No matter what, when it gets hot, we risk losing plants and trees.
The problem is that the irrigation systems cannot take a hard freeze... so we walk that delicate balance of waiting until the last minute and then getting the irrigation systems in place, repairing the left-in-place tubing from damage the season before (or from chickesn or freezing over the winter), replacing timer batteries, putting the systems back together, reprogramming the timers and testing everything.
Inevitably, it is a race against the clock on these volatile spring days. Too cold, then too hot, and maybe a cold snap comes again.
The more we plant, the more difficult "irrigation weekend" has become. I have now officially reached the limit for a one person operation--I'll need to train others in irrigation or risk losing perennials.
The lesson here?
Do not expand beyond your ability to put systems in place. Really--it is that simple.