Many commonly used landscape plants are calcifuges, preferring soils with a pH below 7.0. Since each full numerical decrease in the pH value represents a ten-fold increase in acidity, a decrease in pH from 7.0 to 6.0 represents a ten-fold increase in the acidity of the soil. Nutrient availabilities vary considerably with varying pH. The availably of Iron (Fe), Manganese (Mn) and Magnesium (Mg) are typically heightened in lower pH soils; therefore chlorosis is common on acid loving plants when grown in high pH or alkaline soils. To increase your soil's acidity, pH (lower alkalinity) you may use sulfur, iron sulfate, sucrated iron, aluminum sulfate, compost, bark mulches, conifer needles and most any other humus. Remember, when watering with our very hard, alkaline tap water, we continuously add lime to the soils. So, it is important to locate plants that require acidic soils and consistent moisture near downspouts or in low lying areas so our natural acidic rainfall will help keep the area acidic. Never mulch any of the following plants with gravels containing limestone or alkaline components. If using gravels, one of the best is crushed granite.

The following list is not an endorsement of these plants for use in the landscapes. Some are bona fide weeds. In our Autumn 2003 newsletter we listed plants that prefer or tolerate high pH or alkaline soils. The following list shows plants that prefer neutral to acidic soils. * Preferring slightly acidic to neutral soils. ** Preferring acid soils but adaptable to slightly alkaline soils. These often show chlorosis on high pH or alkaline soils.
Soils may be tested at the Soil & Plant Analysis Lab, 5711 Mineral Point Rd. 608-262-4364, near Cuna Inc.

Abelia mosanensis Korean Abelia

Abies balsamea Balsam Fir

A. concolor White Fir

A. fraseri Fraser Fir

A. koreana Korean Fir

Acer circinatum Oregon Vine M.

A. ginnala Amur Maple **

A. japonicum Fullmoon Maple

A. miyabei Miyabe Maple

A. palmatum Japanese Maple

A. pseudosieboldianum Purplebloom M.

A. rubrum Red Maple**

A. saccharum Sugar Maple **

A. sieboldianum Siebold Maple

A. tegmentosum Manchustriped M.

A. triflorum Three-flower M.

Aesculus glabra Ohio Buckeye

A. flava Yellow Buckeye

A. parviflora Bottlebrush B.**

Alnus glutinosa Black Alder **

Amelanchier arborea Downy Serviceberry

A. canadensis Shadblow S.

A. laevis Allegheny S.

A. stolonifera Running S.

Andromeda polifolia Bog-Rosemary

Acrtostaphylos uva-urs i Bearberry

Betula alleghaniensis Yellow Birch

Betula lenta Sweet Birch

B. nigra River Birch

B. papyrifera Paper Birch**

Calluna vulgaris Scotch Heather

Carpinus caroliniana American Hornbeam**

C. japonica Japanese H.

Chamaecyparis spp. Falsecypress

Chionanthus virginicus White Fringetree**

C. retusus Chinese F.

Clethra alnifolia Summersweet

Comptonia peregrine Sweetfern

Cornus alternifolia Pagoda Dogwood**

C. canadensis Bunchberry

C. florida Flowering D.

C. kousa Kousa Dogwood

Corylopsis glabescens Fragrant Winterhazel

Daphne cneorum Rose Daphne*

D. x burkwoodii Burkwood D.*

Disanthus cercidifolius Disanthus

Enkianthus campanulatus Redvein Enkianthus

Erica carnea Heath

Fagus grandifolia American Beech

F. sylvatica European B.*

Fothergilla spp Fothergilla

Gaultheria procumbens Wintergreen

Halesia tetraptera Carolina Silverbell*

Heptacodium miconioides Seven-son Flower

Hydrangea macrophylla Bigleaf Hydrangea

Ilex glabra Inkberry

I. verticillata Winterberry

Kalmia latifolia Mountain Laurel

Larix spp Larch Tamarack

Magnolia acuminata Cucumbertree*

M. x soulangeana Saucer Magnolia

M. x loeberni Loebner M.*

M. stellata Star M.

Mahonia aquifolium Oregon Grapeholly**

Metaswquoia glyptostroboides Dawn Redwood

Microbiota decussate Microbiota

Myrica pensylvanica Northern Bayberry

Nemopanthus mucronatu Mt. Holly

Nyssa sylvatica Black Tupelo

Ostrya virginiana Ironwood*

Oxydendrum arboretum Sourwood

Pachysandra procumbens Allegheny Spurge*

P. terminalis Japanese S.

Parrotia persica Persian Parrotia**

Picea abies Norway Spruce*

Pieris japonica Japanese Pieris

Pinus banksiana Jack Pine

P. cembra Swiss Stone P.*

P. densiflora Japanese Red P.*

P. resinosa Red P. **

P. rigida Pitch Pine

P. strobus White Pine**

P. sylvestris Scotch P.

Prunus subhirtella Higan Cherry

Pseudolarix amabilis Golden-larch

Pseudotsuga menziesii Douglas Fir*

Pterostyrax hispida Fragrant Epaulettetree

Quercus alba White Oak

Q. bicolor Swamp White Oak

Q. imbricaria Shingle Oak

Q. palustris Pin Oak

Q. rubra Red Oak*

Q. velutina Black Oak

Rhododendron spp Rhodendron

(Except R. prinophyllum )

Rhus aromatica Fragrant Sumac

Salix yezo-alpina Yezo Willow

Sassafras albidum Sassafras

Sciadopitys verticillata Umbrella Pine

Sorbus aucupaira European Mountainash

S. americana American M.

Spiraea albiflora Japanese White

Stewartia spp Stewartia

Styrax spp Snowbell

Tamarix spp Tamarix

Taxodium spp Baldcypress

Tsuga canadensis Canadian Hemlock

T. caroliniana Carolina Hemlock

T. diversifolia Japanese Hemlock

Vaccinium spp Blueberry & Cranberry

Viburnum x burkwood Burkwood Viburnum*

originally published 2004 V18 #1

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