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.
The Himalayas are home to plants such as Rhododendrons!
are native to southern and eastern Asia from Japan to China and they also grow well on the slopes of the Himalayas and Indonesia.
There are many types of Hydrangea and their parents originated from Tibet, China and Asia!
hail from Japan; North and South Korea and south east Russia.
Japanese Acers are acid lovers.
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 dont like is lime. And they are not too keen on wall-to-wall sunshine either.
Camellias are acid lovers. Their evergreen, waxy leaves are beautiful all year round
Lets look at what we mean by acid. Its 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.
The pH Scale: the lower the number, the higher the acid content of soil
What does all this mean to the gardener? Its 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' is a lace cap variety
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' 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.
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 its 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 testing kit: they are simple to use.
Ericaceous (lime-hating) plants
Acid lovers generally have a shallow root system and they therefore dont 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. Dont allow your pots to dry out!
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
Its a GREAT time for planting.