Cedar-apple rust is easy to spot but somewhat harder to control

By fall, the yellow spots on top of this apple leaf will develop black spore cases on the underside. The spores will be wind-blown to a nearby cedar and will grow to form an orange mass of jelly in a few years. (Walter Reeves for The Atlanta Journal-Constitution)

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By fall, the yellow spots on top of this apple leaf will develop black spore cases on the underside. The spores will be wind-blown to a nearby cedar and will grow to form an orange mass of jelly in a few years. (Walter Reeves for The Atlanta Journal-Constitution)

Q: I have two apple trees in my yard that have recently developed orange specks on the leaves and started dropping young apples. Chase Weber, Braselton

A: I’m confident you are seeing the signs of cedar-apple rust. This disease typically doesn’t cause major damage, but you should make an effort to limit its spread. Cedar-apple rust requires a nearby juniper plant to carry out its full life cycle. The common Eastern redcedar, Juniperus virginiana, is usually the second host of the disease. Look around your property and decide if you have any of these trees that can be removed. If they can’t be removed, watch for bright orange, gelatinous “blobs” on branch tips in April. These should definitely be removed before they dry out to resemble brown English walnuts on the branches. Rake and remove the leaves and fruit that drop from your trees. One online reference states that Red Delicious, Gala Supreme, McIntosh and Liberty apple varieties are considered resistant to cedar-apple rust, but Golden Delicious, Rome Beauty, and York Imperial are highly susceptible.

Q: I am using a mixture of vinegar and salt and detergent to kill weeds. Will it hurt the mature oak, magnolia or pine trees in my yard? Margaret Landry, email

A: Philippus Aureolus Theophrastus Bombastus von Hohenheim (known as Paracelsus by his friends) is considered by some as “the father of modern medicine.” One of Paracelsus’ key observations was that “The dose makes the poison.” In other words, a substance that is harmless in small amounts can be poisonous in large doses. Whether your trees will be hurt depends on how much of your concoction soaks into the soil. If you just spray it on the weed leaves, I don’t think there is any danger to the trees. In my experience, your mixture is not dangerous to most weeds either. Commercial herbicidal soap works better.

Q: Who keeps a list of big trees in Georgia? My dogwood tree is 35-40 feet tall. It has a 38-foot canopy spread, and the trunk is approximately 40 inches in circumference. It’s the biggest dogwood I have ever seen, and anyone who sees it says the same thing. Gabi Mattison, email

A: There are champion tree lists kept for Atlanta and for Georgia. I checked both and was surprised to find that four of the biggest flowering dogwoods in the state are within 10 miles of my home in north Decatur. They are scored using the traits you listed: height, crown spread and trunk circumference. I’ll let you figure out your tree’s score and follow the nomination process. I have all the details at bit.ly/GAchamptree.

Email Walter at georgiagardener@yahoo.com. Listen to his occasional garden comments on “Green and Growing with Ashley Frasca” Saturday mornings on 95.5 WSB. Visit his website, www.walterreeves.com, or join his Facebook Page at bit.ly/georgiagardener, for his latest tips.