Acid Soil Plants

Lists of plants requiring acid soil have been published from time to time, but are often contradictory. Most plants grow equally well in neutral, mildly alkaline, or mildly acid soils, varying from 6 to 8 pH readings, or even 5 to 9. With these we are not now concerned. Real acid-soil plants prefer a soil that tests not over 6.5, and thrive best at a pH of 4 to 6. Acidity below pH4 is too extreme even for most acid-soil plants.

Plants which seem to need a decidedly acid soil include :

Andromeda	Flax	Lupine	Rhododendron
Azalea Lily	Galax	Magnolia	Sourwood
Baptisia	Ground-pine	Marigold	Sweet-fern
Bayberry	Heath	Mountain-laurel	Sweet Pepperbush
Blackberry	Heather	New-Jersey-tea	Spicebush
Blueberry	Hemlock Spruce	Oak	Spruce
Butterfly-weed	Hickory	Orchid	Swamp Ferns
Cardinal-flower	Huckleberry	Pieris	Trailing Arbutus
Chrysanthemum	Lady-slipper	Pine	Wintergreen
Cranberry	Leather-leaf	Platycodon	Yew
Dutchmans Breeches	Ledum	Radish
Fir	Leucothoe	Raspberry

Most extreme in their demand for acid soil, and most frequently injured by alkalinity, are plants of the Heath Family, especially Rhododendrons.

Injury often follows their use as foundation-planting material. House builders are likely to throw at the base of the wall and cover with earth pieces of lime, concrete, mortar, stucco and plaster, all of which are poisonous to acid-soil plants. Even evergreens of the Pine Family, most of which prefer mildly acid soil, are often harmed and even killed by such alkaline materials. Consequently, before planting any acid-soil plant near the foundation, dig out all filled earth and either reject it or screen it to remove the debris. If the wall is concrete, stucco, brick, or stone with mortared joints, the drip from it will cause the soil close by to become gradually alkaline. To prevent this, keep the planting well forward from the wall, use peat or leafmold frequently, and water often ; or strew aluminum-sulphate close to the wall.

Signs of alkaline poisoning in acid-soil plants are: drooping, yellowing and falling of leaves ; lack of root development ; poor health not otherwise explainable. If emergency measures are called for, water with a solution of 1 part commercial tannic acid to 50 parts water. Also never use lime, bonemeal or chemical fertilizers on acid-soil plants, except fertilizers known to contribute to acidity, as sulphate of potash, ferrous-sulphate or superphosphate. Even these should be used with caution.

Also See Acid Soil

Related Articles

• Acid Soil - ACID SOIL - In addition to exhibiting differences in texture (or physical condition) and in fertility, soils may be either acid, neutral or alkaline. The degree of acidity or alkalinity has an important bearing on the health of many plants. Acids and alkalis are opposite and if mixed together tend to neutralize each other, so that
• Acid Phosphate - ACID PHOSPHATE - A term sometimes used, but less than formerly, for the chief source of phosphoric acid in commercial fertilizers. Now called superphosphate, it is made by treating phosphate rock with sulphuric; however, it does not cause soil acidity as the term might suggest.