We've had the weeds on our backyard hill removed. The hillside is now bare but still has the roots of the cut weeds. Do I need to treat the area before laying a weed blocking fabric and then planting a ground cover. I'm concerned that without treating the ground/hill, weeds will shoot through weed blocking material with the upcoming winter rains.
You are correct to be concerned about the unwanted vegetation returning when the rainy season begins.
It would have been advisable to spray the seasonal grasses and weeds first before they turn brown to kill out the roots.
Your other concern is the weed seeds produced before the vegetation died out. The hillside is now covered with dormant seeds waiting for moisture to germinate.
Spraying the vegetation while it was still green would have prevented the production of seeds. But it's too late to do anything about that now. So, I'd now use mulch as your primary method of controlling weeds and seeds.
You would lay the fabric down, plant the ground cover, and then cover the open area with a thick three-inch layer of mulch. This should be sufficient to eliminate the light from reaching the ground and stymie the growth. Landscape fabric and mulch is a short-term answer for weed prevention.
Over time the mulch breaks down into smaller and then tiny particles. It then becomes an ideal soil for the undesirable vegetation seeds to grow in. Every year we have a new flush of seasonal weeds and grasses, and the seeds from this growth are then blown everywhere. The unwanted growth is now growing on top of the landscape fabric.
Controlling the weeds become more complicated because of the desirable plants. You can apply a pre-emergent herbicide such as Impede from Monterey Lawn and Garden right over the top of rooted plants without harming them to kill the seeds. Impede puts down a chemical barrier that prevents the seeds from germinating. This will only be viable if the hillside is under irrigation other than drip irrigation.
You need moisture to set up the barrier; otherwise, you have to wait and time your application to just before a significant rain of the season in late October or November. This should control most of the unwanted vegetation, and it's repeated annually.
I'm removing the stump of a dead tree, but I don't want to grind it. Are there any 'do it yourself' tree stump removal products? Also, is it possible to plant a lemon in this area?
Stump removal products are available at your favorite garden center. They use Potassium Nitrate to dehydrate the stump by speeding up the dry rot. Their biggest drawback is time as they take several months to work.
There is no reason to be concerned about planting a lemon tree where the tree once grew. How you remove the stump will have no impact on the growth of any citrus varieties. Personally, I would grind the stump, as it is the fastest and quickest way to get rid of it.