Joel Hollingsworth wrote:
Paul, kayomuchi wrote that the St. Augustine grass had spread very quickly over the area the cedar had occupied, and the weeds were holding it back in an area very far from the cedar (opposite side of the house).
Point taken on the allelopathy of cedar (I had forgotten!), and of course about the N, but it sounds like those issues have not been a problem for the conditions and species we're being asked about.
I'm curious what the weeds are exactly, and what else is different between the two sites. My guess was that St. Augustine would normally struggle to get enough moisture in those parts, but the influence of the house, and some extremely deep soil, had helped it out in places. A further guess was that an enormous mass of mycorrhiza had lost its partner when the cedar was felled, and recently found some grass to live with instead, but further reading since my post yesterday suggests that this isn't as likely as I had supposed.
Interesting thoughts on the effects of cedar debris on weeds and on the St. Augustine, of course. As to your questions, the St. Augustine in the backyard is more sheltered than that in the front yard and I think that is the difference, and not the soil. Don't know what those weeds are but they look almost identical to the St. Augustine but grows in clumps and doesn't have the deep, deep green of St. Augustine. After last summer's struggle I can spot a single blade of that nightmare weed 6 feet away!
After I wrote the initial post last fall I simply fertilized with Ringer Lawn Restore and left it alone ... by late winter/ early spring I had a bumper crop of fall/winter weeds. It was truly horrifying. After deciding not to feel guilty I sprayed this mess with a product designed for St. Augustine and Centipede and watched the weeds melt away and discovered that every plug of St. Augustine had survived the winter and the established St. Augustine quickly greened. I bought a pallet of Centipede (it is more hardy than St. Augustine in this area) and filled in the areas that were formerly filled with weeds and used the rest to cover another area in the backyard where I had had another cedar tree cut down. In a matter of days the St. Augustine in the front yard began to send out runners like crazy and in another month my front lawn will be solid.
If the St. Augustine in the backyard is a reliable indicator, once the lawn becomes thick it won't need anymore weed killer ... got my fingers crossed. That being said, my neighbors on both sides both used to have strong, healthy St. Augustine lawns (I am told) but are letting them "go native," one out of laziness and the other out of old age. Is it possible to keep a lawn weed free naturally when almost every other lawn on the street is full of weeds?
