Pinus sabiniana (Bull Pine, Grey Pine)


Michael's Opinion

Although it is often seen as a weed, I see potential in Pinus sabiniana as an extremely hardy plant for those tricky areas in a southern landscape with little moisture and a lot of heat. Personally I feel that the tree is much more beautiful than some have said, and its multi-stemmed structure should have a place in southern gardens. I believe that it would make a great accent or specimen planting, especially in xeriscape gardens where it will thrive. I would also like to acknowledge the incredible history this tree has with indigenous communities in the United States of America, and its importance to wildlife restoration and conservation.

Botanical Information

FamilyPinaceae
GenusPinus
Speciessabiniana
CategoryWoody
TypeTree (evergreen)
OriginNative to California, found in a five million acre range known as the Foothill Woodlands.
Ethnobotanical Uses
Disclaimer
Limited commercial use today, however, it was once an important tree to Native Americans who used its seeds, cones, bark, and buds as a food supplement and its sap, twigs, and needles in basket and drum construction. Today the seeds are still eaten by Native Americans in rituals and ceremonies. Early settlers used the sap for medical purposes. The wood is not valuable, but it has been used in railway ties. This tree is important in the preservation of the moth species Chionodes sabinianus as it feeds exclusively on Pinus sabiniana.

Details

USDA Hardiness Zone8
USDA Hardiness Ref.
Canadian Hardiness Zone7b - 8a
Canada Hardiness Ref.
RHS Hardiness ZoneH4 - H5
RHS Hardiness Ref.
Temperature (°C)(-12) - (-7)
Temperature (°F)10 - 20
Height12 - 21 m
Spread0.6 - 1 m
GrowthMedium

Description and Growing Information

General DescriptionA gnarly looking Pine that grows at higher elevations, making it incredibly drought tolerant. Multi-stemmed in form with long drooping needles, the perfect addition to a xeriscape garden where its colourful strobili and extremely large cones can be admired.
ID CharacteristicThe form of a mature Pinus sabiniana is multi-stemmed and irregular. You can identify the tree based on its huge rounded cones that often persist long after they have dispersed their seeds. Furthermore, the scales on its deeply furrowed bark will easily break away and reveal a dull brown colour beneath the grey of mature bark. The needles of Pinus sabiniana are very long and have a dull colour, but they twist slightly which gives them an interesting appearance.
ShapeSeedlings will sprout entirely perpendicular to the ground, with one main shoot. In these early years the tree will have a traditional conical shape. As a tree matures, it will begin to twist oddly and develop several forks within the trunk. A fully mature Pinus sabiniana is often multi-stemmed and spreading/irregular in form.
LandscapePinus sabiniana is not used very often in the landscape, except for naturalization efforts. It is seen as a weed because of its ability to sprout and establish in less than favourable environments. Wildlife habitat restoration is a possible use for this species, as the larvae of the moth species Chionodes sabinianus feeds exclusively on Pinus sabiniana. In addition, the tree provides food to several other animal species and therefore it could be a valuable specimen for wildlife attraction. Additionally, its drought tolerance makes it a prime candidate for xeriscaping.
PropagationThe best time to take cuttings from Pinus sabiniana is from mid winter to early spring, before new growth has emerged. Place the cuttings in an equal mixture of perlite and peat moss; the use of rooting hormone is recommended. The medium must be kept moist at all times, and to accelerate rooting you can place the cuttings onto a heating mat set to 20°C. Place your cuttings in an area with bright indirect light for best results. Unfortunately propagation by cuttings can take up to a year, therefore, seed collection and germination is the preferred method of propagation. Seeds can be collected as soon as they ripen, carefully remove the wings and soak them in water for 48 hours. After this time you should drain the seeds and allow them to air dry for a day. The seeds should then be given a stratification period of at least three and a half months. Post-stratification the seeds can be planted in a well draining media, the plants should be moved into a humid greenhouse for the first six weeks of germination; during this time the soil should be kept moist to the touch at all times. Once the first cotyledons appear the plants are ready to be moved out of the greenhouse and into a shade house, where they should be allowed to dry out completely, followed by a thorough watering. The plants will be ready to plant in their permanent location in late winter or early spring of the following year, ensure that you plant them in pre-moistened soil, but allow them to dry out completely before any subsequent waterings.
CultivationPinus sabiniana thrives in dry, sandy soils or gravelly loam and requires good drainage. This tree will do best if planted in an area with full sun exposure and heat. A suitable pH level for this species is mildly acidic to neutral. This tree does not cope well with salt exposure or compacted and heavy soils that stay moist for long periods; root rot is a common issue in these situations.
PestsA generally pest resistant tree. Pitch canker, western gall rust, armillaria, aphids, California five-spined engraver beetle, and verticillium wilt have been noted, although are not common. This tree is resistant to deer.
Notable SpecimensAs stated earlier, there is a Pinus sabiniana at an altitude of 2130 m at Sawtooth Peak in California. In addition to this specimen, the California Botanic Garden has a few specimens. They are located at 1500 N College Ave, Claremont, CA 91711, United States.
HabitatCommonly found in dry rocky slopes on mountains and in the foothill woodlands of California, it will grow in poor soils where other plants fail. Generally not found at sea level; instead it prefers elevations of 150 m to 1500 m, but also as high up as 2130 m at Sawtooth Peak.
Bark/Stem DescriptionOn old wood the bark of Pinus sabiniana is grey, new shoots will display a dull brown colour before fading to match the old growth. The trunk of the tree is deeply furrowed and scaled. Oftentimes the scaly ridges break away, revealing the dull brown colour of new growth which contrasts against the rest of the trunk. The roughness of the trunk is matched by the larger limbs, but slender limbs are smooth with pronounced lenticels.
Flower/Leaf Bud DescriptionThe buds form at the tips of branches in clusters and are ovoid and very resinous. The buds have an orange to red colour and their tips are sharply pointed. They are roughly 1 cm long and are heavily scaled, the scale margins have white fringes.
Leaf DescriptionLeaves develop in groups of three per fascicle and can be from 15 cm to 32 cm long. The leaves droop and twist slightly, giving the tree a wilted appearance. In colour they are an insignificant and dull green, however, they are tinged blue due to bloom. This bloom is different from the bloom you may have seen on the species Picea pungens in that it is much more waxy and reflective, and it forms around the stomata on the underside of the needles. The margins of the leaves are slightly serrate and the apex is accuminated. The fascicles are a warm brown and are about 2.5 cm long.
Flower DescriptionPinus sabiniana is a monecious species; the strobili appear in early spring. Male strobili are approximately 3 cm to 4 cm long and have a wide range of colouration when immature. They begin as either pale green or yellow and morph into a reddish-purple as they mature. At full maturity they are light brown. Female strobili are slightly smaller in size and also begin as pale green or yellow in immaturity, eventually changing to a reddish-purple and then finally a light brown when mature. Both strobili develop on short peduncles and rapidly grow in size until they are mature. It is interesting to note that once the cones fall off the peduncles often persist, giving the tree branches a very spurry appearance. The strobili of both genders curve slightly and have rounded scales.
Fruit DescriptionThe cones are large and rounded at maturity, among the heaviest of all North American Pines (about 0.3 kg to 0.7 kg). They can grow from 16.2 cm to 33 cm long with a diameter of 12.7 cm to 25.4 cm. Shape is ovoid and resembles that of an Ostrich egg. They are light brown in colour. The scales curl slightly at the tips. Cones begin developing in early spring, but are not fertilized until March or April; after pollination they mature in October and immediately disperse their seeds. The seeds are dispersed extremely slowly, sometimes not finishing until the following spring. Once relieved of seeds, cones may persist for several years. Cones are arranged on reflexed stalks, close to the branch. The seeds themselves are also quite large for a Pine, approximately 19 mm to 25 mm and weighing up to 1 g. It has been noted that the seeds are buoyant, and have been known to travel great distances by rivers. Seeds are ovoid with broad wings, dark brown in colour.
Colour DescriptionThe needles of Pinus sabiniana are a dull green. The glossy stomatal bloom that forms on their undersides gives it an attractive dark colour that is tinged slightly blue. This colour contrasts brilliantly with the light grey of older bark. The light browns of new growth, smaller branches, mature cones and the fascicles offer further contrast. Finally in the spring, the colouration of the strobili is a vibrant clash of light greens to purple against the more muted tones of the rest of the tree. Through the seasons, with the exception of the strobili and buds, the colour stays relatively the same.
Texture DescriptionThis is a coarse textured plant; the bark is heavily furrowed and flaky. The needles, despite being quite flexible, are pointed sharply, as are the buds. The immature cones are soft, but as the season progresses they become more rigid and spiky.

Photographs