University of Illinois Extension

Tips for Roses, Trees and Houseplants

A few tips can make life easier for the summer gardener who deals with roses, trees, and what to do with houseplants while on vacation, said a University of Illinois Extension horticulture educator.

“For roses, avoid fertilizing after mid-August,” said Ron Wolford. “Fertilizing roses after mid-August can promote new growth that will not have time to harden off before the cold temperatures set in. After roses have gone dormant, you can fertilize and the fertilizer will be available to the plant in the spring.

Photo of black spots on a rose“Watch out for black spot on roses. Circular black spots appear on the leaves starting from the bottom of the plant and moving upward. Splashing from rain or watering will spread the disease. Spray weekly with a fungicide. Read and follow all label directions. The fungus causing black spot overwinters on fallen leaves, so raking and removing the leaves in the fall will provide some control.”

Watch for leaf drop and leaf scorch on trees in hot, dry weather, he said. Maple and ash trees are especially prone to dropping leaves when under stress from heat and drought.

Photo of scorching“Leaf scorching occurs when the leaf tissue turns brown and dies,” he said. “Scorching occurs on the leaf edges. Water is being lost from the tree faster than the tree can replace it. Watering trees during dry periods can reduce leaf drop and scorch.”

Going on vacation and wondering how to water your houseplants?

“Set up a temporary houseplant self-watering system in your bathtub,” said Wolford.

“All that is needed is an old dish-drying rack, white cotton shoelaces, and a bathroom that gets some natural light. Set the disk rack upside down in the tub and place the plants without saucers on the rack. Poke three to four inches of shoelace into the soil through the drainage hole. Run a few inches of water into the tub. The shoelace will act as a wick and keep your houseplants from drying out.”