Contributed by Matt Barto

Pinus palustris Natural Range

While plenty of rare and unique trees make their home at the Morris Arboretum, one in particular struck me during my very first visit to the garden years ago. That tree was longleaf pine (Pinus palustris). I had heard of longleaf pine- a tree of the south- but was rather shocked to see it growing near Philadelphia in zone 6, hundreds of miles out of its growing range.

Turns out, longleaf pine technically shouldn’t be growing at the Morris Arboretum at all! Longleaf pine is native to the southeast US in zones 7b to 10, from the edge of Texas, sweeping across the south and up the coast to the tip of southeast Virginia. It’s quite remarkable to see such a mature specimen growing so well in the cold climate of Pennsylvania! This plant was received and planted by the Arboretum in 1934.

Pinus palustris - Grass stage
Credit: Jean Everett

Native Environment

In the wild, longleaf pine is native to dry, sandy upland soils including sandhills and flatwoods. The species name “palustris” means “of the marsh”- however this was a mistake made by the botanist who named the species after seeing native longleaf pine groves being flooded temporarily by a river in winter.

A Unique History

Longleaf pine has an interesting ecological and cultural history in the south. Before European colonization, there were approximately 90 million acres of longleaf pine ecosystems. However, because the longleaf pines were so valuable, forests were stripped of trees over a period of hundreds of years for their resin, turpentine, and timber. Today, only about 5% of these forests remain, and there are many restoration efforts being made to regenerate ecosystems not only for the longleaf pines, but for the accompanying plants and animals that grow underneath and alongside. 

Pinus palustris Young Tree

Growth Habit & Form
Longleaf pine is unique amongst our native US pines due to its characteristic “grass” stage  when a single stem emerges with long, drooping needles that resemble an ornamental grass. In this stage it develops a taproot that can penetrate downward up to 10 feet in length. During this grass stage, longleaf pine is especially slow-growing and resistant to natural wildfires (which used to be common) due to its heavily protected and large apical bud.

Pinus palustris - mature tree

As it matures, side branches develop and young trees resemble saguaro cactus in appearance. Trees develop an open, yet narrow crown, with old age and produce fairly large and prickly pinecones. Longleaf pine is one of our longer lived eastern pines- living up to 250 years or longer.

Next time you’re at the Arboretum, take a trip northeast of the Rose Garden to see the mature longleaf pine and view a piece of Southern pride!

In the fall of 2017, Jess Slade, the McCausland Natural Lands Horticulturist traveled with colleagues to coastal North and South Carolina where collections of this species were made.