(This is a sampling of the most important garden tasks for September. For a complete list, please see our annual Texas Gardening Calendar. Click here for information on our current special offer on the 2011 Calendar.)

Plant: Finish planting warm-season turf, including St. Augustine, bermuda by mid-month in North Texas, late month in South Texas. Sow rye for overseeding, or fescue for permanent turf, middle of month. Trees, shrubs. They will become well-established before next summer's stresses. Daylilies, iris, Shasta daisies, coneflowers, oxalis, violets, gloriosa daisies and other spring perennials can be dug and divided during September.

Prune: Remove dead or damaged limbs from trees, shrubs. If you're in doubt about the job, contact a certified arborist. Remove errant growth of shrubs and vines with light re-shaping. Do not prune spring-flowering shrubs and vines until after next spring's bloom. Root-prune native plants and established landscape plants which you intend to move in winter, to promote better root growth. Continue mowing lawn at recommended height all fall. Tall grass loses vigor quickly, so keep turf low and compact.

Fertilize: Apply quality all-nitrogen (for clay soils) or high-nitrogen (for sandy soils) ratio plant food with half or more of its nitrogen in slow-release form to turf, landscape and garden plants. This is the most important feeding of the year. In alkaline-soil areas, apply iron/sulfur material to correct chlorosis of wisterias, hollies, dogwoods, azaleas, Carolina jessamine and other acid-loving plants.

On the Lookout: See special story this issue on critical timing of pre-emergent weedkillers this month. Apply either Team or Dimension for winter grassy weeds and Gallery to prevent germination of broadleafed winter weeds. You must treat between September 5 and 15. Use glyphosate-type herbicide to eliminate all existing grass and weeds in areas you intend to develop this fall or next spring as cultivated beds. Application must be made several weeks before first killing freeze. Trim fall webworms out of pecans, walnuts, persimmons and other susceptible trees. Resume black spot fungicidal sprays for roses on 7- to 10-day intervals. Next time, consider the black spot-resistant EarthKind® roses. Brown patch will cause areas of St. Augustine to turn brown almost overnight. Blades will separate easily from runners, and you'll see decayed portions at bases of blades. Apply labeled turf fungicide.