Fall is a busy time in the landscape and the garden, and many questions were asked at the extension office as the gardeners worked in the yard.
Many people have noticed how much honeydew there is on sidewalks, cars and the street. Aphids feed on tree sap and leave sticky honeydew behind, but this can be avoided by applying a systemic insecticide like imidacloprid. It is best to do this in the spring and will last all season; so late in the year it is not necessary or very useful to treat, and the trees are unlikely to be significantly damaged.
Many homeowners have also asked about galls in trees, mainly oaks. Galls are abnormal growths on leaves and twigs caused by insects. Most galls and gall-forming insects are not harmful to plant health and their control is not warranted.
Invasive weeds of current concern include KR barbon and kakiweed. The barbon KR is an invasive perennial grass very prolific in some landscapes as well as in pastures. It is very difficult to control because it is a perennial and there are no selective herbicides labeled for it.
A preemergence herbicide will help prevent new plants from coming out of the seed, but will not kill existing plants. Keep the lawn dense and healthy, mow at the right height frequently, and fertilize appropriately – KR barbon is not very competitive and mostly appears in bare areas or stressed lawns.
Khakiweed grows flat on the ground and produces a lot of sharp strawberries that spread easily. It is also a perennial; Post-emergence herbicides that contain a combination of 2,4-D with mecoprop, carfentrazone, dicamba or metsulfuron (eg, the brand Fertilome Weed Free Zone) are effective in controlling existing plants. Keep this in mind next year and catch the plants early, as the herbicide will not be effective against large, mature plants. For now, use gloved hands or a garden hoe to physically remove them.
Fall is a good time of year to cover St. Augustine lawns with sphagnum peat moss, one to two bales per thousand square feet, to prevent root rot fungal disease. The acidity of the peat will help lower the pH and make it less hospitable to the pathogen.
October is a wonderful time to plant! This is the best season to establish trees, shrubs, ground covers, etc. Plant spring bulbs and wildflower seeds. Enhance the curb appeal with a cool-season annual color and keep the vegetable garden productive with winter veggies like broccoli, kale, lettuce, and beets.
Herbs like parsley and cilantro prefer cooler weather and do well in the fall. Dig and divide spring-flowering perennials like irises and daylilies – this will keep them healthy and blooming, and provide an opportunity to share with friends and neighbors.
Allison Watkins is the Texas A&M AgriLife Extension Agent for Horticulture in Tom Green County. Contact her at [email protected]