Here are this week’s gardening questions and answers, provided by Parker County Master Gardeners. To submit a question, send it to firstname.lastname@example.org. For more information about Parker County Master Gardeners, or to become a member, call 817-598-6096 or visit www.pcmg-texas.org.
I had a pear tree with fire blight and have chosen to remove it. Can I replace it with another pear tree, or should I plant something else?
I suggest you plant something else. It isn’t wise to put another plant that is susceptible to the disease in the same spot. Fire blight is a bacterial disease that affects apple trees, pear trees and roses. If rainfall occurs during bloom, there is a good chance that fire blight will be a problem. Bees carry the bacteria from bloom to bloom, and this spreads it throughout the plant.
There are no effective chemical controls, but pruning out the cankers will help stop the spread. Cuts need to be made 6-8 inches below the visible sign of infection on the stem. After pruning, clean the pruners with a 10 percent bleach solution followed by a light application of oil to kill bacteria and prevent rust. The varieties kieffer, orient, Garber and Douglas are old varieties of pear that have some resistance to the disease, but may still be affected.
Special thanks to Dr. Jerral Johnson, professor emeritus, Plant Pathology and Microbiology, Texas A&M University
How do I care for iris after they have bloomed?
When blooms are spent the bloom stalk can be cut back, but leave the blades standing. This will continue the process of food production for the plant, which will be stored in the rhizome for next year’s growth. When the bloom cycle is complete, the leaf blades add a significant background element in your beds. You may want to trim off any browning edges, but leaving the rest of the leaf blade will be a benefit for the plant.
Later in the summer, you may choose to cut the blades in a fan shape no shorter than five to six inches. It does not take them long to produce new growth and add green color to your landscape. When you add mulch to the bed, be sure that the rhizomes are not buried. These should remain at the surface of the soil and have some exposure to the air.
I have verbena and was told to deadhead it. Why should I do this?
The goal of most flowers is to reproduce by growing seeds within the spent flowers. Deadheading is the practice of removing spent blooms from the plant before the seed forms. Removing old blooms will cause many plants to quickly bud and bloom again in order to reproduce before the season is over. The practice of deadheading will give you a longer season of color in the bed. This is true for many flowering plants.