We have a juniper (in Boulder, Colorado) that developed this Gymnosporangium rust disease or fungus. This is a problem in BC and elsewhere in the West as well. The literature and forum research (including UBC Botanical Garden - search for "sick juniper") I have found describes the problem, but does not give clear and definitive solution as to how to treat affected trees AND how to prevent the "rust" from spreading to nearby junipers. From Colorado State Extension: "1450 Juniper-hawthorn rust Juniper-hawthorn rust is a fungal disease that requires a juniper and an alternate host to complete its lifecycle. Alternate hosts are apple, crabapple, hawthorn and mountain ash. On a juniper, two-inch ball-shaped galls develop on stems from spores blown in from the alternate host. A gall is an abnormal growth of plant tissues caused by the stimulus of a disease or insect. In the springtime, toothpaste-like spores erupt from these galls. Each mass is called a teliohorn. Spores from teliohorns are blown to an alternate host where they cause leaf spot. These spots are small, bright orange-yellow, and surrounded by a red halo. Spores are produced on the underside of each leaf spot in hair-like projections. Wind carries the disease back to junipers. Spores produced on a juniper only infect the alternate host, and spores produced on the alternate host only infect a juniper. Although the galls are innocuous to the juniper, repeated infection on the alternate host can cause early defoliation, and smaller fruit. Defoliated trees may suffer winter injury and often fail to grow fruit the following season. Cultural controls include removing juniper galls before they produce spores and separating junipers from potential alternate hosts. A few hundred yards separation is generally sufficient for practical Garden purposes. The danger markedly decreases with distance, especially when separated by a windbreak. Fungicides such as Bayleton and Daconil 2787 applied to alternate hosts at seven-to-ten day intervals, beginning at bloom, are effective. Chemical control is not necessary on a juniper except for aesthetic purposes. For more information, see the following Colorado State Extension fact sheet(s)." Our sick juniper is healthy on 2/3 of the bottom, but the top 1/3 is drying out and looks like will need to be pruned. That is where the gooey balls are. Would extra watering help the tree? What about another nearby juniper - not yet affected - what can I do as preventative measure? Thanks for any ideas.
Thank you for the suggestion. I have tried to remove the affected branches, but there are too many. The Colorado State article says that chemical methods are not available for junipers. The bottom line is that the tree will look deformed and scraggly; not what we want between our dining room patio door and the street. This juniper is similar to native plants that grow wild near our home. They also generally assume strange shapes as they mature (our juniper is about 10 years old).
If you don't have the time and patience to prune out the galls and spraying is not an option then it sounds like you are left with removal and replacement of the tree with something else.
jimmyq may be right. The tree (and it is a tree now) is situated on a slope. Water runs off and the plant may just not be getting enough water. We have had a very dry fall. Luckily, it snowed (about 20 cm) yesterday. I will keep an eye on this juniper. I do not want to lose it.
