I always water in well when I've finished planting seedlings or plants. Then keep an eye on the weather and water again as needed if it hasn't rained until they are well established. Annuals will need their own kind of attention, but with perennials, trees, shrubs they aren't considered established until at least one year has passed - nothing newly planted is drought tolerant.

Mulching over your planting bed, up to and around our plants, will help to keep roots cool and conserve moisture.

Ditto to what morz said. Keep an eye on the plants, water when necessary, and mulch. It does take a bit of babysitting when they are little to get them established, but it's worth it!

:)
Dee

I may be more solicitous than necessary, but I water every day after I plant out.
til they seem to be standing up and perky :) and then I reduce watering to every other day, and gradually taper off to when is necessary.
I also shade them after transplanting.
I get in the dollar store when they have them - small wire wastebaskets, which turned upside down prove good protectors from a blazing sun and critters.