Iowa’s lawns have several weeds that are a basic nuisance when it comes to have a nice lawn. Crabgrass (Digitaria sanguilanis), Creeping Charile (Glechoma hederacea), Dandelions (Taraxacum officinale), Quackgrass (Agropyron repens) and Sandburs (Cenchrus pauciflorus). Each cause their own separate problems in the yard and they are very difficult to eliminate.
The best Crabgrass (Digitaria sanguilanis) killer is one that is a pre-emergent herbicide. This means that they herbicide needs to be put onto the ground in late winter or early spring. It works by killing the seedlings from growing. The soil temperature should stabilize at 55 degrees with a grass depth of 4 inches. The blooming of the forsythia should coincide with the killing of Crabgrass.
Creeping Charlie (Glechoma hederacea) is a weed that thrives in lawns in area where the grass is not thick and plus. The best solution for removal of Creeping Charlie is to seed your yarn with more grass seed. This includes seeding each area with the correct type of either sunny or shady seed. The plusher the grass, the less Creeping Charlie will be seen.
Dandelions (Taraxacum officinale) are notorious for growing back even when they have been pulled. The problem with Dandelions is killing the leaves will not kill the root. The roots are very strong and grow back easily. The best solution, even though it is hard work, is to dig down and remove the top of the Dandelion along with part of the root. Pour a small amount of weed killer (specifically for Dandelions) in the hole and cover it up. The weed killer will suffocate and kill the root. It will not grow back. Again, seeding the lawn and having a plus grass base will prevent the Dandelions from growing. Mow them off before they go into seed to prevent any seedlings from germination.
Quackgrass (Agropyron repens) grows in areas where no grass has germinated. Any small patch of dirt is the growing place for Quackgrass. Seed your lawn to eliminate any areas where yard grass isn’t growing. Pre-emergence herbicides work for Quackgrass. The seeds germinate in soil that has a temperature of 55 to 60 degrees so apply the pre-emergence herbicide in late fall or early spring. If done in the spring remember to wait a full 30 days before planting any new grass seed.
Sandburs (Cenchrus pauciflorus) may be eliminated by adding lime to the soil. By adding lime, the pH of the soil will be made more alkaline. The same may be true with the addition of magnesium or calcium. Have the soil tested before applying any of the chemicals to make sure the lawn is not burnt. Again, Sandburs grow where there is no grass. Seed your yard with the proper sunny or shady seed to achieve a plush yard.
Yard weeds are hard to eliminate and detract from a well-kept yards appearance. The biggest key to keeping down or eliminating the weeds within a yard is to have a thick plus grass covering. Seeding the yard to achieve this as a final goal takes two to three years. Keep this in mind both at the beginning and end of the growing season.