Houston’s trees are showing off.

They’re popping with sunshine yellows, luxurious reds and rare, breathtaking bright oranges. And their performance, which peaked last week, has been turning heads: While it’s not totally atypical to see these colors in Southeast Texas, it is unusual to see so much.

When a leaf is about to die, there’s a battle for which color will reign supreme in its final days.

As the days become shorter and the weather is that perfect balance of wet, dry and chilly, that’s when the clash begins. Chlorophyll in the leaves has a natural green pigmentation, which overpowers other parts of the leaf structure containing the yellows, oranges, reds and browns.

Autumn’s decrease in sunlight is a key reason for the explosion of leaf color, said Ryan Bare, research associate with Houston Advanced Research Center who works with the Texas A&M Forest Service. Without the full sun, photosynthesis and other processes stall, causing chlorophyll to dissipate. This leaves the tree with less energy to stay green, giving the leaf’s other colors time to express themselves — even if it’s only for a week or so.

On HoustonChronicle.com: Zombie trees invade Houston landscapes

“A lot of it is driven by temperature and the amount of daylight,” Bare said. “If you get more sunlight in the fall, it’s beneficial to fall color. So years with less overcast, you get better expression in the leaves. Depending on the composition or amount of pigments, that’s what drives the color of the leaf. In general, one leaf could go through a transition of colors before falling off.”

While Houston’s September was its hottest on record, averaging 83.9 degrees, the last six weeks have been what meteorologist Matt Lanza calls “Goldilocks weather.” The first cool morning was Oct. 11 when temperatures dipped down to 52 degrees, and Thursday ended a 14-day streak of low temperatures below 55 degrees.

“It’s pretty typical for late fall or winter, but it’s timed perfectly for fall color here,” said Lanza, managing editor of Space City Weather. “It takes a fine balance of the right combination of factors to produce fall color, and down here, it requires more factors of those working really well together. This fall has been perfect.”

So, which trees are expressing themselves the most?

Red maples, native to Texas, are well-known for their fall foliage. Different oak species, especially the Shumard oak, will turn yellow, orange or a rusty brown-red. Bald cypress tree leaves will fade to a coppery orange and brown color before falling, and sweetgum, sometimes called red gum, is famous for its green-to-yellow-to-red coloration and star-shaped leaves.

At the Houston Arboretum and Nature Center, locals and visitors alike have noticed the fast changes in tree color, said Christine Mansfield, marketing and development manager. Last year’s fall season had the right conditions for changing leaves, she said.

On HoustonChronicle.com: Is this a flower or a weed? A budding gardener finds her footing.

“Sometimes the more vibrant trees aren’t native, like the Chinese tallows. They can get really invasive and sometimes choke out the native species,” Mansfield said. “It’s beautiful, but it doesn’t always belong here.”

The arboretum is home to native wildflowers, prairie grasses and other plants that are experiencing their second bloom now, she said.

There’s the Virginia creeper, a vine that turns red after it climbs a tree, giving it the appearance of having a red trunk. Gulf muhly, a perennial grass with fluffy tops, can be found at the park’s Loop 610 entrance and is currently turning pink. Oakleaf hydrangeas have started turning red, orange and purple, and the shagbark hickory trees are showing spots of yellow in their five-pronged leafs.

Fall color has peaked in most parts of the state, leaving mounds of crunchy, yet colorful, leaves in the yard.

The fallen leaves keep nutrients in the life cycle of a tree, Bare said. The more organic matter in the soil, the better it will be at holding water, which will cut down on irrigation needs and cost. Decomposed leaves also promote natural growth and reduce the need for fertilizer.

He suggests mowing them rather than raking.

“The compost and mulch will break up and help to build the soil profile for the lawn.”

julie.garcia@chron.com

twitter.com/reporterjulie