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Is Your Cold Hardiness Map Useful?
Last week, we looked at the new U.S. Department of Agriculture hardiness zone map and the fact that it does not prove global warming. Using 30 years of one measure of weather to create a map for gardeners while ignoring all of the other weather …Read more.
Stop The Presses! The Headlines are Wrong!
Have you heard that the United States Department of Agriculture has released a new plant hardiness zone map for the United States? You may have heard that this map indicates global climate warming.
Does the new USDA map offer proof that the climate …Read more.
Transporting Trees: No Easy Feat But Well Worth the Effort
Q: I have nine dwarf fruit trees (including apple, peach, pear and plum). I will be moving this coming spring or early summer. These trees have been on my property from one to four years. Some have produced fruit, and some have not. Is it possible …Read more.
All-America Selections 2012 Award Winners
One way I've found to pick the best plants for my garden is to look at the All-America winners for the New Year. If it has been tested and approved in the All-America Selections (AAS) testing program, I can trust the plant to grow in my yard. Almost …Read more.
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Rust Diseases Can Harm Juniper and Rose Family PlantsQ: We have odd-looking growths on our juniper shrub. They are brown, woody and about the size of a golf ball. I thought the juniper's fruit were small little berries, but these almost look like a pine cone. A: Your juniper has a rust disease. There are three common rust diseases on junipers and red cedars, which spend half their life on that plant family and half on rose family plants. First, cedar-apple rust is caused by a fungus that attacks eastern red cedar (juniper) as well as a few other junipers. It then attacks crab apples and apples. In order to survive, the fungus must switch from one type of host to another. Cedar-quince rust is caused by a fungus that has eastern red cedars, common, prostrate, Rocky Mountain and Savin junipers as its evergreen hosts. This fungus has a wide range of rose family host plants, including apple, crab apple, flowering quince, hawthorn, mountain ash, quince and serviceberry. Cedar-hawthorn rust occurs on eastern red cedar, southern red cedar, Rocky Mountain juniper, prostrate junipers, apple, crab apple, hawthorns and sometimes pear, quince and serviceberry. On the evergreen host plants, the diseases affect small branches and needles. Usually, they kill the small branch, but some will stay alive for several years. They sometimes just cause small open wounds in the twigs that release the rust spores, but the large balls you are seeing are more common. When these galls are actively sending out spores to infect the rose family plants, they are awesome looking. Imagine a golf ball made out of orange marmalade that has dozens of 3-inch long tentacles hanging off of it — you are looking at a rust gall on a cedar tree. This active growth stage occurs in wet weather and the same gall can grow tentacles several times. On the rose family plants, the rust affects leaves, branches and fruit.
The fungus spores on junipers go to the rose family plants and the fungus spores growing on the rose family plants go to the junipers. The spores can be carried several miles, but they are very infectious when they only have to travel a few feet. I have seen entire landscapes made from the plants in these two families: junipers and roses. Junipers come in tall tree shapes, wide-spreading shrubs and low ground covers. Look at the above list of rose family plants and you will see plenty of commonly planted trees and shrubs. The juniper fungal spores are released in the spring when the rose family plants are starting to grow new leaves. The disease may take a few months or a year to develop in the rose family plant. The spores from that plant go back to the juniper family in summer and fall where the disease grows the following spring, summer and fall. The life cycle of these rust diseases can take two years. Your plants may be infected with more than one of the diseases at any one time. Once the plant is infected, you can't stop the disease for the time being. You can cut off the galls as you find them. Most plants are not harmed enough to try fungicides, but severely infected plants may benefit. There are a few resistant plants available, such as some hawthorns. This is mostly a group of cosmetic diseases, but they can defoliate a rose family plant. Fungicides labeled for rust could help them. The juniper family rarely has large infestations. E-mail questions to Jeff Rugg, University of Illinois Extension at jrugg@illinois.edu. To find out more about Jeff Rugg and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com. COPYRIGHT 2010 CREATORS.COM 
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