Plants on Acid. The 'high' that's entirely legal

Plants on Acid. The 'high' that's entirely legal

Garden plants on acid, and it's all legal!

Some plants just love to take a trip on acid. And this is not something that attracts disapproval. In fact there are whole families of plants that are on a permanent ‘high’, because that is exactly where they originate from. Rhododendrons, for example, like to live on steep slopes that lead down into valleys in the Himalayas and south eastern Tibet. Himalayas, rhododendrons, acid, soil, ericaceous, plants The Himalayas are home to plants such as Rhododendrons! Hydrangeas are native to southern and eastern Asia from Japan to China and they also grow well on the slopes of the Himalayas and Indonesia. Hydrangea, acid, soil, plants, ericaceous There are many types of Hydrangea and their parents originated from Tibet, China and Asia! Acers hail from Japan; North and South Korea and south east Russia. Acer, acid, soil, ericaceous, plants, trees Japanese Acers are acid lovers. Camellias originate from China and Japan. These are all plants that like mountains, slopes and free-draining areas where there is plenty of mulch. The thing they don’t like is lime. And they are not too keen on wall-to-wall sunshine either.   Camellia, acid, soil, evergreen, plant, shrub, tree Camellias are acid lovers. Their evergreen, waxy leaves are beautiful all year round Let’s look at what we mean by ‘acid’. It’s a soil thing. The lower the pH value of the soil, the higher the acid content. Acid soil has a pH of no more than 5.5 for most of the year. Neutral pH is around 7 and a neutral range of soil would be between 6.5 – 7.5. Extremely acidic soils are 4.5 or below, and few plants could live in conditions that have a lower pH than this.   ph SCALE, soil, acid, alkaline The pH Scale: the lower the number, the higher the acid content of soil What does all this mean to the gardener? It’s always wise to check your plants’ preferences before planting. PH is a measure of the hydrogen-ion concentration and plants find it difficult to access certain nutrients if the soil pH is outside their acceptable range. Acid soils are associated with certain toxicities such as aluminium and deficiencies including the chemical element, molybdenum. Hydrangeas are one of the few plants that accumulate aluminium. It congregates within the hydrangea flower and it is this that gives the blooms their blue colouration. Hydrangea macrophylla Teller blue lace cap Hydrangea macrophylla 'Teller Blue' is a lace cap variety   Blueberries have a specific liking for acid soil, as do azaleas; heathers; magnolia; hostas and rowan trees (Sorbus). There are many plants that are tolerant of acid, including mahonias; asters; crab-apple and many ornamental grasses. Hosta Christmas Tree, plant, garden, acid, soil Hosta 'Christmas Tree' is tolerant of many different types of soil, including acid.   How does the gardener manage plants that are addicted to acid? These lime-hating plants will show signs of leaf-yellowing (chlorosis) if they are trying to cope with too much lime. You can add sulphur to the soil in order to make it slightly more acid. Soil organisms convert this into sulphuric acid. It does, however, take quite a few weeks or even months, to take effect. Other options include adding aluminium sulphate, which is the hydrangea ‘blueing agent’. The effects happen quickly but it can eventually interfere with phosphorus levels in the soil. It can also cause a build-up of aluminium in the soil. Ferrous sulphate can also be used in a similar way.   Chlorosis, camellia, leaf, yellow, acid, alkaline, soil Camellia leaf showing chlorosis, turning yellow. Testing the pH of soil is simple. There are many inexpensive kits available from garden centres and retail outlets and it’s quick and easy to do. It involves taking a sample of soil; mixing it with rain water and doing a dip-stick test.  Bear in mind, however, that the soil readings can vary from place to place in the garden because of the underlying rock and the effects of mulching.   PH test, soil, acid, alkaline pH testing kit: they are simple to use.  

Ericaceous (lime-hating) plants

Acid lovers generally have a shallow root system and they therefore don’t like to dry out. They prefer a slightly shady site and need to be able to access the iron and other soil nutrients that are ‘locked up’ in soil that has a higher pH value. Got alkaline soil? Grow ericaceous plants in containers, then you will be able to grow almost anything you want! Good feeding is important for containerised plants and you can use either slow-release pellets or regular applications of liquid feed.  Don’t allow your pots to dry out!   Acer in pot, soil, plant, acid, alkaline You can grow acid-loving plants in pots so you have complete control over the soil. Why do we love ericaceous plants such as camellias, rhododendrons and azaleas? Part of the appeal lies in the fact that the blooms are so ‘blousy’ and extravagant! And because of the fact that the spring flowers are uplifting at a time when most of us feel deprived of flower power! A grove of azaleas and rhododendrons in full flower is an awe-inspiring sight and a visit to somewhere such as Wakehurst Place in West Sussex will reveal the true splendour of these ericaceous plants. Advertised as ‘Kew in the country’, Wakehurst Place Garden belongs to the National Trust and is managed by the Royal Botanic Gardens. The gardens near the house are designed to an Arts and Crafts style and the woodland garden is a ‘picturesque’ or ‘gardenesque’ style. Brush up on your garden history before you visit and enjoy planning ahead as we approach the shortest day or the year! Find out more about Wakehurst Place here: www.kew.org. Buy your camellias here: www.perfectplants.co.uk It’s a GREAT time for planting.