I was thinking sprinkle some soil on late in the season and let the grass grow up through it the following spring I've done that before, except I did it in the summer. And did it several times. A little each time, so little that it didn't completely cover the existing grass. Let it settle in, and the grass grow out, enough that you only saw grass, and did it again.

real hard to give an answer... w/o a pic ... dead wood... is dead wood.. it will not resprout.. if that need be said ... then.. all you would be left with... is whether.. the hole is small enough.. for surrounding material to fill the space ... and the final variable.. is HOW LONG ... odds are very high that it will fill in ... the issue is.. HOW LONG ... are you prepared if it takes 5 years ... do not think this ill happen like it might with a shrub or a perennial ... in one season .... conifers are trees.. and they do things in TREE YEARS ... and if you can understand and accept that.. you will be pleased ... but if you think it will happen fast ... it better be a very small space ... you dont mention size ... i dont know how hard i would work.. to move big specimens... on something i might be able to mail order for rather cheap ... but that equation is all about how much exercise you want or need .. let see that pic you promised... and.. good luck ken ps: softball sized hole.. maybe in one year .. basketball ... 2 or 3 ... etc ...

Funny thing about that Mimosa-my folks had lived in Fort Myers for twenty years when, upon visiting them, I pointed out this neat, puffy-looking flower growing in the turf on some hell-strip by a mall. They had never seen it! I saw it my first day down there! I guess it's safe to say, the world is composed of two types of people, those who notice plants and those who don't. To wit, if you'll allow me to take this slightly further OT- a botany professor who writes a good blog was writing about his first-day students. He would show them a photo of some scene in a forest somewhere, tropical or otherwise, and ask them to write down what they saw in the picture. Almost to a student, if there was some kind of animal in the picture, it got written down. Nobody....not one student....took note of all the plant life in the photo! And this was a botany class. Sheesh..........I don't hold out a lot of hope for our future. In any case, sunshine mimosa is one of those subtropical plants that, when I'm down in FL I like to look at and conjure up the dream of using it in the north here as an annual. Not saying that would work, or that I'm going to be doing it, but just that it always makes me think about doing so. +oM

I was going to ask what kind of grass you have, but you answered that. Again, for future reference, we will almost always need to know where you live and what kind of grass you have. You did not mention how long you are watering. Once a week is right, but you have a apply a full inch. My sprinkler system takes 8 hours to deliver an inch, so you were likely not watering long enough. The way to check your system is to put out some tuna or cat food cans and turn on the sprinklers. Time how long it takes to fill all the cans. That is your watering time from now on. If you get runoff before the cans fill, then stop and let the water soak in for 15-30 minutes. Then restart watering and the stopwatch. My problem with the professional lawn care givers is they have a blanket approach to everyone's lawn. You may not need herbicide but everyone else does, so they will apply one for you. You can time the chemicals easily once you know what the timing is. March (or when the forsythia bloom) - apply preemergent April - spot spray broadleaf weeds IF NEEDED May - Memorial Day - apply fertilizer Sept - Labor Day - apply fertilizer Sept - late - spot spray for broadleaf weeds IF NEEDED November - late - fertilizer Watering is seasonal. When the temps are in the 90s, water once a week. When temps are in the 60s or below, water once a month. In between adjust to once every 2 and 3 weeks as the temp falls.