Fall Lawn Care Tips
Lawns in southeastern North Carolina are suited to warm season turf grasses such as St. Augustine, zoysia, Bermuda and centipede. Caring for warm season turf grasses can be very different from caring for turf grasses grown in cooler climates. As warm season lawns get ready to transition into the dormant winter season, there are some important things that should be done, and others that should not be done, to keep lawns healthy.
Do NOT Fertilize!
Grasses should only be fertilized with nitrogen when they are actively growing. For warm season grasses this is during the spring and summer, not fall or winter. Fertilizing warm season lawns in fall or winter wastes fertilizer, encourages weed growth, and can intensify disease problems like large patch. In the cooler parts of North Carolina and the United States, cool season grasses such as fescue and Kentucky bluegrass are grown. Cool season grasses do grow during the fall and early spring, and require fertilization at these times. Commercials and ads about fertilizing lawns in fall are referring to cool season grasses only.
Do NOT Water!
Warm season lawns should not be irrigated after early September. Fall is the time when warm season lawns are shutting down for winter. Continuing to irrigate lawns during fall can increase cold injury during winter and encourage disease problems. The only exception to this would be if we were experiencing a fall drought, which is certainly not the case this year.
DO Control Weeds
Just as there are warm and cool season grasses, there are also warm and cool season weeds. Cool season weeds come up in the fall, live through winter, then flower and die in the spring. Most cool season weeds are annuals, coming up each year from seed, but a few are perennials. Cool season perennial weeds come back from year to year from roots that persist in the soil. Two of the most troublesome, Florida betony and wild onion, have started sprouting in yards over the past few weeks.
Like most perennial weeds, it is very difficult to control Florida betony or wild onion by digging them up. Repeated mowing can weaken these weeds but will not kill them. The only way to really get rid of most perennial weeds is to spray them with herbicides, but one application will not do the job. Instead it takes repeated sprays over a couple of seasons. To begin controlling Florida betony or wild onion in your lawn, spray them now and again in February.
Which herbicide to use depends on your lawn type. In zoysia and Bermuda lawns, wild onion and Florida betony can be controlled with herbicides containing a combination of the active ingredients 2,4-D, mecoprop and dicamba. Brand names for these products include Weed-B-Gone, Lesco Three Way, and Speed Zone Southern. These herbicides will also control many of the common cool season annual weeds that are coming up in lawns now, including chickweed, cudweed, and spurweed.
Centipede and St. Augustine lawns are sensitive to 2,4-D. In these lawns instead apply Image, active ingredient Imazaquin, to control wild onions, and atrazine to control Florida betony. Atrazine is sold as Purge II, Aatrex, and HiYield Atrazine. In addition to controlling Florida betony, atrazine will also control many cool season annuals weeds. Please note: Brand names are included in this article as a convenience to the reader and do not imply endorsement by N.C. State University nor discrimination against similar products or services not mentioned.
For the long term, the most effective way to control weeds in turf is to nurture a healthy, dense lawn by following correct cultural practices. These include mowing at the correct height, having any insect or disease problems correctly diagnosed before treating, sending soil samples to the N.C. Department of Agriculture to determine your nutrient or lime needs, and following turf care recommendations for your lawn type available on the NCSU TurfFiles website, http://www.turffiles.ncsu.edu (click on the Maintenance Calendar tab).
For further advise on lawn weed control, contact your local Extension office. If you live in Pender County, call 259-1235. In New Hanover County, call 798-7660. In Brunswick County call 253-2610, or visit http://www.ces.ncsu.edu/where you can post your questions to be answered via the Ask an Expert widget. Visit the Pender Gardener blogto stay up to date with all the latest gardening news: http://pendergardener.blogspot.com/.
Charlotte Glen is a Horticulture Agent with Pender County Cooperative Extension of NC State University, College of Agriculture & Life Sciences. She can be reached via e-mail at Charlotte_Glen@ncsu.edu.