Loose Garden Surfaces

This is an excerpt from the Book called “Paths & Paving . Continue reading to learn more about Loose Garden Surfaces, thanks to the author.

Loose Surfaces 

Loose materials, whether gravel, stone or bark chippings, are inexpensive, simple to lay, and the ideal choice for areas that incorporate curves-loose materials fill even the most awkward niches without complex cutting.  Aesthetically, they create an intermediate texture between hard paving and the softer lines of planting, and they provide an ecologically sound and labor-saving alternative to lawns, needing no feeding, watering, or mowing. 

A Simple Graveled Area 

If properly laid, gravel is a most versatile and practical medium.  It makes a natural link between areas, plants can be planted through it for dramatic or subtle effect, and it permits self-seeders to spread at the edges in pleasing drifts.  But for ease of maintenance, comfortable walking, and free passage of wheelbarrows, it is most important to lay gravel on a firm, level, and well-compacted subbase that is cleared of fertile topsoil and free of weeds. 

Choosing Gravel 

  • Gravels are available in different grades and finishes, obtained as rough chips from parent rock or as dredged, water-worn pebbles.  Choose a grade to suit your purpose.  Grades less than ¼in/6mm create fine texture but are readily carried into the house on the soles of shoes; any much larger than ½in/12mm are uncomfortable to walk on.   
  • Buying gravels from a local source can save expense in transportation and may simplify obtaining a color range that blends with the materials used in the house and other garden buildings.
Choosing Gravel
Choosing Gravel

You Need: 

Materials  

  • Equal parts small-grade decorative gravel and large-grade compactible gravel 
  • Bricks and mortar or boards and sakes to make holding edge 

Tools 

  • Spade 
  • Rake 
  • Wheelbarrow 
  • Power compactor or heavy roller 

Preparing The Base 

  1. Having chosen your site, clear the ground weeds (it is especially important to eradicate perennial weeds such as bindweed) and remove a 4in/ 10cm layer of soil from the area.  Edge the area with bricks in mortar or treated lumber to keep gravel off the lawn.  Alternatively, you can let it merge into a flower bed.
  2. To prepare the base for graveling, rake the soil level, then fill the excavated area with compactible gravel, or road stone, almost back up to original ground level.  Rake the surface completely flat.
  3. Using a power compactor (which can be rented) or heavy garden roller, compress the base to remove air pockets and thereby provide a stable base.  The base needs to be compressed to at least 3/4in/2cm below original ground level.
  4. Once you have achieved a firm, compacted base, add the decorative gravel, starting at one side and spreading it as you go.
  5. Using a rake, work over the area to create an even surface.  The finished level should be just below the edging so that gravel cannot stray onto the lawn.  You may then decide to introduce some plants into the area, perhaps to soften edges near beds and borders or for architectural effect.

Planting In Gravel 

  1. Scrape the surface gravel to the one side and dig a hole, slightly larger than the plant’s rootball, through the gravel base and into the soil below.
  2. Fill the hole with compost.  Gently tease out the plant’s roots, then plant so that it is almost level with the surrounding gravel.
  3. Place some of the removed soil around the rootball and firm in.  Replace gravel around the stem and under leaves, then water in.

Using Geotextiles  

The use of geotextiles, or landscape fabrics, makes laying gravel and other loose surface materials such as bark simple.  Geotextiles, made from heat-bonded polypropylene, form a permeable barrier between soil and surface material, helping to suppress weeds yet allowing air and water to pass through.  The soil stays healthy and maintenance is kept low.  The lightest weights are ideal in gardens and, if properly laid, should last a lifetime. 

Laying And Planting Through Geotextile 

  1. Remove a layer of soil 1½in/4-5cm deep, level the area, and lay the geotextile over the surface.  Secure the edges with small wire hoops to keep them flat.  If gravel butts up to a lawn, install edging boards to keep it in place.
  2. To plant through the geotextile, make a crosswise slit big enough to hold the rootball.  Dig a planting hole and spread out plant roots.  Backfill, firm in, and water. Fold back the geotextile around the stem.
  3. Add the gravel (or bark).  Start at one side and spread it as you go, taking care not to damage plants.  A 3/4in/2cm layer gives sufficient coverage for most purposes.  Finish by leveling with the back of rake.
A Simple Graveled Area
A Simple Graveled Area
Planting In Gravel
Planting In Gravel

How Geotextile Works 

A geotextile fabric greatly extends the life of a gravel, bark, or other loose surface, since it prevents chips from eventually becoming incorporated into the soil or subbase.  It makes a light-excluding layer that helps prevent the germination of weed seeds.  Because it is permeable to water and air, it does not deprive the soil and plant roots beneath of vital oxygen and moisture as black plastic does; neither does it allow the accumulation of surface water.  Applications of fertilizer will be washed down to plant roots.  Geotextile also offers the additional benefit of keeping plant roots cool in summer and reducing the depth of freezing in winter. 

Plants For Gravel 

Gravel drains freely and reflects light and heat, so choose plants that thrive in these conditions.  Drought-tolerant plants, such as silver-leaved plants from the Mediterranean, are ideal. 

Rapid drainage also makes gravel an ideal home for robust alpines.  Like plants that prefer dry conditions, these may succumb to winter moisture.  Gravel is a perfect foil for architectural plants. 

Choice Plants 

Plants with silvery leaves, such as this group of Verbascum, thrive in gravel; their foliage, especially if felted or hairy, is seen at its best-unsullied by soil and rain splash.  The outlines of spiky architectural plants, such as those of many grasses and Phormium, stand out beautifully.  Self-seeding plants such as fennel (Foeniculum) lend informality; be ruthless about pulling out unwanted seedlings, or cut off heads before seeds can disperse. 

Good Choices For Gravel 

For Informal Plantings 

Anthemis tinctoria 

Centranthus ruber (valerian) 

Dictamnus albus 

Dryas octopetala, D. drummondii 

Foeniculum vulgare ‘Purpureum’ (bronze-leaved fennel) 

Hyssopus officinalis(hyssop) 

Lavandula (lavender), many 

Lychnis coronaria 

Origanum laevigatum 

O.vulgarae 

salvia officinalis (sage) 

For Architectural Impact 

Acanthus spinosus 

Agapanthus, many 

Allium, many 

Cynara cardunculus (cardoon) 

Eremurus robustus 

Eryngium, many 

Euphorbia, many 

Onopordum acanthium 

Phormium, many 

Verbascum bombyciferum, 

V. ‘Cotswold Queen’, V.olympicum

Yucca flaccida, Y. gloriosa