Pinus aristata aka Bristlecone Pine

Pinus aristata is the Rocky Mountain bristlecone pine. This evergreen tree belongs to the pine family, Pinaceae. It grows in mountain areas of Colorado, New Mexico, and Arizona. Its native sites have dry, rocky ground and cold weather. Some trees live for thousands of years. One Colorado tree reached a recorded age of 2,435 years.

In gardens, it grows 8–20 feet [2.4–6.1 metres] tall. Its spread reaches 10–15 feet [3–4.6 metres]. Larger trees may reach 40–50 feet [12.2–15.2 metres]. Growth is very slow, and young trees look like shrubs. The crown stays dense, with an uneven, rounded or flattened shape. Harsh sites can twist both the trunk and branches. The trunk may reach 3 feet [0.9 metres] across. Gray to reddish-brown bark has shallow cracks and flat ridges. Young twigs start orange-brown, then darken with age.

The short needles grow in tight groups of five. Their green to blue-green color lasts through winter. They feel prickly and give off a scent. White resin spots dot the needles and can resemble scale insects. Needles may stay on the tree for more than 15 years. Male and female cones grow on the same tree. The small flowers have little value for garden display. Sources place flowering in spring or summer. Young female cones have red to purple tones. Mature cones turn dark purple-brown and have no clear stalk. Each cone scale ends in a sharp point. Fallen cones can hurt bare feet.

Give this pine full sun and soil that drains well. It grows in poor, dry, rocky soil and tolerates drought. It also accepts loam and clay where drainage is good. Acid and alkaline soils both suit it. Sources place it in USDA zones 4–7. It does not cope well with polluted air. Reports differ on wind tolerance, so shelter from drying winds makes sense. Its slow growth suits rock gardens, patios, and pots. It also works as a lone accent or screen. Deer tend to leave it alone, and imperial moth larvae feed on it.

Pests include bark beetles, aphids, and needle scale. White pine blister rust and dwarf mistletoe can cause problems. The tree also has a high fire risk. Its seeds are edible raw or cooked. They contain oil and have a mild resin taste. The needles can provide tan or green dye. The supplied evidence does not establish a species-specific toxicity rating.