Gardening This Weekend: September 7, 2023

There’s going to come a time when a cold front will bring rain and cooler weather, and your fall gardening activities will have to pop into action.

With that in mind…
Let’s declare this the weekend that we apply pre-emergent weedkiller granules to prevent germination of Poa annua (annual bluegrass), rescuegrass and ryegrass. They will germinate as soon as soil temperatures begin to cool.

Apply Dimension, Halts or Balan granules to stop the growth of their weed seedlings. Once they’re up and growing there is nothing you can do to stop them. Those materials are safe on any type of lawn, even around trees and shrubs, but they must be applied immediately.

Make your fall application this weekend if you’ve not done so already. Follow your application with a moderate watering to coat the soil surface with the product.

We now return to our regular announcements…

Fall-blooming and fall-foliage annuals from quart and gallon containers for patio and entryway color this fall. Look for zinnias, marigolds, celosias, angelonias, purple fountaingrass, crotons and a host of other great plants for color now.
Mums, Mexican mint marigolds, Mexican bush salvias, Gregg’s mistflower and other fall-flowering perennials as you find them offered for sale in local nurseries.
Bluebonnets (acid-scarified seeds) and other spring-flowering wildflower seeds into gently prepared garden soil. Keep them moist to get them off to a good start.

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Perennial gardens to remove spent flowers and their stalks, seedheads and dried foliage. Keep things tidy. Mulch with shredded trees leaves as you mow your lawn this fall.
Johnsongrass, grassburs, dalligrass, KR bluestem and other weed grasses frequently to remove seedheads. Also ragweed to remove sources of pollen. (Do not confuse ragweed with its inconspicuous green flowers with the non-allergic goldenrod with its lovely yellow blooms.)
Continue mowing lawn regularly to keep grass low and vigorous.

Water-soluble, high-nitrogen food to annual flowers and patio containers for a burst of new growth in fall’s better weather.
Use same water-soluble, high-nitrogen food with newly planted color annuals.
Turf with all-nitrogen food with significant percentage of that nitrogen in slow-release (encapsulated or coated) form. Turf experts tell us this fall feeding is critical. If you’ve been waiting to fertilize your St. Augustine due to gray leaf spot fungus problems in the hot weather, you should be safe to apply fertilizer now.
You’re running out of time to apply iron to chlorotic shrubs and vines such as wisterias, azaleas, loropetalums, and gardenias. If you have these or other shrubs with yellowed leaves with dark green veins displayed most prominently at the ends of the branches, apply an iron supplement with sulfur included. Keep iron off masonry and painted surfaces to prevent staining.

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Patio pots and hanging baskets for insects they may be harboring in their pots, potting soil or on their leaves. Before bringing them indoors for the winter spray all pests on the leaves outdoors in a shaded location. As for the soil-borne pests, put the pots in a tub of water and soak them for a period of time. That should drive them up into the water where you can dispose of them. You can also mix an insecticide at spraying strength, pour it through the potting soil, wait 10 or 15 minutes, then flush the soil with plain water thoroughly to get rid of the insecticide. Obviously, this is a task for a shaded spot outdoors.
Be alert to stinging caterpillars such as puss caterpillars (“asps”), Hagg moth and Io moth larvae and others as you work in your shrubs and taller flowers. This is the time of year they are most active. Watch for yellowjackets in hidden spots of eaves and snakes in piles of leaves.

Posted by Neil Sperry
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