Here are some of the questions master gardeners fielded on their hotline this week. They answer questions from 9 a.m. to noon and 1 to 4 p.m. weekdays at 316-660-0190.
How do you control borers in a 10-year-old Austree?
An Austree is a fast-growing, temporary/short-lived tree that is usually dying by age 10. Borers are just finishing off a short-lived tree. Treating for borers will not significantly increase the life of the tree. Select longer-lived species from a reputable nursery to replace the Austrees when they die.
What is the easiest way to correct iron chlorosis (yellowing leaves) in pin oaks?
The quickest method is to have an arborist inject the tree with iron sulfate. By lowering the pH in the entire rooting zone, this will release the iron that is naturally high in our soils and make it available to the tree. For long-term results, start using an acidifying lawn fertilizer that contains sulfur each time that you fertilize the lawn, until the tree greens up.
What disease is causing the edges of all new tree leaves to turn black?
This is wind injury. It is especially common in exposed sites. The symptoms are shredded new leaves with blackened edges.
What is the rapid-growing stalk coming up through the middle of a rhubarb plant?
This is the flower stalk. To keep the plant healthy, just snap or cut out this bolting stalk to keep the plant producing leaves vs. producing flowers.