When Robert and Susan Roati moved into their home near Reid Park 25 years ago, they were faced with a pretty bare and overheated backyard.

“It’s awfully hot back here,” says Robert Roati about the microclimate behind the house.

They started cooling things down by adding trees, eventually planting 14 of them.

They picked up baby mesquite, palo verde and carob specimens from Trees for Tucson, a Tucson Clean & Beautiful program, at one of its occasional sales at the park.

Fifteen years ago, they bought a five-gallon mesquite at a discounted price through Tucson Electric Power in a Trees for Tucson program.

That tree now nicely extends over the roof and keeps the west side of the house cool on hot summer days.

The couple’s four trees are among the more than 100,000 that Trees for Tucson has distributed since 1989, including in the program with TEP and Trico Electric Cooperative.

Trees for Tucson recently announced its tree selection for 2015 and a change that allows people to buy several trees to shade their homes, reduce their energy costs and improve air quality.

HOW THE PROGRAM WORKS

TEP customers or Trico Electric members can order as many as three five-gallon native or heritage trees, including fruit species, through their respective utility.

TEP customers pay $8 per tree. Trico Electric members pay $15.

In comparison, Civano Nursery offers similarly sized trees for between $28 and $60, although five-gallon trees are rarely available.

Trees must be planted on the south, west or east side of the home where it’s the hottest. Buyers also must agree to plant the tree no farther than 15 feet from the house, depending on the tree’s mature size, so that it can provide shade to the structure.

The list of tree species constantly changes, depending on what the program can get from local vendors in different times of the year.

Also, the program may run out of a particular species for the year.

Three- to 5-foot trees are delivered in about four to six weeks from ordering. Planting and care instructions are included.

WHY THESE TREES

All of the trees offered in the program are deciduous, meaning they shed their leaves in the winter. This allows the sun to warm the house when it’s needed.

They also grow as multi-trunk trees, if pruned that way, which adds to their shade-providing profile.

“When you think about strategies to shade your home ... you need a series of shade structures,” says Katie Gannon, Trees for Tucson program director.

A tall tree with a canopy can shade the roof, while a multi-trunk tree will cast shade on walls and windows. A low, shrub-like tree will cover more of a wall.

Gannon says she hopes offering fruit trees will encourage residents in traditionally low-income or traditionally Hispanic neighborhoods to participate.

These residents might be willing to buy trees that provide food as well as shade.

Trees for Tucson tries to offer species that are currently popular, which right now are natives and heritage fruit trees.

What Roati likes about the trees he got through the program is that they require little attention once they’re mature.

“After a couple of years, they just grow themselves,” Roati says. They do need trimming to shape them into shade trees, “but at a certain point you just say, ‘Go, tree. Do your thing.’”

TREE FEATURES

Arizona Pistachio Nursery is one of several vendors that provide plants for the program. Assistant manager Tim Bittick describes six of the species Arizona Pistachio provides.

Red Push pistache. Bittick is most familiar with this non-native species, which has been locally hybridized for more than 20 years. The single-trunk tree has non-invasive roots. Red flowers yield red berry seeds, which turn pale green before ripening to red again. It doesn’t produce nuts. Its fall leaves range from yellow to orange to beet red.

Catclaw acacia. This shrub can be trained to grow as a tree. It has large thorns and ball-shaped yellow flowers.

Foothills palo verde. Naturally found on Tucson hillsides, this small palo verde grows slowly and issues several large branches from the main trunk. Thorns are found on branch tips and it blooms yellow flowers.

Blue palo verde. This is Arizona’s official tree and is naturally found in sandy washes. It requires a little more water than the foothills and thorns are larger. It has yellow flowers and bark that has a tinge of blue.

Velvet mesquite. Smaller than its South American cousins, it also handles the cold better. It has big thorns on new growth and provides many low branches.

Desert willow. Also naturally found in sandy washes, it grows more like a bush with a deep, aggressive root system. It will grow wider than taller unless trained through pruning. Its light pink flowers have yellow and purple centers.

Pomegranate. Civano Nursery provides three heritage species for the program. Two are from old plants in downtown; the third is from a specimen in the ghost town of Ruby that still thrives. Co-owner Nick Shipley says the plant will grow as a multi-trunk tree about 12 feet tall. Summer orange flowers will yield fruit that ripens in the fall. Prolific suckers will need trimming; otherwise, it’s easily maintained in heat and cold.

Trico is offering two other trees:

Netleaf hackberry. Twisty branches add a sculptural element, making up for its non-ornamental flowers and small red berries, according to the University of Arizona Cooperative Extension.

Fig. Heritage fig trees provide two harvests, one in late spring and early summer, the second in the fall, according to the extension.

Contact Tucson freelance writer Elena Acoba at acoba@dakotacom.net