet towels for smaller collections.
- Check the soil regularly, and water as necessary.
- Consider setting up a misting system on an automatic timer to cool the air and create humidity around your trees.
Other things you can do to help:
- Cool down your benches periodically by hosing them down, especially if they are made of wood. This will create some humidity around your trees.
- Move trees away from radiant heat sources such as brick walls, metal fencing, steel shed walls, concrete, and glass, which can increase transpiration or even cook your trees.
- Make sure your tree is fed well with potassium to help it deal with stressors such as heat, frost, pests, and disease.
- Identify which trees can handle the heat and which ones can't. Deciduous trees with thin leaves are more vulnerable to transpiration, while conifers and evergreens have thicker, waxier leaves and don't transpire as quickly.
- Reduce leaf mass if you have trees with a dense canopy. The more foliage a tree has, the more surface area it has for water loss through transpiration.
- Stay on top of pests with preventative sprays. Pests attacking your tree will weaken it and reduce its tolerance to extreme conditions.