Caring for Your Bonsai on Hot Days in New Zealand

In New Zealand, the summer sun can be quite strong, with days of intense heat that differ from the more temperate climate of Japan. As a bonsai artist, I have come to understand the importance of adjusting our care for the unique conditions our trees face. On hot days, the challenge lies in ensuring that your bonsai remains healthy and protected, while still allowing it to enjoy the warmth of the sun in moderation.

Here are some tips to help your bonsai thrive on the warmer days:

1. Protecting your bonsai from from excessive sun

While bonsai trees naturally enjoy sunlight, the intense heat of the New Zealand summer can sometimes be too much for them, especially delicate species. I recommend placing your bonsai in a spot where it receives partial shade during the hottest part of the day, usually from late morning to early afternoon. A light, filtered shade helps the tree continue to absorb sunlight without the stress of direct heat.

2. Water with care

On hot days, the bonsai’s water needs may increase, but it is essential not to overdo it. I usually water in the early morning or late evening when temperatures are lower. Be sure to check the soil before watering; it should feel slightly dry to the touch but not completely parched. Water deeply but gently, allowing the roots to absorb the moisture without becoming waterlogged.

3. Potect bonsai from wind exposure

Strong winds combined with heat can dry out the soil quickly, leading to stress for the tree. Try to position your bonsai in an area that is shielded from both the harsh sun and strong winds. A calm, sheltered corner or beneath a tree's canopy can provide a more stable environment for your bonsai to endure the hot days.

4. Humidity and air circulation

Bonsai trees, like all living things, benefit from good air circulation. During hot spells, it is especially important to avoid the air becoming too stagnant. I sometimes place a shallow tray filled with pebbles and water near my bonsai to help raise the humidity around the tree. This provides a more comfortable environment without excess moisture directly on the roots.

5. Prune and style carefully

While it may be tempting to prune and shape your bonsai during the summer months, it is best to wait for a cooler period. On hot days, trees are often stressed, and heavy pruning can weaken them further. If you must prune, do so lightly, removing only dead or unhealthy growth. I believe it is always best to respect the tree’s energy, allowing it to focus on maintaining health rather than encouraging new growth during the heat.

6. Use shade cloth when needed

For bonsai species that are particularly sensitive to the heat, shade cloth can be a great aid. This simple covering can protect your bonsai from the full intensity of the sun while still allowing it to breathe. If you find that your bonsai is struggling, a shade cloth will offer gentle protection without completely blocking the sunlight it needs.

7. Avoiding excess fertilising

During the heat of summer, your bonsai is already under some strain, so I prefer to refrain from heavy fertilizing until the cooler months arrive. A light, slow-release fertilizer can be used sparingly, but it is better to allow your bonsai to rest and conserve its energy during the hot days.

These tips, though simple, are meant to help you maintain your bonsai’s health and well-being during New Zealand’s hot days. Every tree is unique, and by observing it carefully, you will learn the best way to provide the care it needs. I am always reminded that in bonsai, as in life, patience and gentle attention are the key to flourishing.