Gardens are a jigsaw puzzle: thriving, complex mini-climates, comprising many different elements. All these factors influence what you can successfully grow, so you need to get to know and understand them.

Direction

The direction your garden faces determines how much light it gets. Sun-drenched, south-facing gardens support totally different plants from those that face north. Pinpoint your garden’s direction with a compass. If it is small, note the orientation of boundary walls and fences, as it is along these that you will grow most of your plants.

East-facing walls get only strong morning sun. Plants grown here will also face bitter winds and extremes of temperature. West-facing walls get most of their sun in the afternoon and evening. “West is best,” so save this spot for your favourite plants that are a little on the tender side.

South-facing walls get very hot (the sun beats down on them most of the day) so use drought-tolerant plants such as rosemary and thyme here. North-facing walls only get an hour or so of sun each day, so are perfect for ferns, hostas and other shade-lovers.

Location, location, location

A big problem in city gardens is air pollution. Plants get knocked out by fumes and airborne particles and struggle to breathe. See what’s grown in local parks, on roundabouts and verges: these are the real toughies you should plant.

In cities — even those in the north — you will probably be able to grow some tender plants outside all year round because houses and office blocks act as giant storage radiators, soaking up the sun’s energy and releasing it at night when it’s cooler. Buildings also buffer the wind.

Coastal gardens have to cope with salty air, which burns delicate leaves. Where buildings offer no protection, choose salt-tolerant plants such as junipers, hydrangeas and honeysuckle.

Overexposed

Consider wind exposure. Seaside gardens and their urban equivalents, balconies and roof terraces, do suffer; without protection, delicate plants will be reduced to ribbons. Forget dainty Japanese maples and choose tough ornamental grasses, choice evergreens and carpeting shrubs.

Watch out, too, for frost pockets in larger gardens. These are often found in hollows or at the bottom of a slope. Frost is heavier than air, so it seeps down to the lowest point. Fortunately, these pockets are easy to spot. Look for areas where the soil is still rock- hard long after the rest of the garden has thawed. Choice exotics here are obviously out.

Shade and shadow

Mature trees can cause problems because they shade out the sun and suck up water and nutrients, leaving little for other plants. Tough nuts such as lily-of-the-valley, bleeding heart and dead nettles are the solution here. These need no cosseting and quickly colonise dry, shady spots beneath trees.

Plants at the base of tall walls suffer from similar ills: the wall casts a “rain shadow” over adjacent flowerbeds, preventing water from getting to the roots. The problem gets worse if the wall is hot, sunny and faces south. Where possible, plant out a foot or so from the wall, so the roots catch some rain, and mulch the surface of the soil with a thick layer of composted bark to help stop evaporation.

The good earth

Soil is the lifeblood of any garden. Clay soils are a doddle to spot: simply think of pottery classes. Wet clay soil is sticky, holds its shape easily and smears in your palm. When dry, large cracks will appear and it is hard to dig. For clay soils that get waterlogged in winter, choose moisture-lovers and bog plants, such as ornamental rhubarb, ferns and bergamot.

Sandy soils feel gritty and won’t roll into a ball. They don’t get waterlogged, but nutrients wash away easily and the soil will dry out fast, especially in a hot, south-facing spot. Californian plants, such as ceanothus, and Mediterranean herbs, such as rosemary and oregano, just love it.

Luckily, most soils are a mixture of sand, silt, clay and humus (composted plant remains). Whatever soil you have and however bad it is, adding compost can dramatically improve it. Spread a 3in layer over the surface and fork it in thoroughly.

Chemistry lesson

Soil is either acid or alkaline. Buy a pH test kit at your local garden centre and play scientist for an hour or so to find out what you’ve got. If the reading is below seven it is acid; if it’s above seven it’s alkaline with a high lime content; pH7 is neutral.

Chalky soil is very alkaline, and only plants such as buddleia, old-fashioned pinks and clematis will flourish. Don’t plant acid-loving witch hazel or camellias here — these are lime-haters that will yellow and die.

Don’t try to change the pH of your soil; work with what you have. If you are determined to grow acid-loving rhododendrons but your soil looks like the white cliffs of Dover, there’s an easy solution. Grow them in pots filled with ericaceous (lime-free) compost.

Explore Property

• Buying & Selling

• New Homes

• Overseas

• Interiors

• Investment

• Gardens

• Cool In Your Code

• Specials

Times recommends

• Analysis: frustration for everyone - except investors
• Spanish property: why it's crunch time on the Costa del Sol
• Buy-to-let: professional investors cash in on the credit crunch