Right Plant, Right Place. Part One, Soil

Plants are more at risk from poor planting than from pests & diseases. So following the mantra of right plant, right place is key to successful growing…

Hedge Planting at Hedge Xpress

Photinia Red Robin 70-90cm

£17.95 exc. VAT

Right Plant, Right Place

Most of the plants in our gardens have come from elsewhere, whether that is another country, another continent or simply another part of this country. Their point of origin is where they have evolved, adapting through millennia to specific soils and climates. That is part of their DNA and even if we create hybrids and cultivars that introduce genetic attributes more in keeping with their proposed new home, a shade-loving plant will always be that. Besides, you don’t have to travel thousands of miles to encounter differing conditions – hop over the fence and you may well find that the fundamental characteristics of your neighbour’s garden are completely different to yours.

To ensure the rules of right plant, right place are followed, six criteria need to be met. In no particular order (one of these criterion is no more important than another), these are:

  1. Soil Type
  2. Soil pH
  3. Sun or Shade
  4. Wet or Dry
  5. Frost and Wind Resistance
  6. Coastal Locations

We’ll cover all six in this and the following two posts…

  1. Soil Type

While experts can sub-divide soils into a myriad of types, the gardener only needs to recognise four – and they are highly distinctive: sand, chalk, loam and clay. The key factor with soil, though, is that the addition of grit and organic matter can transform more extreme soils so that they will accommodate just about any hedging plant you choose.

The following hedging plants are happy in both clay and chalk:

For clay soils:

  • Hornbeam

For chalk soils:

  • Perovskia Blue Spire AGM
  1. Soil pH

Acid, neutral or alkaline? This guide from the RHS explains:

pH 3.0 – 5.0: Very acid soil

  • Most plant nutrients, particularly calcium, potassium, magnesium and copper, become more soluble under very acid conditions and are easily washed away
  • Most phosphates are locked up and unavailable to plants below pH 5.1, although some acid tolerant plants can utilise aluminium phosphate
  • Acid sandy soils are often deficient in trace elements
  • Bacteria cannot rot organic matter below pH 4.7 resulting in fewer nutrients being available to plants

Action: Add lime to raise the pH to above 5.0. The addition of lime can help break up acid clay soils

pH 5.1 – 6.0: Acid soil

Ideal for ericaceous (lime-hating) plants such as rhododendrons, camellias and heathers

Action: Add lime if other plants are grown

pH 6.1 – 7.0: Moderately acid soil

  • A pH 6.5 is the best general purpose pH for gardens, allowing a wide range of plants to grow, except lime-hating plants
  • The availability of major nutrients is at its highest and bacterial and earthworm activity is optimum at this pH

Action: It is not usually necessary to add anything to improve soil pH at this level

pH 7.1 – 8.0: Alkaline soil

  • Phosphorus availability decreases
  • Iron and manganese become less available leading to lime-induced chlorosis
  • But an advantage of this pH level is that clubroot disease of cabbage family crops (brassicas) is reduced

Action: Sulphur, iron sulphate and other acidifying agents can sometimes be added to reduce pH. Clay soils often require very large amounts of acidifying material and soils with free chalk or lime are not usually treatable

Hedging plants aren’t generally fussy and will thrive in a pH of 5.5 – 8.5 and often in lower or higher pHs. It is worth noting that Cherry Laurel doesn’t like a low pH.