Rhododendron × 'Red Quest' (Rhododendron 'Red Quest') is a compact evergreen shrub grown for its showy clusters of purple-red flowers and year-round, medium-green foliage. You will get the best color and healthiest leaves when you site it in part shade, especially with protection from hot afternoon sun and drying winter winds.
Plant in consistently moist, well-drained, acidic soil rich in organic matter. Work in composted pine bark or leaf mold at planting time, and keep a 2-3 inch layer of mulch over the root zone to help conserve moisture and keep roots cool. Water deeply during dry spells, particularly the first season, but avoid soggy soils.
At maturity it typically stays in the 24-36 inch tall range with a similar spread, making it a good fit for woodland borders, foundation plantings, and mixed shrub beds. Give it room for air movement, and avoid burying the crown when mulching.
Maintenance is simple: prune only as needed to shape or to remove winter-damaged stems, and do it right after flowering to avoid removing next year's buds. If you deadhead spent clusters, do so carefully to protect the new growth just below the blooms.