Here in the Northern Hemisphere the heat of summer is full upon us, with equally oppressive humidity and poor air circulation as is typical for the Midatlantic region where I live.
Summer is a unique time in the yearly lifecycle of most bonsai; special attention must be made for almost all deciduous and coniferous species. Many trees go through a sluggish torpor at this point of the year, where their metabolism slows or even stops for several weeks as a defense mechanism against the heat. This means attention to watering is critical. Other points:
–Fertilizer should be temporarily removed from the bonsai pot, and the application of liquid fertilizers suspended until late summer/early fall. –Mountainous trees such as Spruce, Larch, and Hemlock, and understory trees such as Beech, Hornbeam, Mountain Maple, and Azalea should be placed in shade when the temperatures exceed 89° Fahrenheit. Misting the foliage while maintaining somewhat moist (but not wet) soil conditions is wise. –Now is a good time to do major carving tasks on resinous trees. –In hot, windy conditions bonsai need frequent watering, so check often! –No major work should be done on roots, and no transplanting or collecting of trees should be done this time of year unless you are very experienced doing so—aftercare is critical and trees are easily lost by transplanting out of season. –Tropical bonsai love this time of year—most thrive in sweltering heat and full sun, so make sure they have good exposure outdoors. –Bear in mind many flowering bonsai are setting buds this time of year for flowering in the coming year, so go easy with pinching and pruning of Azalea, Laurel, Rhododendron, Magnolia, etc. –Remember to rotate your bonsai on a regular basis so all sides receive equal amounts of sunlight.
So else what can you do this time of year? Check wiring, make sure it isn’t cutting into your tree’s branches. Weed. Water. Stay cool!