Spring colour in the garden is often supplied by ericaceous plants such as Rhododendrons, Magnolias, Camellias, Azaleas, Pieris and even Japanese Maples (Acers) amongst others. These plants all have something else in common other than their flowering times, they are all acid-loving plants. Ericaceous plants are plants that don’t like growing in soils that contain lime. They are also known as acid lovers or lime haters. This means they won’t grow well in soils that have a high pH – such soils are referred to as alkaline.
If you try to grow ericaceous plants in alkaline or limey soils, they produce yellow leaves. This is a condition known as lime-induced chlorosis, where they don’t grow or flower well and usually, finally die. The main reason for this is that they need plenty of iron and other soil nutrients that become insoluble or ‘locked up’ in the soil at high pH, so the plants can’t absorb them.
Most ericaceous plants will grow in large pots filled with ericaceous (lime-free) compost. Growing ericaceous plants in containers also allows you to grow them in the right place in the garden. Most ericaceous plants prefer a position in light shade or out of direct sunlight, especially early morning sunlight, which can cause the flower buds and flowers to turn brown and drop off. You can test the pH of your soil using a soil testing kit (on a scale of 1 to 14, acid is between 1 and 7). If it’s slightly acidic, you can grow a huge range of plants. Another way to tell the pH of your soil is if you have mop-headed Hydrangeas growing in your garden. These plants typically display pink flowers in alkaline soils and blue flowers in acid soils.
Ericaceous plants will really do much better if fed with a specific ericaceous plant food. These contain all the specific nutrients needed for great green leaves and masses of fabulous flowers. This can either be a granular feed or a liquid feed, whichever you prefer. Continuous/slow release feeds are perfect for those who lack time to feed regularly as they feed for up to six months from one application. Liquid feeds are more suited to those who love the routine of regular feeding. Because Azaleas, Rhododendrons and Camellias set their flower buds from June to August, it is essential to keep them well fed during this period, as well as feeding in spring.
As most ericaceous plants, especially Rhododendrons, Azaleas and Camellias are shallow rooted, they are prone to drying out during prolonged dry periods. So it is very important to keep the soil or compost moist.
Magnolias can be evergreen or deciduous, but the deciduous varieties (lose their leaves in winter) are far more common in the UK. The reason is that they produce flowers when they have few leaves and this allows the beauty of the flowers to be seen much more clearly. They are one of the oldest plant groups still in existence today and date back at least 20 million years. They prefer full sun throughout the year but will also grow well in light shade. Some varieties are well suited to growing in containers, different varieties range from a height of 8ft and spread of 8ft up to 63ft height and spread, so choose your variety carefully, according to the space you have. Most varieties flower from late March to late May.
Rhododendrons originate mainly from the Himalayas where about 600 different species can be found. From these humble beginnings, plant breeders have developed more and more exotic hybrids over the past 100 years. With flowers in colours of red through pink, orange and yellow to white, and with blue and purple to add, they are a show that must not be missed. Rhododendrons grow best in dappled shade in sheltered conditions. Compact hybrids are ideal for containers on shaded patios, remember to water well as they are thirsty plants.
Nothing is more beautiful than an Azalea shrub in spring bloom. These easy- care shrubs come in so many colours it’s hard to find one that doesn’t suit your needs. Azaleas can be grown in nearly any garden, instantly adding interest and colour to drab areas. Growing and caring for these shrubs is easy. Azaleas make exceptional candidates for containers, but don’t forget to use ericaceous compost.
Pieris are a lovely, easy to grow showy spring shrub. Popular varieties such as ‘Mountain Fire’ and ‘Forest Flame’ have new growth which colours bright red in the spring, fading to pink and finally green with many long cream/white flowers in the spring. The shape and mass of white flowers gives Pieris its common name ‘Lily of the Valley’ bush. Its evergreen foliage gives cover all year round before giving great spring colour in March followed by flowers in April/May.
Camellias are one of the most popular winter-spring flowering shrubs, providing a vivid splash of colourful blooms above evergreen, glossy foliage when little else is in bloom. Although widely available, their size, habit and rate of growth varies immensely so be sure to get advice from your local garden centre to make sure you choose the variety to suit you. Although they need acid soil, they are easy to grow in containers of ericaceous potting compost. As well as a range of pink, red, white and cream blooms, Camellia flowers vary in size and shape too. They range from single, semi-double through to formal-double so pick the ones that appeal to you most.