Answer: Azaleas require soil that is acidic, organic and humusy, and evenly moist yet well drained. Often, new concrete leaches lime and raises the soil pH so if they are going along the porch area you may want to reconsider where you are going to plant them -- this may not be acidic enough to keep them healthy.
Also, they will do best in a spot that is sheltered from winter winds and also protected from hot summer sun in the afternoon. A location in bright dapppled light all day or on the east side of your house would be best. A south or west exposure is not suitable due to excessive summer (and winter) sun.
To prepare the soil you should ideally run some basic soil tests to determine the pH and fertility levels, then modify as needed based on the test results. In most cases soil can benefit from the addition of some organic matter and also some coarse builders sand. Azaleas are very sensitive to poor drainage, so if you have a clay based soil you may need to plant them in a slightly raised bed to improve the drainage.
They should be planted no deeper than they grow in the container, possibly a half inch higher. Mulch with an acidic mulch such as pine bark year round. Apply the mulch in a flat layer about two inches deep. Water as needed to keep the soil evenly moist like a wrung out sponge. Azaleas are very sensitive to drying out because they are shallow rooted, so use your finger to test the soil and see when you need to water.
Before planting you will need to remove excess sand, rocks, and also the weed barrier as this would interfere with their rooting. The soil should be prepared so it is uniform or it will not drain consistently and this can cause problems later.
Your local county extension should be able to help you with the soil tests and interpreting the results with an eye on growing azaleas. They should also have information available on lawn repair and maintenance -- and the soil tests will help with that, also.
Since this is not the best time to be seeding lawn, you might try to seed the bare area now but plan on renovating or seeding the lawn grass again early this fall.
In the meantime, here is some information on lawn repair that you may find useful. You may need to cut and paste the complete url to make it work correctly.
I hope this helps.
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