Tim Steller’s column: Climate reality bites Tucson’s citrus tree tradition

Local water conservation pioneer Brad Lancaster has been using some of the concepts North advocates. He told me he has been noticing at his home the growing stress, especially on exotic and non-native trees.

“I was initially distressed and disturbed by that,” Lancaster said. “Then I thought, ‘OK, let’s shift how I’m thinking about this. Can I put in different plants that would do better for these changing conditions?”

“I replaced some fruit trees with edible cactus like nopal or the Opuntia ficus indica (Barbary fig).”

Lancaster has been creatively using shade and, of course, the water harvesting he’s known for, to change how he gardens. He has a Valencia orange tree that has been doing OK, but has planted a successor beneath it: A native Condalia that produces berries and is thriving.

“I’m slowing pruning back the citrus to make room for the Condalia and eventually I will take the citrus out,” he said.

He’s even phasing out his summer vegetable gardening, limiting plantings to heat-adapted tepary beans, purslane and amaranth.

“I’ll plant those with the rain, and if there’s enough rain to germinate, I have a garden. If we don’t have enough rain, I don’t have a garden.”

Decisions like this to go with the native and heat-tolerant plants are backed up by a change that the U.S. Department of Agriculture made in 2023: Tucson’s hardiness zone went from 9A, a zone where the average lowest winter temperature is between 20 and 25 degrees, to zone 9B, where the average lowest winter temperature is between 25 and 30 degrees.

This makes a big difference for deciduous fruit trees like peaches and apples, which require long stretches of cold weather below 45 degrees, along with a lot of watering, in our climate.