September 13, 2007

Yard Probably Doesn’t Need Tilling, but Aerating


Q. In late August I treated my lawn with Roundup to kill the crabgrass and wiregrass so I can plant fescue. It apparently did a good job because everything is turning straw brown. A friend at work said I should till up the yard before I plant new seed, but that seems drastic to me. Do you think I need to till it or would running an aerator over it be good enough?

A. I think tilling is too drastic, also. If your existing top soil grew a good crop of weedy grasses, it will grow fescue. My recommendation is to rent a core aerator and make at least two passes across your lawn. The more holes you can make, the more reservoirs there will be to trap seed and fertilizer. Right after you finish running the aerator, broadcast your seed and your first application of fall fertilizer. With a little water or rain you should have green sprouts coming up in a week or two.

By the way, if you haven't had your soil tested lately, collect 20 or 30 of the plugs left on the surface by the aerator and mix them all together in a clean bucket. A pint of that mixture will give you an ideal sample of your soil to be tested.

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Q. I'm a lawn nut and have a pretty decent yard. However, I've found this weird variety of grass growing in clumps. If I pull it out, it comes up in clumps like sod, and it's very easy to pull up. The blades are finer than fescue and a shade or two lighter in color. I took a sample to a local turf supply company and they thought it was some kind of bluegrass. I started with good sod and every fall I overseed with certified fescue seed. Do you know what it is and how did it get in my lawn?

A. The grass you have sounds like Poa trivialis, which is a perennial bluegrass. I know you're aware of Poa annua, which is an annual bluegrass. Poa trivialis can be carried by birds, but it can also be found in seed mixes. Because it's a perennial bluegrass, it is not considered a weed on many seed labels. In fact, in some areas of the country it is planted as a turf grass. On a tall fescue label, it would be considered a "non-crop" species. Meaning it isn't a weed, but it's also not the crop on the label.

As you've noticed, weed killers don't touch it. Glyphosate is the only good control. You would want to treat it immediately so you could reseed in a week or two. I have seen a lot of it over the years, and it is getting more and more common. It really does stand out in a nice tall fescue lawn.

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Q. I have two large rhododendrons next to our house in Goochland County. They are on the south side and are shaded by mature oak trees. They clearly like this location, as each is about 9 feet tall and almost as wide. Unfortunately, they completely obscure a downstairs window and have to be moved. Is it possible to successfully transplant a mature rhododendron, and if so, when should it be done and what tips can you give me for success?

A. Rhododendrons 9 feet tall would be difficult to move on your own without killing them. These plants have a shallow-root system that is wide. I'm afraid if you try to move them yourself, you will lose them. If they absolutely have to be moved, you can only hope that some of the roots survive and the plants won't totally die.

If these plants are planted close to each other, so that the tops might be touching each other, the roots are probably totally entwined. That means you'll be damaging the roots of one while you try to dig up the other.

Several tree services and a few landscapers in the area have "tree spades" that can be used in certain conditions to dig up large root balls and move them successfully. I think it would be worth your time to get some bids on having them moved that way.


Gardening show: The next episode of "Virginia Home Grown" will

discuss farm-raised shrimp and residential irrigation.

Tune in: 8 p.m. Sept. 18 on

WCVE-Channel 23.

Send questions to Richard Nunnally in care of the Flair Department, Richmond Times-Dispatch, P.O. Box 85333, Richmond, VA 23293 or by e-mail to [email protected]


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