List of pH-Sensitive Plants

Trees

• A soil level of 6.5 provides the most nutrients, and most plants grow best in a pH range from 6.0 to 7.2. Trees that grow best in highly acidic soils with a pH of 5.0 or less include the American beech (Fagus grandifolia); flowering and Japanese dogwood (Cornus florida and kousa); loblolly and Virginia pines (Pinus taeda and virginiana); pin and willow oaks (Quercus palustris and phellos); river birch (Betula nigra); and sourwood (Oxydendrum arboretum).

  Trees for alkaline soils with a pH above 7.0 include the American and European hornbeams (Carpinus caroliniana and betulus); black maple (Acer nigra); gingko (Ginkgo biloba); northern and southern catalpa (Catlapa bignonioides and speciosa); redbud (Ceris canadensis); and Serbian spruce (Picea omorika).

Shrubs

• Highly alkaline or acidic soils often lack essential nutrients and micronutrients. Plants growing in such sites often develop iron deficiency, or chlorosis, in which foliage develops interveinal chlorosis, or yellow foliage with green veins. Very acidic sites often have toxic levels of manganese. Shrubs that tolerate a pH higher than 7.0 include cranberry and spreading cotoneaster (Cotoneaster spiculatus and divaricatus); glossy abelia (Abelia x grandiflora); Japanese and mentor barberry (Berberis thunbergii and x mentorensis); and rose of Sharon (Hibiscus syriacus).

  Shrubs for acidic sites with less than 5.0 pH include blueberries (Vaccinium spp.); bottlebrush buckeye (Aesculus parviflora); fothergillas (Fothergilla app.); mountain laurel (Kalmia latifolia); and rhododendrons and azaleas (Rhododendron spp.).

Ground Covers

• If your soil is alkaline, amend it with acidic organic matter such as peat, spaghum peat moss, elemental sulfur or acidifying fertilizers, or build raised beds to keep plants away from the alkaline soil. Ground covers that tolerate pH above 7.0 include barrenstrawberry (Waldsteinia fragarioides); skunkbush sumac (Rhus trilobata); snowberry (Symphoricarpos albus); and trefoil (Lotus corniculatus).

  Ground covers that need acidic soil include chokeberry (Aronia melanocarpa); heather (Calluna vulgaris); Korean barberry (Berberis koreana); sweetfern (Comptonia peregrina); wineleaf cinquefoil (Potentilla tridentate); and wintergreen (Gaultheria procumbens).

Perennials

• If your soil is highly acidic, amend it with high-pH materials such as calcitic limestone, composted manures, mountain peat or wood ash. Perennials that thrive in pH levels from 5.0 to 5.5 include bleeding heart (Dicentra spectabilis); gayfeather (Liatris spicata); Japanese iris (Iris tectorum); pussytoes (Antennaria dioica); and trailing arbutus (Epigaea repens).

  Perennials that need alkaline soil include bugleweed (Ajuga spp.); daylilies (Hemerocallis spp.); pinks (Dianthus alpinus); sages (Salvia spp.); sweet William (Dianthus barbatus); and wallflowers (Erysimum helveticum).