Looking for suggestions for an existing (2 year old) foundation bed that is having problems with some of the spreader yews and encore azaleas in the bed. Most of the problem is probably related to having only fair drainage. May start moving things around in the fall. Variegated abelia is doing well. Most daylilies are ok. Just planted Catawba crepe myrtle. Some yew and azaleas are fine others have yellowing leaves. 1-2 hrs sun in part of bed, 3 hrs afternoon sun in all of the bed. About 250 sq ft. Have amended clay soil as I planted and have drip irrigation. However receiving advise that this can exacerbate the problems.
Would like to know how others work in these conditions and what they have found that succeeds.
How old is that foundation? The difficulty may be with lime leaching and creating too alkaline an environment. For best planting prospects the soil should be tested by your local extension service. No sense spending time and money amending soil when you don't know what's wrong with it.
Yews need a slightly acid to neutral soil pH. Azaleas and rhododendrons need an acid pH. Daylilies are cast iron but prefer a neutral to slightly alkaline pH. Here is a list of some plants and their pH preferences. http://homeharvest.com/flowersornamentalstreesshrubsphpreference.htm I am suspicious that your foundation is leaching lime. Rubble may have been backfilled against the foundation. This is a common way for builders to get rid of their construction garbage. The reason for being suspicious is because the abelia, which prefers a neutral to alkaline pH is doing well. Anything over a pH of 7 would be considered alkaline. Tennessee leans towards acid soils.