Water it whenever the soil around the roots is dry down about 2" - stick a finger in to the second knuckle and see. Don't do this on a rigid schedule, but according to the weather and eventual experience - if it's dry, water, if it's damp, wait another day or so. And don't just give it a quick once over with a hose - either use one of the soaker rings, or set the hose to trickle, and leave it there for half an hour or so - you need to apply the equivalent of 4-6 gallons of water, but very slowly, so the ground is wet to the bottom of the root ball. You also need to get the area you want the roots to grow into wet, to encourage the roots to grow out into it - if all the water is right next to the trunk, that's where the roots will stay. Don't rely on the lawn sprinkler system to do for a newly planted tree - it's not enough until the tree is established. Mulch will help keep moisture in the root area and will keep the soil cooler - mulch with any natural mulch (avoid the dyed ones, they look awful), no deeper than 4", as widely as you can (at least 3' diameter, 6' is better), and put no mulch in the inch or so around the trunk. You can smother the grass around the tree - which is competition for the moisture and nutrients - by laying down flattened cardboard or 4-6 sheets of black-ink newspaper layered with no gaps, under the mulch. Just make sure all the edges are covered, as the paper can wick moisture out of the soil if exposed to air. As an alternative, you can kill off the grass with Round-Up, but be SURE not to do this on a breezy day, so NO RU gets on the leaves. I fully agree with Jean001, above - taking a tree from a pot where it probably got daily watering, putting it in the ground, with a different structure, etc, which is a shock to it anyway, and NOT watering it is not a good idea. WATER for at least a year, tapering off in the second year, but water in long dry spells even in the third year.

I know I posted that I wanted one back in 05 but since then I have had a chance to observe how they take the winds that roar through here in fall and winter. They are pretty brittle and break often enough that I decided against one as gorgeous as they are in spring. Crape Myrtle is my choice for flowering tree. Too small to cause any damage if they blew over. One of my young ones with a trunk as thick as my thumb got blown over because the stick broke in the wind. I just straightened 'er up and restaked. Didn't hurt it at all. It's a nice darkish purple. I also have red, hot pink and lavender ones. They also have a bonus of coloring gorgeously in the fall. For big shade I picked London Plane and Sycamore. I never got around to staking one of them. It grew so fast it didn't matter. Both kinds are very wind tolerant.

Bob,Sacramento might already be Jacaranda friendly,after all you have seen large ones you said. And i know Capital park has the states largest Erythina crista galli and a few other tender trees.And if your well into the city, even more urban warming to go with the blazing summers they love. Jacarandas for the most part survived 1990's big freeze in the bay area..a normal Sacramento winter in comparison is a walk in the park.

I had a seedling pop up near my Jacaranda amongst the rocks about six years ago. I pulled it up like a weed, as I usually do. This time the the root came up in its entirety...no breakage so I planted it over on the hillside on county property. It was about two feet tall at the time. It bloomed I believe it's third year also at about ten feet tall. It didn't bloom the next year however. It's tall and spindly now...about 20 feet but bloomed nicely this year. As it fills out, I expect it to be a nice tree. -Ron-