Bartlett Tree Experts: Juniper

Juniperus spp

The Juniperus genus consists of between 60 and 70 species, native to the northern hemisphere from the Arctic to tropical Africa. They are considered one of the most resilient plants to high altitudes known to grow as high as 16,000 feet in Tibet and can live many years. The berries are used as a spice in a wide variety of culinary dishes as well as the spirit gin. The Dutch word for juniper, genever, is where the spirit gin gets its name. Icelandic folklore dictates that boats should be built with both Juniper and Rowan wood or neither, using only one will make the boat sink.

Culture
Concerns
Management

Culture for Juniper

Juniper is a small tree. Some species are trailing (prostrate). The bark is brown to grey and peels with age. Twigs may be reddish brown. Leaves can be very sharp and prickly. They thrive in positions with well drained soil and high light levels. They will tolerate light shading, however, too much shade will cause a change in growth shape. They are highly tolerant of salt spray and pollution making them excellent street trees/shrubs. pH preference is between 5 and 6.

Concerns about Juniper

Junipers are susceptible to Phytophthora root rot, tip mining insects, and fungal diseases such as Phomopsis blight and rust. Pear rust is dependent on Junipers to complete its lifecycle causing canker like swellings year round on juniper branches, in spring these sprout horn shaped orange yellow fruiting bodies. These become gelatinous when wet.

Management Practices for Juniper

Check roots for

Phytophthora

root rot. Ensure suitable soil drainage is present. If tip dieback occurs, inspect for tip mining insects or evidence of

Phomopsis

blight. Canker like swellings can be pruned out however, they are unlikely to cause significant damage to Junipers but may cause significant damage to Pears.