Northamptonshire Bonsai Society

Summer Care For Your Bonsai

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In early summer any trees that remain under shelter in greenhouses or polytunnels, such as those that have been repotted or otherwise of a delicate nature can be brought out into the sun. It’s always worth remembering that most bonsai, considering they are grown in pots, will benefit from the provision of some shelter for part of the day when the sun is at its hottest.

As summer advances your trees will be more demanding of watering frequency. The majority of bonsai deaths happen purely because the tree ran short of water. Whilst over watering has the potential to kill a tree eventually, under-watering is almost guaranteed to kill a tree. Ensure regular watering throughout this season. Once a day should be minimum, but with increased temperatures, up to 2 to 3 times a day may be required. Automatic watering systems can be a big help in maintaining a watering regime, but it’s as well to remember that these can fail, and they will only ever fail when they are in use! If you do use automatic watering systems keep a check on them to ensure they are performing as you expect.

This is a prime time of year for bonsai growth, and the same can be said for pest and diseases. It’s a good idea to give your trees a quick check over when you make your watering rounds. Just check on the condition of the foliage, and lift one or two leaves to look for aphids or scale insect. If you do find a problem act quickly to avoid it becoming a larger issue for the tree and prevent it from spreading to other nearby bonsai.

Whilst this will be a busy time of year for much pruning and pinching, it’s worth remembering that allowing a tree to grow before doing any such work on it will always be of benefit to the tree. Allowing growth extension, whilst keeping an eye on a balanced development of the tree, will generate energy in the tree that can later be used to produce increased bud production. As the trees grow more rapidly in summer, check for any training wire that remains to ensure it doesn’t bite in and cause damage to the bark. This may not be quite so important on conifer species, but fast growing trees with delicate bark suck as Maples and Beech can be damaged and this damage may never disappear as it would do on say a pine.

 

Most deciduous trees won’t need feeding until mid summer, but conifers should be fed regularly at this time of year. If you feel more comfortable giving some nutrient to your deciduous trees, try some 0-10-10 fertiliser as a tonic. The lack of Nitrogen in this feed means you won’t be encouraging excessive green growth, but the Phosphorous and Potassium will be of benefit to the trees.