Top dressings:
hiding bare soil and enhancing the look of your plant displays

Why use top dressings? In the bad old days, top dressings weren’t needed. That is because interior landscapers thought it would be a good idea to stuff ugly containers with so many plants that the soil could not be seen. Luckily, those days are gone and we now tend to make use of single characterful specimens in good quality containers. Often, the plants have trunks and the soil surface is left exposed.

Why bare soil is unacceptable

Firstly, and most importantly, it is ugly. Unless the soil surface is constantly refreshed and tidied, it soon looks tired. If the plants are top watered, you end up with damp and dry patches and hollows where a torrent of water hit the surface.

Secondly, it accumulates rubbish. Dead leaves and office litter often find their ways onto the soil surface, which is difficult to keep tidy.

Thirdly, the soil surface is where fungus gnats (sciarid flies) breed. If you can stop them getting there, then you will not have a problem with them.

Types of top dressing

There are dozens of different materials that are used to cover the surface of the soil in a container. The most common are bark, gravel, cobblestones and Spanish moss. These four materials probably make up over 75% of the top dressings used worldwide. More recently, however, a wide range of new products have become available. These include:

• Recycled glass chippings

• Crushed sea shells (sometimes dyed)

• 'Coffee beans' - spray painted gravel in many colours

• Marble chippings

• Slate chippings

• Mock bark, made from recycled car tyres, often in different colours

• Chipped quartz and other semi-precious minerals
  

Factors that affect your choice of top dressing

The most important factor to affect your choice of top dressing is how it looks with the plant AND the container. Sometimes, a contrast between a dark container and a pale dressing looks really good. However, the dressing should never overwhelm the plant, especially if it doesn’t have a defined trunk.

Modern containers look best with a contemporary dressing. Polished or brushed metal, especially silver, looks very good with glass or marble chippings. Older, more traditional containers benefit from the use of older, more traditional dressings, e.g. bark or moss. One other very important factor to consider is how the plant display is watered.

Top dressings to avoid

We do not recommend the use of heavy cobbles, as these compact the soil and will shorten the life of the plants. If you have staged plants, heavy cobbles may destabilise the display and the plant may lean to one side. These should also be avoided in public places such as shopping centres where unruly children may throw them around and cause damage.