For a few hours every Saturday, Dr. Peter Galpin would tend to the jacaranda trees lining Haleakala Highway to honor and continue his son’s efforts.

About a decade ago, King Kekaulike High School graduate Aki Galpin organized his Troop 14 Boy Scouts and partnered with the Maui Outdoor Circle to plant 21 trees as part of an Eagle Scout project.

For months, the trees were nurtured until they were strong enough to survive by themselves, but once Aki graduated and moved out of state, Peter Galpin picked up the responsibility.

“I would really feel like it was just me and him watering the trees again, even though he wasn’t there, he was on the Mainland, but I felt very close to him when I was out there taking care of the trees,” Peter Galpin said. “I can remember the day we were all down there, must have been 30 or 40 people. So every time I drive by, I would think about him and wonder how he’s doing. And like most organic life, sometimes they struggle, and I noticed the trees looked kind of dry and I just wanted to start watering them.”

One of those trees finally bloomed this season, recalled Ernest H. Rezents, who was also involved with the Eagle Scout project and is an International Society of Arboriculture-certified arborist and retired professor of agriculture from the University of Hawaii-Maui College.

Despite the departure of Peter Galpin — the doctor retired and moved to Canada this week — Rezents said the trees should be fine provided they get enough water.

“They used to get a lot of water, but there is a lot of grass competing with them as well. Grass is very competitive for water and nutrients,” Rezents said. “In reality, it’s survival of the fittest. Those are beautiful trees. I suggest keeping the grass away, put some fertilizer and maybe add some extra water. Especially with the drought we’ve been having, they would do much better.”

Noticing the slow developments in his own rare species of jacaranda colvillea racemosa in the front yard, Rezents said that the trees are “very long lived” and can take about nine to 10 years before they even produce their dark-blue-and-purple flowers.

“Last year it had a few blooms; this year was profuse,” he said.

Upcountry in springtime means jacaranda trees in full bloom, lining the roadways in Kula and Makawao, Rezents said. Many of the purple blooms reflect small pieces of history and have been nurtured to preserve stories like Galpin’s.

For example, the jacaranda trees along Lower Kula Highway were inspired by Keokea resident and Maui County’s first mayor, Elmer Cravalho, who in the late 1950s requested that jacarandas be planted in Kula, Makawao and Pukalani.

More were planted along the road passing Rice Park under Mayor Hannibal Tavares, who was Maui’s second mayor from 1979-1991.

If started from a seed, the 25- to 50-foot trees can take up to seven to 15 years to reach their full growth, and then can survive up to 50 to 75 years.

Ideal environments include cooler temperatures or higher elevations, as well as rich soils and water. Rezents hopes that this summer’s record-breaking heat won’t affect the jacarandas’ health.

“We’ve had these types of seasons before, and I’m not sure how this might play into global warming, so we’ll just have to see what happens,” he said. “They’re just beautiful trees. Maybe if it’s too hot, they might not bloom as well, but I know up in Kula they do very well, even more so than in Makawao.”

* Dakota Grossman can be reached at dgrossman@mauinews.com.