City of Toronto: Toronto Water - Water efficiency - Building your water-efficient garden

This section provides advice to help you design, plant and grow your very own water-efficient garden.

Planning your garden
Planting your garden
Alternatives to traditional gardens

Planning your garden

Space

If you already have an open space of soil for your garden, you can skip to the next section.

If you are going to be replacing your lawn with a natural garden — congratulations! Not only will you be creating a trendy and stylish landscape while saving water, you'll also be saving yourself time in the summer months — time you don't have to spend watering, mowing, fertilizing and weeding your lawn.

There are generally three ways to convert a portion of your property from lawn to garden. Choose the method that best suits your abilities, time and pocketbook.

Completely removing the sod

This is the most physically challenging way to convert lawns into natural gardens.

Cut and remove sod with proper garden tools (straight edged spade or rented sod cutter) from the area which you want to place the garden.

Because remaining grass roots can re grow, consider adding a light layer of newspaper over the exposed soil. This will prevent the grass root from re-establishing.

Spread 10 — 15 cm (4 — 6 inches) of organic compost over the area.

Build a garden bed on top of existing lawn

This is an easy method, but only if the height of the desired area can be raised by a minimum of 15 cm (6 inches). To make room for larger vegetation like trees and shrubs, it may still be necessary to remove the sod and dig the hole deep enough so the top of the root ball is only slightly above the new grade.

Mow the lawn of the area very short.

Spread five to six layers of newspaper over the area.

Add a minimum of 15 cm (6 inches) of good compost.

Solarization

This process takes the longest, but done properly, provides the best results. Using the sun's rays, you can kill the existing grass, its roots any weeds and their seeds through the heat and 'solarization' from the sun.

Mow the area as short as possible.

Cover the area completely with a thick black plastic. Weigh down the plastic to avoid sun or air getting in at the sides.

Leave this for 6 — 8 weeks in advance of planting. Times will vary according to the weather. Hot sunny weather will take much less time than cold, wet weather.

After a few weeks, check to see that all grass is dead and at least partially decomposed.

Once the grass has been killed off completely, you can add 10 — 15 cm (4 — 6 inches) of compost on top.

Site Conditions

Before you start any project, you will need to determine the existing site conditions to make sure you create the right layout and choose the most appropriate selection of plants. For example, if you are planting in an area with a steep slope, water drainage may be affected and maintenance may be difficult.

Selecting the right plants for your garden is also about matching its needs to the sun and soil conditions of the location to be planted. The right plant in the right place will require less attention.

How much sun do you have?

Plants have adapted to a variety of conditions in nature, including the level of sunlight they require each day. Determining what plants to choose for your landscape is very dependant on the how much sun your landscape receives each day. These terms appear on plant tags at garden centres so it's helpful to know how they are defined.

Sun: At least 6 full hours of direct sunlight.

Partial Sun / Partial Shade: 3 — 6 hours of sun each day.

Full Shade: Less than 3 hours of direct sunlight each day.

Sun Exposure

Take note of how much sun your planned garden will receive throughout the day. Remember to look for existing vegetation and other surrounding features (like decks, patio sets, etc) that may cast shadows and change the amount of sun your garden is exposed to throughout the day.

Also, be aware of the seasonal changes of sun exposure. As deciduous trees get their full summer canopy, a sunny spot in the spring may turn into an area of full shade in the summer.

Soil

Soil provides support, nutrients and water to the plant. In general, most plants grow by absorbing nutrients and water from the soil. Their ability to do this depends on the nature of the soil. Depending on where you live, soil contains some combination of sand, silt, clay and organic matter.

Most soils will require some addition of nutrients to allow for ideal growing conditions. Adding organic material to your soil will increase its ability to hold more moisture, for longer, while feeding your plants with all the nutrients they need. Good soil is the key to all great gardens!

Soil nutrients

Sometimes, the nutrients that plants need occur naturally in the soil. Other times, they must be added. The mineral nutrients, which come from the soil, are dissolved in water and absorbed through a plant's roots. There is not always enough of these nutrients in the soil for a plant to grow as well as we would like.

The mineral nutrients can be divided into two groups: macro-nutrients and micro-nutrients.

Macro-nutrients

Macro-nutrients can be broken into two more groups: primary and secondary nutrients. The primary nutrients are nitrogen (N), phosphorus (P) and potassium (K). These major nutrients are used in large amounts by plants for their growth and survival, so they are usually depleted faster from the soil.

The secondary nutrients are calcium (Ca), magnesium (Mg) and sulfur (S). There is usually enough of these nutrients in the soil so fertilization is not always needed. However, deficiencies in any of these nutrients can impact a plant's success.

Micro-nutrients

Micro-nutrients are those elements essential for plant growth which are needed in only very small (micro) quantities. These elements are sometimes called minor elements or trace elements. The micro-nutrients are boron (B), copper (Cu), iron (Fe), chloride (Cl), manganese (Mn), molybdenum (Mo) and zinc (Zn). Recycling organic matter such as grass clippings and tree leaves is an excellent way of providing micro-nutrients (as well as macro-nutrients) to growing plants. Adding compost to lawns and gardens is another great source for both macro and micro-nutrients.

Tip

Homemade composting is a natural and inexpensive choice to add nutrients to your soil.

Other alternatives to add nutrients to your lawn include:

Composted manure — an odourless organic farm by-product used as a plant food to enrich potting mix and seed beds. Dehydrated manure is basically the same, but with less moisture.
Humus/Compost — consists of decayed organic matter used to add fertility, hold moisture and provide aeration.
Mushroom compost — a mixture of straw, peat moss and other organic components, its primary purpose is for use in commercial mushroom production. The mixture is only used once for mushrooms, then sold to consumers and is a great by-product for use in the garden.

Do-it-yourself project:
Find your soil's composition and improve it!

Fill a large jar 1/2 full of water and add a cupful of soil.
Place the lid on the jar and shake and/or the swirl the contents well to assure proper mixture.
Place jar in an undisturbed area for 24 hours and analyze the results as detailed in the diagram below.

Layer 1 (top of jar)
Organics suspension at top of jar

Layer 2
Water (no soils)

Layer 3
Silt - dusty layer at top soil content

Layer 4
Clay - reddish/brown

Layer 5
Sand - Light coloured

Tip

To enhance all soil types add organic content, preferably compost.

The distribution/amount of one soil type to another within the jar will provide you with a proper tool to characterize your soil type. Following completion of the test, you can use the following rules to characterize your soil type:

Sandy soil

Contents of jar will display a large distribution of sand particles (approx. 1/3 or greater). Sandy soils can dry out very quickly following periods of watering.

Clay soil

Contents of jar will display a larger distribution of clay (approx. 1/3 clay or greater). With the extreme hardness in dry times and compaction properties during wet periods, clay soils can create problems in trying to establish finicky plants within your landscape.

Loam soil

Contents of jar will display an equal balance of clay, sand and silt. Loam soil is an ideal soil type for all types of gardening.

Silt soil

Contents of jar will display a larger distribution of silt (approx. 1/3 silt or greater). Silt soils have the ability to retain more moisture than what is required by most plants.

Note: The two types of soil most commonly found in Toronto are clay and sand.

Your preferences

Plants come in all shapes, sizes and colours (see plant list in section 6.0), so your garden is not limited by the plants available, but what type of "look" you would like to achieve.

Some questions to ask yourself when designing your water-efficient garden:

Is an English cottage garden more your style, or do you like a formal, sculpted landscape?
Do you prefer flowering plants or non-flowering types?
Do you like a mix of colour in your garden or do you have favourite colours you would like repeated?
Is the tall, layered bed or border your preference, or would you rather have a rock garden or a scree bed?
Do you want your garden to have trees or shrubs in certain areas to block out neighbours, eyesores, or high sun/wind areas?
Do you want to plant trees to shade your house and help reduce heating/cooling bills?
Do you want to create a quiet and private place in your yard to "escape" from the busy city?

Knowing the answers to these questions before you visit the garden centre will ensure you pick the right plants to create the garden or landscape you desire.

Next section also contains some sample landscape plans to help you get started on your new garden.

Planting your garden

When you have designed your garden and chosen your plants, it is time to plant.

Timing

To ensure that your lawn and gardens become established and grow well, plant in the spring (May to June) or early fall (September to October). Each of the sample layouts and plants included in this manual may be planted in either spring or early fall.

Types of flowers

Perennials

Perennial plants will come back every year, usually blooming for several weeks and don't require much maintenance. Digging out and dividing (splitting the plant in half) in the fall every three years will keep your perennials looking full and healthy. Removing the dead leaves can be done after the winter as they act as their own mulch and winter protection.

Annuals

Annuals need to be planted every year, but can be sometimes self-seeding depending on the plant. Annuals are a popular choice as they bloom continuously throughout the summer. Plants that are annuals in our climatic zone may be perennials in warmer zones. Examples include Portulacas and Petunias.

Biennials

A biennial plant is a flowering plant that flowers in its second year and then dies. In the first year the plant grows leaves, stems and roots. The plant will survive over the winter and in the next spring or summer, the stem of the biennial plant will grow significantly. The plant then flowers producing fruit and/or seeds, before finally dying. Examples include Hollyhocks and Dianthus.

Self seeding

Self seeders are annuals that will drop their seeds which will grow into new plants. Although the annual parent plant cannot survive over the winter, their seeds can. Examples include Poppies and Cosmos.

Mulch, mulch, mulch

No matter what site conditions you are planning for, remember: mulch is a garden's best friend! That's because it controls weeds, keeps moisture in the soil and improves the health and appearance of your garden. To get the most out of mulch, place it on your soil and around your plants, vegetables, shrubs and trees.

How to apply mulch:

Apply mulch in the late spring before the hot weather arrives and when your perennials and annuals are becoming established but still small enough to work around.
Before you buy mulch ask for suggestions at your local garden centre although commonly available mulches work well in Toronto landscapes. However, your plants may benefit from a certain type.
Check the depth of existing mulch. Don't exceed the specified layer, as follows:

Place 2.5 — 5 cm (1 — 2 inches) layer if it's fine mulch (example, cocoa shells)
Place 5 — 10 cm (2 — 4 inches) layer if it's coarse mulch (example, bark chips)
Apply evenly. Level the mulch out with your hands or lightly rake.
Don't pack it down or compact the mulch.
Give the mulch a good soak. Use a watering can, hose or a soaker hose run underneath the mulch.
Pull the mulch away from plant stems and tree trunks. This allows good air flow to the base of the plant. For tree trunks, pull it back several inches creating a "donut" shape. Avoid piling mulch near trunk of tree; mulch "volcanoes" can cause additional problems including a dead tree. For new trees, mulch should be placed to the tree's drip line or beyond. (The drip line is the outer perimeter of the trees branches).
Check mulch thickness each year. Maintain the specified depth for the type of mulch you use.

Why your garden needs mulch

Mulch reduces water loss. Exposed soil loses water very rapidly to the air and mulch prevents moisture from evaporating, reducing the need for costly watering. It is estimated that mulch can reduce water evaporating from the soil by up to 70%. Mulch has several uses such as:

Insulates the soil. Applying mulch helps maintain an even soil temperature day and night, keeping soils cooler in the summer and warmer in the winter. When soil gets too hot in the sun, roots will stop functioning properly. Mulch prevents this from happening, protecting your plants.
Control weeds. Mulch can block out the sunlight that weed seeds need to grow. Keep in mind some mulches work better than others to suppress weed growth. For example, coarse mulch like bark, wood chips or shredded wood can block weed growth up to 90%. Another benefit — if a weed does grow it’s easy to pull out of the mulch.
Looks great. Mulch provides a neat, colourful, aromatic and attractive look to your landscaping.
Improves your soil. Organic mulches gradually break down in the soil returning valuable nutrients to your garden plants and trees. For example, mulch applied to sandy soil improves growing conditions and helps the soil retain water. For clay soil, using mulch loosens compacted soil and improves drainage.
Protect your plants. Adding mulch gives your plants another layer to grow in and prevents soil from becoming hard and dry. Soil covered with mulch protects plant roots, ensuring that plants won’t dry up.
Protect your trees. Place mulch around trees to reduce the likelihood of damage from yard trimmers and lawnmowers.

Mulch types

There are two types of mulch:

Organic:

Organic mulch is derived from plants. It's available at most garden centres, nurseries and home improvement retailers in the city of Toronto.

Pine needles

Chipped or shredded wood

Cocoa-bean hulls

Compost

Leaves

Straw

Organic mulch decomposes back into your soil at different rates, depending on what type you use. Remember to turn the mulch each spring to ensure circulation of air to the soil and to discourage pests.

Inorganic:

Inorganic mulch is a viable option to shade the soil and reduce moisture loss, but doesn't improve soil conditions or add nutrients to your garden. Inorganic materials are sold at most garden centres, nurseries and home improvement retailers in the city of Toronto.

Types of Inorganic Mulch include:

Stones such as pea gravel, river rock or gravel

Rubber chips

Planting tips

After the ground is prepared, you are ready to plant.

Dig a hole approximately twice the size of the root ball of the plant (or plant container) and fill it with water (all of the water won’t stay but it will soak the planting area).

Carefully soak the root ball of the plant.
Plant as deep as the soil line of the container the plant came in, leaving enough room for growth (read the labels).
Lightly pack the soil around the plant base, without heavy compaction.
Add 2.5 cm (1 inch) of water around the base of the new plant.
Spread 5 — 7.5 cm (2 — 3 inches) of mulch such as wood chips, over all exposed soil to reduce weeds and retain soil moisture. Do keep mulch away from trunks and stems to let them breathe.

The best time to plant is in the spring, after the danger of frost and before the hot weather sets in (generally late May to early June). Alternately, a good planting time is in the fall from mid-September to mid-October — especially for trees and shrubs. Dormant trees (after they shed their leaves) are easily transplanted any time before freeze-up.

Herbs and grasses

Many herbs have lovely flowers, are drought tolerant and thrive in average to poor soil. Mix herbs and annuals in one container or try a collection of herb-filled planters. Many herbs have pleasing foliage so once the flowers are spent you can enjoy the greenery — or snip a bit to add to your cooking or salads.

Alternatives to traditional gardens

Container planting

Container planting is a wonderful way to add colour and beauty to hardscaped areas — patios, decks, steps, walkways and balconies — around your property. Window boxes, hanging baskets and other planters filled with flowers are charming accents for any home, but as anyone who has gardened with containers knows, frequent watering is often required to keep plants healthy and blooming. By choosing from a large selection of water-efficient annuals, perennials, herbs, ornamental grasses and shrubs, you can create a stunning and unique display with your planters. Drought tolerant plants come in an array of shapes, sizes, colours, textures and growing habits — from climbing to trailing and everything in between.

For a dramatic statement, consider using ornamental grasses in your containers. Grouped or individually, these grasses add visual interest to any planter arrangement. Before purchasing ornamental grasses for your containers, be sure to check for their height at maturity — some grasses grow very tall — and select ones that suit the space where they’re to be located.

Depending on hardiness, most herbs and grasses can be kept indoors over winter or in a cold-frame — when purchasing, ask for instructions.

It seems everyone limits their choice for container plants to thirsty annuals like Impatiens, Tuberous Begonias and Fuchsias. Instead, try filling your baskets and pots with a few of the many water-efficient annuals, perennials, grasses and herbs for a dramatic and beautiful effect.

Try the following tips to reduce water use and keep your plants happy and healthy throughout the season:

Group planters close together so plants will help shade each other.
Use a watering can with a narrow spout or hose attachment to reduce spillage.
Where possible, set containers in a deep base and water from the bottom. This will encourage roots to move downward and away from the warmer, dryer surface soil.
Add shredded newspaper or sponge-like additives available from garden centres in the bottom of the container to retain moisture.
Line porous containers — terra-cotta and cement pots and fibre-lined wire baskets — with garbage bags to reduce moisture loss to evaporation or leakage.

If you are going to be away for several days, set pots in a shallow container of water and move them to a location that is shaded during the hottest part of the day.

Groundcovers

One of the easiest solutions to problem areas of landscapes — steep slopes, deep shade and wet soils — is planting "groundcovers" instead of flowering plants, trees or shrubs. There is an abundant selection of groundcovers that, once established, can bring the most barren landscape to life with eye-catching lush foliage and interesting textures.

Tip

For locations where little else will grow or access is difficult, plant one or more groundcovers and the area will be transformed in very little time.

Groundcovers spread quickly to cover large areas, are low maintenance once established and are easy on the pocketbook.
There are a wide variety of groundcovers including perennial plants, shrubs, evergreen trees, ornamental grasses, ferns and herbs.
Many groundcovers are drought tolerant and thrive in exposed, dry locations while others tolerate wet soils and deep shade.
Selecting the right groundcover is about matching a plant's needs to the site and soil conditions of the location to be planted.
Some groundcovers are drought tolerant and thrive in a hot and sunny location. Other groundcovers need loamy soil, in a naturally moist and shady location. Remember, selecting a groundcover suitable to the site conditions means minimal maintenance and irrigation is required once the plants are established. Select from one of the groundcovers listed in this section.

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