How should I remove a patch of the wrong type of grass from my lawn?

Question

In the foreground of the picture, you can see a brown region. This is a different type of grass than the buffalo that makes up the remainder of the lawn.

I would like the whole lawn to be buffalo for a consistent look. How can I achieve this?

This small area of different grass has persisted for a number of years. It looks brown now as there has not been any rain for about 10 days. When it rains, it will come back green again.

The buffalo seems to grow better in summer, while the other grass grows better when it is colder. It's spring here now so I thought it might be a good time to address this.

Can I spray this with round-up, and allow the buffalo to grow in from the edges. Do I need to physically dig it up?

Edit: I dug up the patch. About 15cm down I hit cement. The soil was quite compacted clay.

It's not clear to me what this was. Might have been an old path across the yard

Answer 1

Buffalo grass is what is known as a warm season grass. It's well adapted to warm weather, it thrives when it's hot and tolerates drought very well, which is why it keeps looking green and healthy. The patch of other grass is some variety of cool season grass. They don't handle drought as well, preferring moister, cooler whether, hence why it looks better in early Spring, and right after it rains.

A cautious application of Round-Up will kill the grass, but you will want to do it when the grass is green. When it's brown like it is now it's entering dormancy, and Round-Up (and most herbicides) only works on plants that are actively growing.

However, we have to ask one important question: Why hasn't Buffalo grass over-taken this other patch already? Buffalo grass spreads by stolons (above ground runners) and if the cool-season grass looks this brown this early in the year it shouldn't be healthy enough to have kept out the Buffalo for this many years. The fact that the Buffalo grass hasn't colonized the area yet suggests that something about that particular patch of lawn is unsuitable for Buffalo grass. A soil test from the brown patch and another from the Buffalo grass might tell the story. Is there any reason to think that particular patch was subjected to more traffic? Or cut shorter than the rest of the lawn? Anything that makes that patch different from the last lawn might be keeping the Buffalo grass from being able to move in effectively.

Answer 2

No no...do not use Roundup. If this patch always looks like this until after a rain there is something just below the surface. Oh, I just saw your reply to Gardener J...a palette of tiles, huh? How long did this palette stay there? Might have killed the grass from lack of sun/water. If so, I'd just dig up this patch, make sure the soil level is as high as the rest of the lawn, COMPACT it and check it again and then reseed with THE SAME SEED MIX you've used before. Try not cutting so short for awhile. When you fertilize, fertilize the entire lawn AST.

Answer 3

Given the persistence (7+ years) of the problem area, I'd strongly consider cutting it out (and put into the compost), and (depending how you want to do this, and with what speed) either cutting sods from (many small spots) elsewhere in the lawn to fill it in (refilling those with good dirt and letting the lawn repopulate them) or purchasing sod of the correct type to fill in without cutting any from elsewhere in the lawn.