looking for pretty flowering tree to shade lawn

We are looking to plant a pretty tree to shade our lawn inthe summer time. Deciduous, blue, purple or pink. looking for something unusual, but not invasive. we are in zone 9.

How large an area do you want to shade? Are you looking for bright filtered shade so that you can grow other plants under it? Deeper shade? Will you be growing grass under the tree? What kind? Except for varieties of St. Augustine grass, most grasses grown in the greater San Francisco Bay Area won't grow well in shade.

I don't know what zone you're in but this is the most beautiful tree I've ever seen. It's called a Jacaranda Mimosifolia.
http://davesgarden.com/guides/pf/go/1254/

Jacaranda was the first thing that came to mind for me too. If we get a rough winter, you may want to give it a little protection until it gets established, but it should do fine for you. It's mostly evergreen though so it doesn't quite fit your criteria, but it has very lacy leaves so maybe that would be OK.

Another couple trees you could consider are:
Chilopsis linearis http://davesgarden.com/guides/pf/adv_search.php?searcher%5Bcommon%5D=&searcher%5Bfamily%5D=&searcher%5Bgenus%5D=chilopsis&searcher%5Bspecies%5D=&searcher%5Bcultivar%5D=&searcher%5Bhybridizer%5D=&search_prefs%5Bblank_cultivar%5D=&search_prefs%5Bsort_by%5D=rating&images_prefs=both&Search=Search This one's deciduous and very beatiful. I'm not sure if it'll do well in the middle of a lawn though, it's one of those plants that doesn't really like much summer water once it's established so the lawn water may kill it.
x Chitalpa tashkentis: http://davesgarden.com/guides/pf/adv_search.php?searcher%5Bcommon%5D=&searcher%5Bfamily%5D=&searcher%5Bgenus%5D=chitalpa&searcher%5Bspecies%5D=&searcher%5Bcultivar%5D=&searcher%5Bhybridizer%5D=&search_prefs%5Bblank_cultivar%5D=&search_prefs%5Bsort_by%5D=rating&images_prefs=both&Search=Search&searcher[genus]=X%20Chitalpa This one is an intergeneric hybrid between Chilopsis and Catalpa and would tolerate more water than Chilopsis would, so it might be a better option given the lawn situation
Chorisia speciosa: http://davesgarden.com/guides/pf/go/55678/
Tabebuia impetiginosa: http://davesgarden.com/guides/pf/go/1724/
These last two should do OK in your climate once established, but you may need to protect them on frosty nights (if you get any) for the first couple years.

I thought of jacaronda too. I love these trees. its a consideration, I like the lacy leaves. Do you know how fast the Tabebuia impetiginosa grows. I'm also looking for something fast growing does the tabebuia grow fast of slow and what do the leaves look like? The lawn also might suffer a bit but in the summer it is so hot we don't sit on it anyway. I'd like to create a little shade canopy about 12x12 feet so possibly a shrub that could be trained as a small tree. tall enough to walk under. fast growing is important because my grandmother is the one whose idea it is and she is 88. Got get big enough for her to sit under before she goes : ( I was thinking of a princess flower but I'm not sure if that grows fast enough or would like all the water.

I don't know how fast the Tabebuia grows, I have one but it's in a pot since I'm not sure if it would like our frosty nights, we're a bit colder than you in the winter. If you look at the link to Plant Files, there are a couple pictures in there that show the leaves.

You might also consider Vitex agnus-castus http://davesgarden.com/guides/pf/go/1188/ It can be grown either as a large shrub or small tree depending on how you prune it, and I think it grows reasonably fast. I'm not sure how it'll like the lawn water--it is rather drought tolerant, but there are some things that are drought tolerant but can also be happy with more water, and since it's grown in a lot of areas of the country (not just the dry western part!) I think it probably tolerates water pretty well (and might grow faster if it gets more water than I give mine) There are always crape myrtles too, but everyone has those so I'm not sure if you'd be interested or not! Princess flower would probably work too, I don't know if they grow fast or not, but they're not native to this area so I think they'd probably be fine with the water.

PS how hot does it get in Santa Cruz that you can't sit outside? Try coming a little farther inland sometime next summer and you'll feel what too hot feels like! LOL

Going back to whether Tabebuia would be fast growing--I bet it would be. It's the tree that ipe wood comes from, and it's being touted as better, more renewable/sustainable than some other hardwoods. Generally the lumber trees that are considered better for the environment are ones that grow fast, so you're not cutting down old growth trees that will take forever to regrow.

We love our Chitalpa trees. They are 4-1/2 years old and the biggest one is about 12 feet - most of the growth in the 2nd and 3rd years. We planted this one in a sort of raised bed because our soil is rock hard clay and also it is in the center of our terrace. It has done the best of all.

We reevaluated the lawn space and i think were looking at something smaller than I originally thought. Probably better to get a shrub that can be trained as a single trunk tree. that we can keep pruned to about 10 feet tall and 8 feet wide hoping to get a canope shape. It funny I think maybe I should jump on ecrane3s thread about a water tolerant shade shrub seems like we might actually be looking for the same thing.

I think I needed something a little different than you--your shrub will be getting consistent (but presumably not too terribly excessive) water from your lawn watering. My neighbors alternate between not watering at all, and watering every single day which is way too much, so I needed something that could tolerate runoff from their excessive everyday watering--I hope you're not doing that to your lawn! And I also wanted something that didn't need to be wet all the time, so when they weren't watering the lawn I wouldn't have to be out there every day watering. So while the shrubs that were suggested for me might also work in your situation, you're much less limited than I was.

I'd really recommend looking into Vitex, it definitely would have the size and growth that you want, plus it has pretty flowers.

If youre interested in the Jacaranda I have some I started from seed for trade. They range from 1-3 feet. Im hoping to plant the biggest one in my own yard. Its a beautiful tree.