Plant Problems: Yellowed Leaves, Galls
Rain earlier this summer followed by drought and heat brought both problems and victories.
Brian Tabone’s citrus tree started yellowing along the edges. He fertilizes with a product specifically for citrus, following the label’s instructions. These symptoms are typical of nutrient leaching under waterlogged conditions, but to rule out any disease problems, we checked with Dr. Kevin Ong, in the Texas Plant Disease Diagnostic Lab.
Kevin confirmed that the plant appears to be staying too wet, maybe even constantly sitting in water. Waterlogged potting soil can become anaerobic, and if an organic fertilizer is being used, the method of nutrient breakdown may be microbial, which would be inhibited under anaerobic conditions. In this situation, the plant will not have access to any of the nutrients that are in the product. To combat this, remove the catch basin and allow the container to dry out, then apply some chelated iron, followed by your normal fertilizer regime, and be careful not to overwater moving forward.
In Cedar Park, Mindy Denney asked about her mom’s crape myrtle. While companion trees are doing fine, this one is turning orange and brown. To rule out disease, we again contacted Dr. Ong, who believes these symptoms are a sign of environmental stress, perhaps due to heat, or more likely some kind of root problem.
Doris Acevedo planted a one-gallon bur oak tree last October. It’s growing fast, but also showing damage on the leaves. It’s a little hard to tell from these pictures exactly what’s going on, but I think it’s most likely oak leaf blister.
Oak leaf blister is common in years when we have heavy rainfall, cooler temps, and cloudy days in spring, when the tender new leaves are emerging. Oak trees generally survive oak leaf blister will minimal long-term effects, but since this tree is so young, it may be set back a little further than it would be if it were more mature. At the end of the growing season, or maybe earlier, the tree will drop these infected leaves, which should be raked up and tossed out. If the environment is back to “normal” next spring, in other words warmer and drier in spring, the fungus shouldn’t be an issue, giving the tree time to recover.
So, what’s this plant in Jerald Lacey’s Cedar Park garden? He thought he planted chili pequin, but this plant has black berries. My Extension horticulture program assistant Sheryl Williams tagged this as Solanum nigrum, commonly known as black nightshade, which is a relative of chile pequin and other peppers, as well as tomatoes and potatoes. Although many of the plants in this family, the Solanaceae, are edible, many of them are not, and can be quite toxic. Luckily, black nightshade is not TOO toxic, but even still, this is a good reminder: never eat any part of a plant until you can positively confirm that it will not harm you.
During this increasingly hot, dry summer, viewers across Texas are making sure that butterflies and other pollinators are well fed. In Ropesville, butterflies head for Monica Rubalcaba’s zinnias.
Laura Fox collects zinnia seeds every fall to throw out in spring. She tells us that they “quickly and magically pop up through lantana, salvia, and Pride of Barbados.” Her flowers attract plenty of butterflies and bees every day, and bring joy to all her neighbors.
In San Antonio, Jimmie Hearn is feeding beneficial insects and hummingbirds with one of my favorites: Peter’s Purple beebalm.
A golden orb-weaver keeps guard over Brigitte and Steve Tannen’s lantana.
And have you ever seen a leafcutter bee in action? Here’s Jordyn Brewer’s quick video. The damage is temporary—the bees are simply gathering nesting material.
And Keith Hansen, former Extension Horticulture Agent and now consulting as East Texas Gardening, caught this great shot of a tiny wren nestled into an Amorphophallus leaf.