Acid Loving Plants

Ericaceous plants are a group of plants that prefer to grow in acidic (lime free) soils. They include Heathers, Pieris, Rhododendron and Azalea, Camellia and Pernettya. Although the word ericaceous is used for acid loving plants the correct term is calcifuges.

If your soil is only slightly acidic then it is possible to grow a wide range of plants, apart from those requiring very alkeline conditions. The pH (level of acidity or alkalinity) can be easily measured using a home soil testing kit; if your soil is above pH 6.5 then it is unsuitable for acid loving plants. If your soil is on the alkaline side it is still possible to grow acid loving plants using raised beds filled with special ericaceous compost or growing the plants in containers. It is advantageous to top dress annually with more ericaceous compost and re-test the pH of your soil.

Lowering the acidity of a lime rich soil is difficult but chemicals such as chelated iron can be added to plants showing signs of chlorosis.

Azaleas & Rhododendrons
Rhododendrons are a group of evergreen shrubs that grow from 1ft (30cms) to 20ft (6m), they flower in spring and come in a range of colours. Azaleas can be evergreen or deciduous, the evergreen ones are normally low and spreading, they usually flower prolifically in May. The deciduous ones are taller and can grow to 6ft (180cms) or more. Deciduous azaleas normally have good autumn colours.

Heathers (Calluna and Erica)
It is possible to have flowers all year round with heathers, most prefer moisture retentive soil in an open sunny position. Erica carnea and its cultivars will tolerate some lime in the soil. Heathers are best planted in groups and should be given a light trim after flowering.

Camellias
Evergreen shrubs that grow to 6-8ft (180-240cms) with flowers in early spring. Cold winds and frost can damage buds so a sheltered site is required, it is best to avoid north or east facing aspects.

Pernettya
Evergreen shrub growing to approximately 3ft (90cms) tall. White flowers in spring are followed by round berries of various colours. They require moisture retentive soils in sun or light shade. Both male and female plants are required to produce berries.

Pieris
Another evergreen shrub that can eventually grow to 10ft (3m) tall. They have narrow leaves and white, pink or purple bell shaped flowers but they are usually grown for their bright new foliage in spring, varying from green to crimson and bronze. They prefer semi-shady sites and are ideally suited for pots and containers. There are many cultivars with varying leaf and flower colour. 'Forest Flame' (pictured) has young leaves that start bright red and slowly turn through pink, cream and finally green.

Kalmia (Beauty Bush)
Evergreen that flowers in early summer with pink, white, purple or red flowers. They grow to around 2ft (60cms). All are poisonous to livestock.

Other plants that prefer a neutral to slightly acidic soils include Acer, Magnolia, Hamamelis, Skimmia and Mahonia.