When it comes to a new plants in a landscape I cringe when I hear... "Well, I have a sprinkler system, so my plants will be fine." NOOO. They might be, but a hands on approach really is best.
By watering by hand you're able to best care for your plantings. It is more intimate. You'll be able to quickly detect subtle changes in appearance that may indicate too much water or not enough. You will more quickly see signs of stress from heat or feeding insects.
If you have had new plants recently planted, the 3-2-1 approach is a great way to help them make the transition and settle into a healthy growth pattern. What's 3-2-1 mean?
3-2-1 is a baseline method of watering. It simply means to water 3 times the first week, twice the second week, and once each week from then on.
When watering, it is best to water around the crown. Directly under and around the center portion of the plant. Think of the containers the plant came in, or root ball. The root system was within that space. As you water, that is where the watering needs to go. Keeping this area damp, not flooded is the goal.
The 3-2-1 method is simple method to outline a pattern of care. This certainly can change due to higher temperatures or supplemental rains. Regardless, don't assume you're sprinkler is going to do the right watering. That could lead to heartache, loss, and extra labor costs to replace warranty materials.