All new plantings will be quite susceptible to wilting in heat until they get their roots out and established deeper into the soil. This could take as long as a year in some cases, but in almost all cases the first week will require daily waterings and the next week every other day. Eventually you will get to once a week and then you can play it by eye, waiting for signs of wilting and giving them water. If I see wilting, like I did today, I give a temporary drink to perk them up and then I give them a deeper watering the next morning, this helps to avoid moisture related problems as most of our plants don't like to be too wet through the night. Some are very susceptible to this and will rot pretty quickly if repeatedly left wet at night. Pentas are pretty bulletproof though. But watering in the evenings usually just allows the plant to rebound and doesn't do much for them the next day. Watering in the mornings gives them the water to help prevent from wilting in the first place.

I also do a 'primer' watering before the actual watering. An exaggerated example would be if I had a plant that took a gallon of water. If I pour the gallon of water all at once, even slowly, most will end up running off. But if I give the plant 4 cups of water first and then wait a five minutes before applying the rest of the gallon, the water penetrates the soil more and is less likely to run. That first 4 cups breaks up the dry soil which is actually quite water repellent at first. For me, this usually means walking through the beds with the watering can or hose and giving everything a rather short drink and then going back through and giving the rest. This is especially important if I am using fertilizer or worm juice augmented water, I would hate for all that goodness to just run off and not actually get to the plant's roots where it does the most good.

As for shade tricks, one that I have used from time to time is a pruning. If I have an errant shrub branch that needs to be removed when I am putting in a new plant, I will clip that branch and then 'plant' it next to the new addition so that it leans over the new one. The leaves on the limb will shade the plant from the high afternoon sun and as the leaves dry and drop, they gradually expose the plant to more and more sun and help to harden off the plant.