Juniperus Scopulorum "Blue Arrow" - Blue Arrow Juniper / Rocky Mountain Juniper

Height of seedling 10-30cm a   

   

As the name suggests, the Rocky Mountain juniper comes from the western parts of North America, the Rocky Mountains region and their surroundings. The distribution area reaches in a north-south direction from the southwestern parts of Canada through the United States to the state of Arizona and in some places to the northern parts of Mexico. It usually grows at an altitude of approx. 500–2700 m. Rocky mountain juniper is the western equivalent of juniper (Juniperus virginiana), as the differences between the species are small. They also cross with each other. Several varieties have been bred from the rocky mountain juniper. One of the most popular is the upright, blue-grey-leaved 'Blue Arrow' variety. It was first introduced to the market by Pine Grow Nurseries, in Pennsylvania, USA. It was apparently selected from among the naturally born seed seedlings of the 'Sky Rocket' variety in 1949. The variety is more upright compared to its parent and is gradually replacing it in Europe. Seen from a distance, the plant resembles the older ones in appearance, e.g. Mediterranean cypress (Cupressus sempervirens).

Rocky mountain juniper 'Blue Arrow' is a slow-growing small tree, the growth rate can be approx. 10–15 cm in length and 5 cm in width per year. It is one of the narrowest juniper varieties. In Finland, depending on the place of growth, it can become approx. 1.5-3 meters high and 0.5-0.8 m narrow, single-trunk, densely growing, upright branching and -growing, compact, small tree, the shoots of which are densely pressed vertically against the trunk. The bark of the tree is red-brown. Young shoots are blue-green in color. The plant's scale-like, evergreen, opposite thuja-like leaves are soft, pointed and silver-blue. They are 1-3 mm in size. long ones. When rubbed, they give off a strong, pungent smell.

Rocky mountain juniper 'Blue Arrow' is dioecious and blooms in late spring and early summer. The stamens are approx. 2-4 mm in size. The berry-like seed cones are approx. 5-8 mm in diameter. sizes. It takes about 18 months for them to mature. They turn silver-blue when they ripen.

Rocky mountain juniper 'Blue Arrow' thrives best in a sunny location. It tolerates a wide variety of soils in terms of nutrient content. It thrives best in slightly acidic soil. The soil must be fresh and permeable, as the plant does not tolerate standing water. An unsettled young seedling needs regular watering. The established rocky mountain juniper also tolerates dry periods. Rocky Mountain Juniper 'Blue Arrow' does not thrive in an urban environment; It does not thrive in very dense or saline soil. The plant does not need a shaping cut, as it develops a symmetrical columnar shape without cutting. However, diseased and dead branches should be removed from the plant. Even though the variety 'Blue Arrow' is rather slender, to prevent shape damage caused by heavy snow, at least in areas with heavy snow, it would be good to tie the tree's crown together for the winter. The plant should also be protected from the spring sun, e.g. by wrapping it in a shading net. In cold winters, the young shoots of the rocky mountain juniper 'Blue Arrow' can be damaged by frost. The variety is also suitable for growing in a pot. Although, it limits the size of the plant. As a potted plant, it needs ample watering every 7-10 days, depending on the weather. Rocky Mountain Juniper is unfortunately prone to some insect pests and fungal diseases. However, the variety 'Blue arrow' is said to be completely resistant to the Gymnosporangium fuscum fungus that causes pear rust on pear buds, which plagues the base species and several of its varieties.