| General Description | Juniperus californica is a dioecious, drought resistant, typically multistemmed, rounded shrub like tree native to California, slightly extending into Nevada, Arizona, and Mexico. This Juniper is common in the interior desert of California, where it grows slowly and does not reach a substantial height. Seedlings are shade dependent, often growing under mature trees, replacing them as they die out. Mature California Junipers require full sun to partial shade. An important tree in it’s ecosystem, it provides food and shelter for wildlife, as well as erosion control. J. californica’s growth period is between 340 – 360 days, but due to its slow growth it grows between 1 mm and 10 cm in a year. The size and growth rate of this tree greatly depends on the amount of water available. Typically reaches heights of 1 – 4.5 m, however specimens have been found growing up to 10 m. |
| ID Characteristic | Has small 6 – 13 mm, blueish, reddish waxy berry like cones containing typically 1 one seed, although at times 2 or 3. Multi stemmed, twisted, and turned branches reaching upwards and forming a round crown. Trunk has thin grey exfoliating bark; young limbs are smooth. |
| Shape | A moderately dense, broad, multi stemmed tree or shrub. Trunk and branches are typically irregularly shaped. Branches are typically erect, reaching upwards. Crown is rounded and open. |
| Landscape | California Juniper has a high value as an ornamental plant. It can be used as a hedge, informal screen or specimen plant. If used as a specimen or accent plant, it is important to give J. californica room to grow as they are typically wide trees that deter undergrowth. This tree also has high value in habitat restoration, and is used in sloped areas to prevent erosion. |
| Propagation | J. californica is a dioecious species; if propagating from seeds a male and a female tree is needed to produce viable seeds. Seeds should be collected when they turn ripe, towards the end of summer into autumn. They should then be extracted from the fruit and thoroughly cleaned and dried. Seeds should be stored dry at -6oC – 4oC. Seeds have a low rate of germination. A large quantity of seeds should be planted to increase rate of success. Soak seeds in warm water for 6 hours. Stratify at 5oC for 30 – 120 days. Sow seeds 6 mm deep in soil. Propagation from cuttings is possible, although some patience is needed as they can take up to 12 months to properly root. |
| Cultivation | A drought tolerant tree, J. californica needs protection from the sun as a seedling, once it is grown past 30 cm it needs full sun, with minimal shade. Although tolerant of a wide range of soil, it does require well drained soil and prefers coarse, rock, sandy or silty soil and does not tolerate moist soil well. Once established the J. californica requires little to no care. |
| Pests | Susceptible to root rot, rust, aphids, spider mites, beetle borers, armillaria. Also susceptible to Juniper Mistletoe, a parasitic plant that grows on the stems of Junipers taking water from the tree. |
| Notable Specimens | A large specimen is registered on California Big Tree, measuring 44 ft tall, located in West Pinnacles, California, United States of America. Other notable specimens are Santa Barbara Botanic Garden, Santa Barbara, California, United States of America, and Native Seed Network, Corvallis, Oregon, United States of America. |
| Habitat | Desert slopes below 750 – 1,600 m, dry alkaline soil. Needs moist, mild winters and dry, hot summers. An understory tree in climax forests of coastal foothills. Grows scattered in grasslands, and desert slopes. It occurs in Joshua tree woodlands. It also grows in communities associated with blue oaks, goldenweed, cliffrose, and birchleaf mountain-mahogany. While J. califonica only occurs in a small area
of North America, it has adapted well and is a part of many ecosystems within its geographical range. |
| Bark/Stem Description | Trunk is multi stemmed and typically irregularly shaped; rarely single stemmed. Mature bark is ash grey, thin and exfoliating in thin strips. Young branches are smooth and reddish brown, turning grey and exfoliating as they mature. |
| Flower/Leaf Bud Description | Staminate flowers occur from January to March. Flowers are 3 – 6 mm, typically in groups of 3 with 18 – 24 stamens with short rhomboidal anther scales. Pistillate flowers are typically in groupings of 6, ovate, small and nearly unnoticeable on berries. Leaf buds are small, stout and a light green-yellow. |
| Leaf Description | Leaves on young seedlings are 5 – 10 mm long and needle like. Adult leaves are scale-like and rather small at 1 – 2 mm long and 1 – 1.5 mm wide. Leaves are decussate, pitted on the back, bluntly pointed, margins are denticulate. Leaves are in pairs of 2 or 3 in an opposite or whorled arrangement. Shoots are 1 – 2 mm in diameter. |
| Fruit Description | J. californica is typically a dioecious plant. Female berries cones or berries are globose, sometimes oblong, waxy, blueish, reddish, brown in colour and contain 1 or 2 seeds and are 6 – 13 mm in size. Female berries take 9 months to mature. Male berries, or cones, are 2 – 4 mm and release pollen from March to May. This tree is anemophilous. |
| Colour Description | Foliage is a light green to dark green with a blue tinge. Bark is a light grey colour. New growth is a green yellow colour, and turns red-brown into its third year. As branches start to mature, the leaves fall and turn grey and the bark begins to shed, turning from smooth to exfoliating. The berry-like cones have a white waxy bloom and are blueish, turning a reddish brownish colour in their second year. |
| Texture Description | Foliage is finely textured. Trunk is coarse. |