I would suggest Jacaranda-loves heat, provides nice filtered shade, and gorgeous blue/purple flowers in late Spring. Another beautiful flowering tree is the Hong Kong Orchid which has large heart-shaped leaves, is evergreen and flowers during the winter/spring. The flowers on the Hong Kong Orchid have a dark pink coloring and are huge!!! For trees that are as lush and beautiful as these two they are suprisingly hardy and easy to grow. Both are fast growing trees and will do well with a deep watering once a week during the summer once established. Jacarandas can grow to be over 40 feet tall, but can be trained to branch high to allow you to walk under or plant under them. Hong Kong Orchids aren't as numerous around here as they are in Southern California, but I've seen a few around Phoenix in the 20-30 foot tall range. Both trees are available at local nurseries and right now is a great time to plant.

Jacaranda would be my first choice :)

Easy

Mimosa, or
Royal Poinciana (Delonix regia) for more info click on the link below;

Here is a link that might be useful: Click Here

Sharon, take a look under the "Neem Tree" post for a pic of a Silk Floss tree in full bloom.

I like all the trees mentioned. But, each will have some drawbacks. Jacaranda can be cold sensitive, Orchid Trees can suffer a bit in our alkaline soils. Silk Floss have very thorny trunks. There is a thornless variety, but have heard mixed reviews on it. I love the Chinese Pistache, gives great shade, and fall color. Deciduous.

Thanks for all the suggestions! I have been thinking about a Jacaranda for awhile but lately have also been looking at the Chinese Pistache. I will go out to the nursery this week and see if they have anything I'm interested in. I live in Lake Havasu City, and we don't have a big choice of nurseries here. When I called one the other day they suggested a Sissoo tree. I have one in my back yard that has more than tripled in size in two years. I like the tree but I'm not sure if I want one in my front yard. The Sissoo is supposed to be deciduous too, but mine keeps most of it's leaves in the winter.

The winter lows in Havasu are warmer than in Phoenix so frost damage to either the Jacaranda or Orchid trees isn't something i'd worry about. Chinese Pistache are a beautiful tree, but are NOT a fast growing tree. The old purple orchid tree is the one that grows a ton of bean pods and can get salt burn during the summer. The Hong Kong Variety is sterile so doesn't have any bean pods so it's cleaner than the old orchid tree variety. I've had the Hong Kong variety in my yard for three years and it's hasn't shown any burning in the summer AND it's growing in full sun. I'm not sure what the selection is like at nurseries in Havasu, so you might want to pick a tree up on your next trip to the Phoenix area. There are a lot of new nurseries popping up in the northwest side (Suprise, Peoria) and they should have all the trees we've mentioned.

How about theses?

Cascalote (Caesalpinia cacalaco)
15+ x 15+ feet at maturity
Moderate growth rate
Full sun
Young trees are very thorny
Stunning yellow winter flowers followed by colorful read seedpods
Low litter

Sonoran Emerald hybrid palo verde
30 x 30 at maturity
Fast growing
Full sun
No thorns
Dense canopy with dark green, lush foliage
Bright yellow flowers in spring, few seed pods
Low litter

Evergreen Elm (Ulmus parvifolia)
30 x 30 at maturity
Fast growing
Full Sun
Semi-evergreen
Attractive bark

Chitalpa (Chitalpa taskentensis)
20 - 30' tall and wide at maturity
Leaves are 1/2" wide and 5-6" long
Full sun
No thorns
Showy clusters of pink or white flowers during warm months
No seeds
Deciduous in winter

I have a Hong Kong and it's gorgeous. When it does drop leaves they're big enough to pick up by hand! This picture is from last spring and since then it has doubled in size. I really like it. We also put in Chinese (evergreen)Elm and a Jacaranda. they're all nice trees.

Here is a link that might be useful: