The next two weeks are perhaps the most pivotal time of the entire gardening year. You’d think that would be a statement reserved for some time in the spring, but it’s actually now. I offer tasks from the top of the list as my proof.• Apply pre-emergent granules sometime during the first 10 days of September. Weeds that will plague your winter and early-spring lawn are set to germinate and start growing any time now. All it will take to trigger the process will be a little cool weather and a shower or two. If you’ve been bothered by weeds like annual bluegrass ( Poa annua), rescuegrass or ryegrass (all grasses), or clover, chickweed, dandelions or henbit (all broadleafed weeds), apply pre-emergent granules the first week of September.
For grassy weeds, apply Halts or Dimension. For broadleafed weeds, apply a Gallery product. Remember, if you wait long enough that these weeds have started to sprout, you will have waited too long. You only get one chance on this. Your local nurseryman can assist you.• Finish all plantings of new Bermuda, St. Augustine or zoysia. These grasses are typically winter-hardy in our area, but new grass can be damaged by winter’s cold if it’s planted too late. St. Augustine sod and Bermuda seed need to be planted by mid-September. Zoysia and Bermuda sod should be down by the end of September.
• Keep your eyes peeled for late-season chinch bug damage to St. Augustine. It will always be in the hottest, sunniest part of your yard. The grass will appear dry, but it won’t respond to watering. You can even see the adult chinch bugs if you part the grass at the outer edge of an affected area.
Look for BB-size black insects with irregular white diamonds on their wings. Apply Imidacloprid to stop them. Their season will be over by mid-September, but they can do so much damage that you don’t want to try to wait them out.• Last call for applying Sedgehammer to control nutsedge in your lawn. It’s already past the deadline for the first of two applications of the Image nutsedge-control product. These are materials that are applied carefully according to label directions directly to the lawn, then watered in deeply. They must be taken in through the weeds’ roots, which is why you must apply them while it’s still warm.
• Root-prune wisterias that have failed to bloom in past springs. If you have a plant that is in full sun and isn’t exposed to undue amounts of nitrogen in the fall, root-pruning might make a difference. Use a sharpshooter spade to cut all the lateral roots 18 inches out from the trunk. Cut a slit (not a trench) 6 or 8 inches deep in the soil. The shock of having lateral roots cut often triggers the flowering process.
• Root-prune established trees and shrubs that you intend to transplant this winter. This is similar to what you would do to wisterias that haven’t bloomed properly, except in this case, you want to make the vertical cuts through the root system at the spot at which you’ll be making the final cut when you dig the plant while it’s dormant. Root-pruning gives it time to grow more active feeder roots before it actually will have to have them by next springtime.
• Apply all-nitrogen fertilizer to any warm-season lawn grass. Turf experts will tell you that this feeding is the most important one you will give your grass during the entire year. It will strengthen the grass before winter, and it will be stored in reserve for earlier spring green-up. This application should be made by mid-September, or by the end of the month at the latest.
• Plant all leafy and root crops for fall, including spinach, leaf lettuce, radishes, beets, turnips and carrots. This is a task that must be completed in the next 10 or 12 days to give them ample time to grow and mature before the first cold spells of late fall.
• Sow bluebonnet seeds into lightly tilled soil. Do not plant where lawn grass will compete with them in the spring. This actually applies to all spring wildflowers. They must be planted now so they can germinate and start establishing deep roots before winter.
• If you have daffodil or other spring-flowering bulbs you’ve been intending to dig and divide, early September is the time to do so — before they start their new season’s root growth.
• Webworms may appear in pecans, walnuts, persimmons and other trees in your landscape in the next several weeks. Spraying is pretty much futile, but you can usually reach most of them with a long-handled pole pruner. Simply nip out the twigs or small branches that are infested with the pests, then discard the webs and the worms that are in them. Be careful to keep clear distance from power lines as you prune.