Branch structure of a mature ponderosa pine in Leavenworth, WA. Photo by Paula Dinius/WSU Chelan County Extension

Ponderosa Pine, Pinus ponderosa 

When was the last time you selected a native Washington conifer for a landscape planting? Let’s bring a few back into the landscape where appropriate*.

If you’re on board with that idea, then ponderosa pine is a fine tree to ponder planting where space is available*.

Ponderosa pines are BIG trees: the Washington State Champion Ponderosa Pine, growing near Trout Lake, Washington, in the Gifford Pinchot National Forest, is 7′ in diameter and 202′ tall! Heights of 80′-100′ and diameters less than 3′ are more common, however.

Ponderosa pine is an emblematic tree of the American West, as well it should be since it is found in every state west of the Mississippi except Alaska and Hawaii. Ponderosa pine ranges within those states, however, are scattered by changes in elevation, soil type, and soil moisture. These scattered populations have developed into slightly different varieties. Pacific ponderosa pine (P. ponderosa, var. ponderosa) is the variety typically found in Washington State.

The needles are 5-10″ long, dark olive-to-yellowish green, and are usually bundled in fascicles of three, occasionally in fascicles of two. Buds are cylindrical, red-brown in color, and less than 1″ long. Cones are oval, 3-6″ long, and often bunched together in groups of 3-5.

Mature ponderosa pine bark. Photo from Bugwood.org

A most distinctive feature of the tree is the bark: heavily furrowed and rich black-brown on vigorous young trees, mature ponderosa pines exhibit a thick, fire-resistant bark that separates into broad, orange-colored plates–an iconic and defining characteristic of the tree. On warm days, light scents of cinnamon or vanilla may emanate from the bark, a delightful identifier.

Although ponderosa pine prefers full sun, performing best when planted in deep, well-drained loam soils, it can and does thrive in sub-optimal conditions throughout its range where soils may be rocky or sandy and where moisture is more limited. Note that, typical of pines, it will not thrive in wet, heavy, clayey soils. Pests and diseases, such as bark beetles, pitch moths, rusts, needlecast, and root rots, can thwart the health and longevity of any ponderosa pine, particularly those under stress.

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Newly planted ponderosa pine in Olympia, WA. Photo by Ben Thompson/DNR

 

Have we convinced you to plant a ponderosa pine where you live? Take a bit of advice from WSU Chelan County Extension Agent and ISA Certified Arborist Paula Dinius:

“The three most important things to remember about planting this tree and most other native conifers are:

  1. Make sure you have enough space
  2. Make sure you have enough space
  3. Make sure you have enough space!”*

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*Lack of available planting locations that are physically large enough to accommodate the mature size of PNW native conifers is perhaps the primary reason that more of these lovely trees are not planted in urbanized Washington landscapes. Some cities are considering regulations that require larger planting spaces in development designs, while others have passed ordinances requiring percentages of trees planted to be native species. While these successes are helpful, the fact remains that many of our existing street tree planting sites, parking lot islands, and urban yards have not been designed or built to accommodate large native tree species. And that, to turn a tree cliché, is a tough nut to crack.

Does your city have conifer-friendly ordinances and policies, or is your city is considering developing them? We’d like to hear about it. Contact the DNR urban forestry program at urban_forestry@dnr.wa.gov.