Q.What Is The Maximum Heat Temperature For Oleanders?
The local high temperatures for the last several days have been over 100 …102,103,104,105 106 and a scorching 107 yesterday. I blocked the sun using cardboard squares on wood stakes when the temperature is highest during mid to late afternoon
Mine in Texas have been exposed to temps as high as 117F in previous years so I water & mulch them deeply during those hard times. Water deeply like you wood a shade tree but not often. Test the mulched soil first. Maybe 1-2 a week depending on heat and local rains? As they do not get enough water, they drop leaves and the canopy opens up. So it probably depends on other factors such as the cultivar, drying winds, fertilizer (do not fertilize when hot or very hot), mulch, soil type, available afternoon/evening shade from other trees/structures/building, etc. Test the soil and do not water if the soil feels moist or soggy... if it is going to be very hot and the soil feels soggy (or there is also a chance of windy conditions), I may water that one time.
