Acidic soil is simply defined as soil that has a pH of less than 7. You can test your soil by using an inexpensive pH kit or taking a soil sample to your local Cooperative Extension Service. If you'd like to make your soil more acidic, mix a 1- to 2-inch layer of organic matter such as sphagnum peat into the soil. Gardening in acidic soil gives you the choice of a wide variety of striking plants that thrive in low-pH areas, producing their best foliage and blooms.
A native of the southeastern United States, Witch-alder (Fothergilla major) is a deciduous shrub that can reach heights of up to 10 feet. The plant boasts rich green, oval shaped leaves and fragrant bottle-brush flowers that have a smell similar to honey. Witch-alder will only grow in acidic, moist soils; it cannot tolerate lime. Witch-alder can grow in full sunlight or in partial shade, though it will do better in partial shade.
Rhododendron (Rhododendron spp.) is a tremendously popular plant found naturally almost everywhere in the world. There are more than 3,000 rhododendron cultivars. The woody shrub boasts large, floppy blooms in colors ranging from white to hot pink, purple and blood red. Though light requirements vary from full sun to shade depending on the variety, all rhododendrons require moist, acidic soil.
Hydrangea (Hydrangea macrophylla) is an unusual deciduous shrub that produces flowers depending on the pH of the soil. The shrub produces its most noteworthy blooms in acidic soil, exploding into color with deep blue flowers (as opposed to the greenish flowers from neutral soil or pink flowers from alkaline soil). Native to Japan and Korea, hydrangeas are cultivated for their ball-shaped flowers, which are often dried for bouquets. Hydrangeas grow best in moist, well-drained acidic soil in full sun or partial shade.