I live in Houston Texas. I have a large Live Oak tree (about 16 years old with a drip line radius of 15 ft) ringed with dwarf-ish "Burford" Holly. I'm tired of the hollies jumping out an biting me and want replace them with a suitable (softer) shrub. I don't want to endanger the Live Oak with the shrub removal and subsequent replanting. What procedures should I follow?