I planted a number of sunflower seeds in the front yard recently as an 'instant' plant to fill some of the space in the front yard, and they've been coming up really well in the areas where I shifted the soil significantly, such as the circles in the middle.
However, none of the sunflowers planted in the strip along the front of the house have sprouted, and I think it has something to do with the quality of the soil. Instead of taking the hint and mulching, I decided just to 'transplant' some of the sunflower plants from one of the circles to the bad soil strip.
One day after transplantation:
Lesson learned. Tomorrow I'm going to head to the nursery to pick up some mushroom compost for the front yard.