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TREES, PLEASE: Hot-Hued Trees for Sizzling Summer Daze

Royal Poinciana. Attribution: John Redcliffe SA BY-CC 2.0 CC

By Robin Rivet.

Summers in San Diego increasingly remind me of places I used to live; but I’m no snowbird. I fled the east coast loathing brutally hot summers, not frigid cold. Sadly, what used to be unbearably hot weather for only a day or two in July - October here, seems to be evolving into multiple weeks of stifling SoCal temperatures, and our trees suffer along with us. Some California native plants can partially shut down to protect themselves from desiccation during hotter conditions. However, there are some non-native species that flourish as the mercury rises. Better yet, some of these non-natives sport eye-popping, fire-inspired color, even during San Diego County’s hottest heat waves.

Perhaps you’ve noticed copious 7” spheres of orange, rosy or ruby-red flowers adorning modest-sized freeway trees. These are likely red-flowering gums or Corymbia ficifolia. Throughout the summer, along Interstate 8 in Mission Valley, they appear as if an artist’s paintbrush daubed globes of burnt-red pigment onto branches that otherwise go unnoticed most of the year. This tough, compact tree is closely related to eucalyptus, although few residents realize they are kin. These make striking accent specimens for locations across Western Sunset Climate Zones 8-24.

Red Gum Nut Flowers. Attribution: John Redcliffe. CC BY-SA 2.0

Despite being listed as a utility-friendly species for our region, my anecdotal observations suggest that weeping bottlebrush, Callistemon viminalis, gets taller than most tree specifications imply. The aptly named bottlebrush shaped flowers occur most any time of year, but they are especially showy during warm weather, when the entire tree colors up. Repeat blooming can be stimulated all summer long with some periodic deep watering. These intense-red, red-violet and scarlet inflorescences may take your breath away, while their pollen and nectar invite myriads of bees, butterflies and hummingbirds into your garden spaces during summer heat waves.

Pomegranate, Punica granatum, flowering may slow as summer progresses, but their scarlet-skinned fruiting orbs begin to swell, conspicuously hanging onto bright green foliage that seems indifferent to thermometers. Of hundreds of cultivars, Angel Red™ might be the most alluring visually. Few trees offer edible fruit and bold color, while also tolerating furnace-like temperatures, like these health-boosting fruit trees.

Stunning, bright orange or salmon-colored capsules envelope the tiny, yellow flower parts on this tree species. In summer, it begins to appear as if a giant coral-colored bougainvillea fell out of the sky onto the top of its umbrella-shaped canopy. Not only is this species a stunner, Chinese Flame, Keolreuteria bipinnata, and its relative K. elegans, Flamegold, are easy to grow and offer wonderful shade to hide under during sweat-inducing weather.

Imagine a jacaranda, only with profuse, neon, cherry-red blooms during the meanest dog days. It’s no coincidence that Delonix regia is called “Royal” Poinciana (photo at top) as this species might knock off your sunglasses. Although it’s not common yet in our region, it can grow here, particularly in the warmer, inland thermal belts where tropical trees seem to be acclimating better than Sunset Zone descriptions might suggest. This super-flamboyant species may be especially suited to our climate-warming trends. Let’s be prepared.

Member Robin Rivet is an ISA Certified Arborist WE-7558A – contact her:

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