Diseases of Pacific Blue Junipers

The Pacific Blue Juniper (Juniperus conferta 'Pacific Blue') is a groundcover plant that grows 12 to 18 inches tall and spreads 6 to 8 feet wide. The ocean or blue green fine-textured needles are evergreen. Although junipers grow in a wide range of environmental conditions, they prefer full sun and well-drained soil. Pacific Blue Junipers are susceptible to several common fungal diseases that affect junipers.

The Kabatina juniperi causes tip blight on Pacific Blue Junipers. The symptoms appear only in late winter to early spring and affect 2 to 6 inches of the ends of the infected branches. Initially the needles turn dull green, and then turn yellow or red. Small silver or ash-gray lesions containing black fungal spores develop on the discolored plant tissue. In the summer, the needles turn brown and drop prematurely. Kabatina tip blight does not cause extensive dieback or death.

Another fungus, Phomopsis juniperovora, causes tip blight on succulent new growth on the last 4 to 6 inches of infected branches of Pacific Blue Junipers. The disease does not affect older foliage. Symptoms are more common in the spring and fall but also develop in the summer.

Infected needles turn dull red or brown and then fade to ash gray. Small gray lesions with black fungal spores girdle the tips of infected branches. Repeated incidences of blighting can cause witches broom (abnormal bunched growth), stunted growth or death of the affected plant.

Root rot caused by Phytophthora fungus is a destructive disease that leads to the decline and death of infected Pacific Blue Junipers. The needles of infected junipers are off-color, usually yellow. The plant grows slowly and some limbs wilt or die. The roots grow brittle and turn brown or reddish-brown, and the discoloration can spread up to the root collar of the plants. Heavy irrigation or rainfall, periodic flooding or poorly drained soils increases the incidence of Phytophthora Root Rot.