Lime hating plants

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There is a group of plants that resent having high levels of lime (chalk, calcium) in the soil. If lime is present they are prevented from absorbing the full range of nutrients, in particular iron, which they require for good healthy growth.

They may survive for a short period, even up to several years, but they rarely produce new growth and the leaves decrease in size and turn yellow (chlorosis). Strangely they often flower more profusely as they are making a last ditch attempt to produce seed before they die.

Soil tests

Carry out a soil test to check if you have acid soil (suitable for lime-hating or ericaceous plants) or alkaline soil (containing high levels of lime, calcium). Determine the pH (phosphorus hydrogen) level by using a simple soil test kit available from your garden retailer. The lower the level of pH, the more acid the soil.

Testing

When testing, carefully read the instructions in the soil test kit. These additional rules may help you get an accurate result:

1. Choose the areas of the garden specifically to be tested in turn.

2. Take the sample at 2 metre (2 yard) intervals across the area to be tested.

3. Remove a sample from 15cm (6in) deep using a trowel. Never handle the soil with bare hands.

4. Bring all the samples from a nominated area together in a clean dry container and mix well to provide an average sample.

5. Use distilled water, rainwater or boiled water to carry out the test.

6. Compare the test with the colour chart on the test pack and permanently record the results.

If the reading is alkaline then it is normally best to avoid lime-hating (ericaceous) plants. On very acid soils alkaline requiring plants can be grown by adding garden lime to lower the acidity. Raising acidity is much harder and often leads to failure.

Plants for different levels of pH

Plants normally fit into the following scale:

Acid lime-hating plants - pH4 to pH6 (acid-loving, lime-hating ericaceous plants)

Neutral, neither acid or alkaline - pH6 to pH6.5 (semi acid-loving plants)

Alkaline - pH6.5 to pH8 (lime-loving plants)

Whereas lime-hating plants will only grow on acid soil, lime-loving plants will grow well on any soil type.

Lime hating plants

Trees
Acer rubrum (Red Maple) Stuartia Acer-Snake Bark varieties*
Styrax (Japanese Snowbell)

Shrubs
Azaleas
Calluna (Summer flowering Heather)
Camelia*
Erica (Summer flowering Heather including tree Heathers)
Gaultheria (Box Berry)
Hamamelis (Witch Hazel)*
Kalmia (Calico Bush)*
Pieris (Lily of the Valley shrub)
Rhododendrons
Skimmia*
Vaccinium (Blueberry)

	Camelia
	Azalea
	Rhododendron

Alpines
Gentiana (Gentian - some varieties)
Lithodorna

*These plants will tolerate up to neutral level of pH.

Feeding

Applying a general fertilizer to the soil in mid Spring will help growth and build up root clumps, which in turn will produce more leaves and improve flower performance. If signs of yellowing (chlorosis) are identified, a trace-element fertilizer such as Miracid will relieve the situation.

Watering

Lime-hating plants have fibrous root balls so it is important that this is kept moist by regular watering. Mulching with lime-free compost each Spring will help conserve valuable moisture.