Pinus monophylla Seeds | Single-leaf Pinyon

Single-leaf pinyon with individual curved grey-green needles and small round cones — Single-leaf Pinyon (*Pinus monophylla*): Pinaceae, the only pine with one needle per fascicle, of the Great Basin.

LATIN NAME: Pinus monophylla

COMMON NAME: Single-leaf Pinyon

Plant Profile

Single-leaf pinyon is the only pine in the world that carries its needles one at a time, and that alone makes it worth knowing. Where other pines bundle two, three or five needles in a sheath, this one has a single stout, curved, grey-green needle, four to six centimetres long, held individually along the shoot.

The tree is small by pine standards, five to ten metres, often shorter, with a short trunk, a rounded crown and bark that stays dark and furrowed. It grows in the dry ranges of the Great Basin and the Mojave margins, from Utah and Nevada into California and Arizona, usually between fifteen hundred and twenty-five hundred metres, in open woodland with juniper. Its cones are small and round, five to eight centimetres, and they hold large, wingless nuts that are sweet and rich.

Science & Biotechnology

The single needle is a genuine anatomical oddity, and it has been used in studies of pine evolution: the fascicle sheath is present but the needle number is reduced to one, and the trait appears to have arisen relatively recently within the pinyon group. The species is also a case study in animal-mediated dispersal.

The seeds have no wing and do not travel on the wind; they are carried and cached by pinyon jays, scrub jays and Clark’s nutcrackers, and the trees that survive are largely the ones the birds forgot. That relationship is close enough that the jays’ caching behaviour and the pine’s cone structure have been studied together. Pinyon-juniper woodlands have expanded and contracted with climate for thousands of years, and the species is now under pressure from drought, bark beetles and fire suppression.

Uses & Benefits

The nuts are the main crop: large, pale, sweet and oily, they were a staple food for Paiute, Shoshone and other peoples of the Great Basin, harvested in autumn, eaten raw, roasted or ground into flour, and they remain a commercial crop under the name pine nuts.

The wood is dense and resinous and was cut for charcoal and for mine timbers, and the tree is now more valued standing, for its nuts and for its role in the woodland ecosystem. In the garden it is a slow, sculptural small tree for a dry, sunny site, good in a gravel garden or a xeriscape, and it tolerates cold and poor soil far better than most pines. It is also a fine subject for bonsai, where the short needles and rugged bark are assets.

Growing from Seed

The nuts need cold, moist stratification, six to eight weeks at four degrees, and they should be sown in deep pots because the radicle goes down fast. Use a gritty, free-draining mix, cover the seed lightly, and keep the pot outdoors after germination so the seedling grows in natural light.

Germination is usually good with fresh seed and poor with old. The seedlings are slow and should be grown on for two or three years before planting out into a dry, sunny site with sharp drainage. Do not water heavily or feed; rich conditions produce soft growth and shorten the tree’s life. Protect young trees from deer and rodents, which will browse them to the ground.

Our Take

A one-needle pine with excellent nuts and a bird-dependent sex life; a connoisseur’s tree for dry ground. A tree for a gravel slope and a dry summer, not for a watered lawn.

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