Friday, October 14, 2011

Acid-loving Plants

There is a group of plants called the acid-lovers. The most beautiful of these are the azaleas, rhododendrons and camellias. These plants like soil that is acidic and do not like any kind of lime or alkaline soil.

Acid-loving plants do not tolerate clay soils as they easily become waterlogged. The result is leaf scorch, indicated by brown patches on the leaves and a wilted appearance.

Rhododendron ‘Pink pearl’ will grow both in full sun and in dappled shade. When planting out you do not need to tease the roots, which should be tight and compact. Ensure that the top of the root ball is just below the soil surface. These plants do not require a lot of fertiliser and excess can retard growth, so don’t put fertilisers into the planting hole.

How do you keep the soil acidic? Mulch around the plant with compost, old cow manure and blood and bone. You can also use half-decayed leaves or pine needles because they are highly acidic. Always keep the mulch free from the stem or it will go mouldy.

These plants are poor at obtaining iron and alkaline soil can induce iron deficiency which can be identified by a yellowing of the leaves. The reason why these plants love acid soils is because they can obtain more iron under these conditions. Iron can be supplemented in the form of cheated iron, bought as a yellow powder. Place a large spoonful into a watering can and water over the leaves and into the soil. This type of iron can bypass the alkalinity and be absorbed readily by the plant, however it is only a temporary solution and long-term remediation of the soil may be necessary.

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