Hi brandyray, I have not treated anything yet. I talked to two local companies before last summer and went around and around with them. I had a contract with the first and they kept blowing me off about when they could come do the treatment. Months went by as I waited for them to be available. I finally called another company I had talked with initially and same thing, not even a call back from the actual arborist I'd met with. It's unbelievable! I guess these people don't care about paying business? They both came out and did an evaluation (for free) but would never show up to do the real work which would have actually earned them some money. I guess they are so busy they just don't care. In any case, it got so hot that I was afraid to try to use an oil on the smaller shrubs .. and the scale seemed to not be as bad on the big tree (I know it's still there .. just maybe not in it's active season?) so I never did do anything. I know they need to be treated, though. My plan is that now, in the next week or two, I am going to treat everything (the magnolia and the shrubs) myself using Bayer Tree and Shrub as suggested by ken_adrian. I am also going to spray all the smaller things I can reach with an organic neem oil. In fact, I just picked up the neem oil last night. I'm sorry I'm not more help. I will post an update after doing the treatments myself. Good luck with treating your magnolia. If you try spraying it yourself, will you let me know how it goes? Thanks.

Thatch is a build-up of organic matter which can include, dead grass leaves, stems, stolons, rhizomes, and overcrowded grass roots and lateral weed growth (Wikipedia). I can live with that definition. Key is build-up. You have one layer of fallen over dead grass. I don't think that meets the definition. I guess when I rake up the leaves I'm dethatching. Have you tried raking up the dead grass? The reason not to use a mechanical dethatcher is it is abusive to the turf. If you have stolons it will chop them into pieces. For St Augustine that can kill the plant. Zoysia is mostly spread with rhizomes, so you would not see it, but with a rake you can be a lot more selective as to how much of a beating the turf gets.

Aw, geez! Well, I need more information. Where do you live? Are you in downtown SD? Are you in La Jolla (where Marathon should work fine)? Or are you in El Cajon (where Marathon should not be used in a drought)? San Diego isn't all that big but the people who claim to be living there cover a wide area of climate and soils. Fescue is generally thought to be a 'cool season' grass. That means it's grown in the upper midwest and in the east but north of Georgia. It is more successful the farther north you get. Coastal California should be an okay place for fescue. But it is totally a luxury grass for interior Cali and to the east. I've seen it growing in Palm Desert and Indio, but what a mistake! (I've grew up in the Inland Empire but also lived in Pomona, Hawthorne, Downey, Huntington Beach, Palm Desert, Indio, Temecula, Hemet, Winchester, and Stanton. We had friends who lived in several places in the SD area, so I took some mental notes). You're not going to like my watering advice, but it will work almost no matter where you live. First you need more info about your own system. How much water does your system put out in 10 minutes? You can test that by putting cat food or tuna cans in the yard and measuring the amount you collect. Ultimately what you want to know is how long your system takes to fill those cans. My oscillator sprinkler takes 8 full hours to fill the cans. My neighbor's high flow system fills them in 20 minutes. You can't just guess at this. Okay so the watering mantra is 'deep and infrequent.' Deep means 1 inch (1 can) of water all at one time. It's the 'infrequent' part you're not going to like. Infrequent means once per week when the temps are in the 90s (La Mesa and to the east). When the temps are in the 80s (most of the SD metropolitan area), water once every 2 weeks. When temps are in the 70s (La Jolla and within the beach influence), water once every 3 weeks. I realize you have millions of Californians telling you that you need to water every day, but that is incorrect. And when I say incorrect, I'm talking about after reading thousands of messages in lawn care forums over the past 13 years. A friend of mine in Phoenix waters his St Augustine lawn once per week with temps of 115. Surely you can water less than 2x per week in SD. But before you jump into deep and infrequent watering, let's get some answers first. So, where are you? Also what are your specific watering restrictions? In San Antonio during normal times we're allowed to water 8 hours per day, but only once per week. During harder drought it's 7 hours per day and only once every 2 weeks. Every community is different, so what are your restrictions?

The first sentence of that site says it all. Semi-arid, few natural trees, IRRIGATION NECESSARY. So lets fight nature and do something that will require great expense and use a finite, precious resource, generally unavailable locally, for the next, oh 500 years or so. Because that's what scientists say is likely, a mega drought in the SW. It has happened in the past, probably several times, and will happen again, we may be seeing the beginnings of it now. Sometimes I wonder if 'Homo' is using the 'sapiens' of his namesake. Living in a "green state", what would I do for my well established trees, and I have a small forest, in the event of a severe drought? The same as I would do in any other natural event such as a forest fire, hurricane, flood, ice storm, or lava flow: absolutely nothing. Let nature take its course, survival of the fittest. Unless Planet Earth gets sanitized by a neutron star or some such event, trees will survive. Maybe not MY trees, but some trees. Or seeds. Somewhere. Young, newly planted trees are another matter, sometimes. If I am able, and depending on the species, they'll get watered for the first year, second at most, and only enough to keep them alive until the rain returns. In 2007, I lost a lot of newly planted stuff to the Easter freeze, and later pretty much everything else to the scorching heat and drought. Watering was futile, so I didn't even try. It was REAL hard for me to watch. Some of the large trees in the area still bear the scars of that double whammy. That year marked a turning point for me, I stopped actively planting my place.