Question
Over spray from weed and grass killer has left large dead grass areas. Now that Fall is coming what should I do?  Dig up the dead grass now and plant seed and fertilizer or wait until the Spring to repair the damage? I live in Northern Illinois.

Should I transplant a mum bush now before it blooms fully? Two mum bushes were planted too close together last year.  

Answer
Good afternoon Jayne:

The site below is one of the best ones for northern Illinois. Some of what I am about to tell you comes from that site.

http://www.urbanext.uiuc.edu/lawntalk/

It sounds as if you are in need of lawn renovation.  I would strongly consider killing all the weeds and what remaining grass you have by an application of  glyphosate (Round Up). Make sure you follow directions on the label.  If you have shaded areas consider bark mulch or ground cover only in those areas instead of grass.
Think of renovation as fitting one of three levels: overseeding with little additional work; significant work, but allowing existing grass to remain; or completely removing the existing lawn and starting over. The decision of which level to choose is based on how bad the lawn looks and what caused the problem.
One of the first steps in successful preventive programs is to seed or sod a properly adapted turfgrass species in the lawn. Following establishment, adequate fertilization programs and cultural practices facilitating the maintenance of a dense canopy including proper mowing practices, good watering practices, and insect and disease control programs are important.
If you choose to re-seed or sod thoroughly work the soil to a depth of 6 inches. Add amendments such as compost, rotted manure, organic topsoil, peat, etc.
After your grass is up and growing cut it to a height of 2 ?to 3 inches. Cut it frequently and remove no more than 1/3 of the grass blade at each mowing. Water it to provide one inch of water per week when needed. Water in the morning hours not in the evening or at night as that will spread diseases.
Weed control after renovation involves control of annual and perennial weeds.
Annual grass weeds are grass weeds that germinate from seed, grow vegetatively, produce seed and die within a 12 month period. A number of annual grass weeds routinely invade turfgrass areas including crabgrass, goosegrass, foxtail, barnyardgrass, fall pancium and annual bluegrass. The crabgrasses are the most common annual grass weeds in most lawns. Both the smooth and hairy types of crabgrass are classified as summer annual weeds.  These annual grass weeds are usually lighter green in color, have wider leaf blades and possess more spreading growth habits than the cultured cool season turfgrasses.To ensure crabgrass and other annual grass weeds do not establish in home lawns, both important preventive and control programs must be implemented. The invasion of crabgrass and other annual grass weeds can be prevented to a large degree by maintaining a dense, healthy stand of grass. A high quality lawn will develop a highly competitive canopy which will shade the soil surface and discourage the germination and establishment of seedling annual grass weeds. Most annual grass weed seeds germinate in the top 1/2 inch of the soil.
The crabgrass seeds in the soil begin to germinate in the spring once the soil temperatures warm to nighttime minimum temperatures of 52 to 54 degrees F for at least 5 consecutive nights under conditions of moist soils.
For homeowners who cannot satisfactorily address the control of annual grass weeds in a preventive manner with strictly cultural controls, the best way to stop annual grass weeds from establishing in their lawns is through the use of preemergent herbicides. Preemergent herbicides are chemicals that prevent the germinating weeds from establishing in the lawn.  Lawns with thin stands of grass that do not provide 100 percent cover may require yearly applications of a preemergent herbicide to prevent the invasion of crabgrass and other annual grass weeds.
Preemergent herbicides are generally only effective if applied before the annual grass weeds emerge. Therefore, early spring applications are essential if satisfactory weed control is to be achieved.  Herbicide applications should be completed and the herbicide watered-in at least 7 days prior to the initial germination date to allow time for the herbicide barrier to be established in the soil.
Perennial grassy weeds are considered to be the most difficult weed problems to deal with in lawns. Control options are limited because the weed species are very similar to the lawn species. For example, several common perennial grasses, when growing in Kentucky bluegrass lawns, are considered weeds because they differ greatly in leaf width, color, or growth habit. Tall fescue is more coarse and grows in distinctive clumps when it occurs with Kentucky bluegrass. Creeping bentgrass, a very desirable turf species for golf courses, becomes a weed in bluegrass lawns because it appears as patches of finer grass, usually lighter in color. Zoysiagrass, a warm season turf species, appears as patches of thick grass, dormant (straw-colored) for much of spring and fall in Kentucky bluegrass or other cool-season grass lawns.
There are additional perennial grasses that are frequent weed problems. Quackgrass, a coarse species with thick underground stems (rhizomes) can be a major problem in lawns. Nimblewill, a creeping warm season species, often appears as light colored patches in lawns.
One way to distinguish perennial grasses from annuals is the time of the year established plants are present. Perennials (other than nimblewill and zoysiagrass) will appear as established green grasses early in spring; whereas most annual grasses like crabgrass don't appear until late spring or early summer. Likewise, most annuals die off quickly in fall, but perennials do not.
Selective chemical control is not an option with most perennial grassy weed species. Unlike selective herbicides used on annual grasses, nonselective herbicides used to control perennial weed grasses may also damage the lawn species. For this reason, spraying over the lawn is not suggested unless the problem is severe enough that all grasses need to be killed and the lawn reestablished. Using a nonselective herbicide, such as glyphosate, patches of the undesirable species can be spot treated. After weeds and portions of lawn die, reseed with desirable grass species. Treating in mid-August is generally thought of as the best timing (late July to early August to control nimblewill and zoysiagrass), as late August into early September is the most favorable time for reseeding. If resodding the area afterwards, there is a longer period of time to treat the weeds. Keep in mind the weed species needs to be actively growing to be controlled by glyphosate, however. Allow 10 to 14 days to determine if weeds have been completely controlled.
I hope I haven't given you so much information that you become discouraged. Once you get that great looking lawn it will be well worth all the initial work and expense.

Oh yes, the mum. I would leave it until next spring and divide it when you get antsy to get that garden soil under your finger nails.

Good Luck!

Floyd McMahon