Growing Grass Near Trees; the North and South of It

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Growing Grass Near Trees; the North and South of It

Q: My lawn was once immaculate, but then my wife and I planted several trees without understanding the damage the shade would do to the lawn. I now have more dirt and weeds than grass. And the grass keeps dying. I'm in the process of getting dirt delivered and having it spread, leveled and tapered for the natural flow of rain fall. My worry is how to keep the grass healthy with limited sun that after all that prep work…

----Tim in Hendersonville, Tennessee

A: From the mid-summer timing of this question, we presume that our listener has chosen to go with a cool-season grass, whose ideal planting time is mid-August through mid-September (although you could stretch it into late September in their area, which is just outside of Nashville). A warm-season grass would be installed in the Spring.

Oh—and if that 'dirt' hasn't been delivered yet, I suggest they stop to really inspect what they're buying; ideally you want compost or a high-quality screened topsoil that's rich and black in color when it's dry. The last thing you want to buy is a truckload of clay.

And we hope that they intend to plant one or more of the fine fescues. The most shade-tolerant of all the cool-season grasses, a fine fescue mix is the ideal choice for shady spots. IF the area gets at least four hours of sun a day; and if you're willing to water a lot during dry spells.

Yes, I have often said that shade loving grasses don't need a lot of water because they're not broiling in the sun, but in this case we have big bullies nearby whose roots are going to suck up all the water they want before any gets to the grass. People tend to realize the problems caused by shade, but they often fail to recognize that trees are also real water hogs. In situations like this, a lawn will often survive the lack of sun, but lose the battle for water to the roots of their trees.

Q: A landscape company is attempting to sell my elderly neighbor Fescue. She has a lawn almost identical to ours, facing west. But because of the tree canopy, some areas only get about an hour of sun a day in the Summer, and our Bermuda grass is slowly dying. Will Fescue survive any better after the trees leaf out?

---Helen in Oklahoma City

A: Well, again we have the same water issue. Although the OK state sometimes has to endure Biblical floods, Oklahoma can be mercilessly dry. And their legendary wind that "comes whipping down the plains" makes things worse, as it's constantly sucking moisture out of plants. But no matter what, I can say with confidence that Bermuda is the wrong grass here.

Bermuda is a very popular warm-season grass down South, but it's also a full sun grass that does very poorly in shade. It's also very thirsty; that's a double whammy under big trees.

Now: What to think of this fescue idea?

Oklahoma City is (like a good third of the US) in the Transition Zone, where you have to roll the dice and choose a cool-season or warm-season grass, knowing that neither one will look really good year round. (Definition of the Transition Zone: Too hot for cool-season grass and too cool for warm-season grass.)

If she can keep it well-watered, a blend of cool-season fescues might not mind the lack of sun in summer (its least favorite season); such a fescue lawn would be seeded sometime between Aug 15 and the end of September. The most shade tolerant warm-season grass is St. Augustine; it would perform much better here than Bermuda, and, like all warm-season grasses, would be installed in the Spring.

Q: Back in May, I had a new lawn installed by a local landscaper. The prior "lawn" (weeds, ivy and some daylilies that were relocated) was turned over and topsoil added, then graded, fertilized and seeded (primarily a fescue mix due to all the trees and accompanying shade). I have good grass growing on about 75% of the area, but weeds and crabgrass on the remainder. What's the best way to deal with this? I suspect that the landscaper will recommend a commercial weed and feed product, but I'd prefer an organic alternative.

---Howard in the New Jersey Pinelands

A: I have to thank Howard for this perfect opportunity to remind our listeners that THE organic 'weed and feed', corn gluten meal, prevents as many kinds of weeds when it's applied in mid-August as it does in the Spring. (Long-time listeners might remember my surprise when our lawn care guy Dr. Nick Christians from Iowa State told me that little fact; and then added that he had been trying to tell me for years!)

I'm Irish. Third times the charm.

Anyway, to quote Nick: "many broadleaf weed seeds germinate right after the summer heat stress period is over. Dandelion, clover and plantain are the main ones. Then the winter annuals like henbit and common chickweed usually germinate a little later." So an early fall feeding with corn gluten meal is a great start at preventing weeds next year.

Then you'd apply it again just as the forsythia and redbuds start blooming in the spring to stop new crabgrass from sprouting. Then all you need to do is cut a little bit higher than normal—three and a half inches instead of three to compensate a bit for the shade—and we should be off to the reasonable-looking lawn races.