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Garden care

Create a water-efficient garden

Follow these steps

Soil preparation

Prepare the soil to provide nutrients and moisture to help plants grow.

  • Add compost, peat moss, or manure to enrich your soil
  • Mix the compost or other organic materials into the top 30 centimetres of soil

Plant selection

Choose drought resistant plants to conserve water use.

  • Group plants by their water and sun/shade requirements
  • Use grass only for well-travelled areas or as a backdrop for flowerbeds
  • Use water efficient irrigation techniques, such as soaker hoses for vegetables because they require more water

Plant

  • Dig an appropriately sized hole for plants
  • Add compost mixed with native soil to the bottom of the hole
  • Centre the plant in the hole and water, covering the roots to ensure adequate moisture at the time of planting
  • Cover the plant with soil matching the soil level of the neighbouring area. Create a ring around the plant and water

Mulch

Mulch helps control erosion, suppress weeds, retain moisture, control soil temperature and reduce disease transmission. Bark, wood chips, compost, grass clippings and crushed river rock can all be used as mulch material.

  • Spread the selected mulch in a layer about 10 cm deep over the garden

Irrigation

Proper irrigation techniques ensure that your garden receives enough water.

  • Use soaker hoses or a drip irrigation system to water once a week. This will reduce the amount of water lost to evaporation
  • Position sprinklers to avoid paved and hard surface areas
  • Take into account the amount of rainfall before watering. Leave a measuring container out in the garden to help assess how much rain falls each week
  • Water, if necessary, in the morning. Avoid watering in the afternoon or on windy days when water can be wasted to evaporation
  • Collect rainwater in a barrel for garden use
  • Reduce the amount of asphalt or concrete around the garden to reduce run off and allow the rain to soak into the ground

Native plants

Native plants are adapted to local climate, soil conditions and diseases. Since they have evolved surviving on rainfall alone, they are good choices for low maintenance, low water consumption gardens.

Check with your local nursery or garden supply store for more information on native plants such as the ones suggested below. Local sources of native plants include the Ferguson Forest Centre in Kemptville and the Oldfield Habitat Garden & Wildflower Nursery, as well as the Ottawa Field-Naturalists’ Club’s annual native plant sale at the Fletcher Wildlife Garden (Experimental Farm).

Make sure that the plants you choose are actually native to eastern Ontario, not just to North America in general. The City of Ottawa has a list of all known plant species occurring here, with notations on which ones are not native to our area. There are several organisations that provide great resources as well; for more information on native plants, please refer to the following:

Groundcovers

In areas that are not used much, grass can be replaced by one or more groundcovers. Many of the following species will thrive in shady areas, unlike most turf grasses.

  • Bearberry (white-pink flowers in early spring; red berries in summer) – Arctostaphylos uva-ursi
  • Bloodroot (beautiful white flowers in early spring) – Sanguinaria canadensis
  • Bunchberry (white flowers followed by red berries) – Cornus canadensis
  • Canada Mayflower (white flowers in spring) – Maianthemum canadense
  • Foamflower (clusters of white flowers in spring) – Tiarella cordifolia
  • Partridgeberry (very low-growing, evergreen with red berries) – Mitchella repens
  • Violets, including Sweet White, Canada, Northern White, Yellow or Common Blue – Viola blanda, V. canadensis, V. macloskeyi, V. pubescens or V. sororia
  • Wild Ginger (interesting flowers in spring) – Asarum canadense
  • Wild Strawberry (white flowers in late spring, edible berries in summer) – Fragaria virginiana
  • Wintergreen (low-growing, aromatic evergreen leaves and red berries) – Gaultheria procumbens

Wildflowers

Many commercially prepared wildflower seed mixes contain species that are not native to our area. Some mixes even include invasive species that should not be planted near natural areas!

  • Asters, such as Panicled, Calico, New England or Purple-stemmed – Symphyotrichum (formerly Aster) lanceolatum, S. lateriflorum, S. novae-angliae or S. puniceum
  • Blue Flag – Iris versicolor
  • Canada Anemone – Anemone canadensis
  • Cardinal Flower – Lobelia cardinalis
  • Goldenrods, including Tall, Canada, Zigzag, Early or Rough – Solidago altissima, S. canadensis, S. flexicaulis, S. juncea or S. rugosa
  • Spring-beauty – Claytonia caroliniana
  • Trilliums, including White or Red – Trillium grandiflorum or T. erectum
  • Wild Columbine – Aquilegia canadensis

Shrubs

  • Canada Yew (evergreen) – Taxus canadensis
  • Chokeberry – Aronia melanocarpa (also known as Photinia melanocarpa)
  • Common Juniper (evergreen) – Juniperus communis
  • Elderberry, either Common or Red – Sambucus canadensis or S. pubens (also known as S. racemosa ssp. pubens)
  • Maple-leaf Viburnum – Viburnum acerifolium
  • Nannyberry – Viburnum lentago
  • Northern Bush-honeysuckle – Diervilla lonicera
  • Purple-flowered Raspberry (large, showy flowers and leaves) – Rubus odoratus
  • Staghorn Sumac (large shrub/small tree; spreads by roots) – Rhus typhina
  • Winterberry (bright red berries in fall and winter) – Ilex verticillata

Trees (small)

  • Alternate-leaved Dogwood – Cornus alternifolia
  • Blue-beech – Carpinus caroliniana
  • Hawthorn – Crataegus chrysocarpa, C. flabellata or C. submollis
  • Pin Cherry – Prunus pensylvanica
  • Maple, either Mountain or Striped – Acer spicatum or A. pensylvanicum
  • Serviceberry – Amelanchier arborea
  • White Cedar (evergreen) – Thuja occidentalis

Trees (large)

  • American Beech – Fagus grandifolia
  • Balsam Fir (evergreen) – Abies balsamea
  • Birch, either White or Yellow – Betula papyrifera or B. alleghaniensis
  • Bitternut Hickory – Carya cordiformis
  • Black Cherry – Prunus serotina
  • Maple, either Red, Silver, United (hybrid) or Sugar – Acer rubrum, A. saccharinum, A. x freemanii or A. saccharum
  • Oak, either Red or Bur – Quercus rubra or Q. macrocarpa
  • Tamarack – Larix laricina
  • White Pine (evergreen) – Pinus strobus
  • White Spruce (evergreen) – Picea glauca

Ten low-maintenance perennials

The plants suggested here are hardy, easy to grow, beautiful and very rarely have insect or disease problems. However, they are not native to the Ottawa area. Enjoy them in your garden, but please do not let them invade our natural areas! Please visit our native plants page for other options.

Achillea filipendulina (Asteraceae or Compositae)

Fern-leaf Yarrow

Achillea filipendulin

Achillea filipendulina

These clump-forming Yarrows bloom in early summer. The leaves are fern-like and aromatic. The flowers form flat-topped heads normally in shades of yellow though there are some cultivars that are pink, peach or red. Cultivars vary in height from a few inches to five feet tall and are used in perennial borders and meadows. After they bloom, cut the stems down to the ground.

  • Grow them in a sunny spot in evenly moist, fertile soil.
  • They do not need fertilizing, instead mulch annually with compost to maintain soil moisture and fertility.
  • They may get powdery mildew disease (August usually) when grown in poor, dry soil.
  • Divide the clumps every few years otherwise they become too large

Artemisia sp. (Asteraceae or Compositae)

Artemisia, Wormwood, Silver-Lady Lavender, Silver or White Sage

Artemisia sp.

Artemisia sp.

Artemisias are easy to grow in a hot, dry, sandy location and like many heat and drought-tolerant plants most have silver-grey foliage (fernlike, finely cut, silvery-white leaves with a hairy coating covering the leaf surface). The small, inconspicuous flowers are wind pollinated. There are many cultivars that differ in height, intensity of silver colour and leaf form. There are many species in cultivation, including Absinth, and the culinary herb Tarragon. Artemisia schmidtiana 'Silver Mound' is the most popular one used in Ottawa, it forms a 30 cm (12") x 30 - 45cm (12-18") mound, used as an edging plant in the border.

The leaf colour helps to tie the border together, adds an attractive contrast to dark green plants and, compliments pink, red, bronze and blue plants in the garden. They are also used in large mass plantings

  • Needs full sun to keep the colour strong and the growth sturdy.
  • Grows readily in any soil that is not wet, but prefers a dry, sandy, soil.
  • Should not be fertilized as plants become more greenish and spread too rapidly.
  • Regular division in spring or early September helps keep the spreading plants in check.
  • Cut 'Silver mound' back to 5cm (2") when it begins to bloom in mid to late June otherwise it flops open.

Astilbe (Saxifragaceae)

Astilbe

Astilbe

Astilbe

Astilbes originate in China and Japan but there has been a great deal of hybridization since the 1920's. Astilbes are considered the Queen of Flowers for moist shade, they are very low maintenance and free from problems. They produce dense, weed-proof groundcover and attractive flowers. Spike-like or soft, feathery, plume flowers rise above lacy dark green leaves; the many cultivars provide a long blooming time. Choose plants by size, flower colour and shape, and blooming time.

A. x arendsii: blooms from June- August, heights range from 55 - 100cm ( 22" - 3') flowers are red, pink, cream, white or lilac,

A. chinesis: this ground covering Astilbe blooms August - September, height is 30 cm (12"), flowers are pink, salmon, lavender, purple, and magenta.

A. glaberrima saxatilis: a rock garden plant at 10 - 20 cm (4 - 8"), blooming in July - August, shell-pink flowers

  • Partial shade in ordinary moist soil - full sun in very moist soil
  • Fertile, evenly and continuously moist soil
  • Top-dress with well-rotted manure/compost (2.5 - 5 cm) every fall
  • Divides easily in spring, as the new growth appears, plants can be lifted and divided or moved even in flower (if they are well watered)

Echinacea purpurea (Asteraceae or Compositae)

Purple Coneflower

Echinacea purpurea

Echinacea purpurea

This plant, native to the eastern United States, grows in grassy areas and open woodland meadows. The herbal remedy Echinacea comes from E. angustifolia. Flowers bloom above the rough, course leaves, which form a dense clump. The daisy flower head has a prominent hard, bristly, brown cone surrounded by drooping purple-pink petals. Echinaceas bloom from July - September. Purple Coneflower is an important plant for the summer border and for naturalizing meadows and wild-gardens. It grows to 75 - 120 cm (30 - 48 ") tall.

Rudbeckia, Black-eyed Susans, Cone-flower or Gloriosa Daisy, are similar to Echinacea in form, and requirements except that the bloom is bright yellow instead of purple.

  • Full sun
  • Ordinary well-drained garden soil, drought-tolerant
  • No fertilizer needed
  • Staking is needed in very rich, moist soils
  • Deadhead old flowers, seed heads can be use in dry floral arrangements.
  • Divide the clumps in spring. Seeds germinate easily and grow quickly.

Euphorbia polychroma (or E. epithymoides) (Crassulaceae)

Cushion Spurge

Euphorbia polychroma

Euphorbia polychroma

It is in the same family as Poinsettia and in fact it is the coloured bracts that give the plant its bright greenish-yellow colour in late spring (in Ottawa when the tulips bloom). In the spring it grows rapidly into a neat mound about 30 - 45 cm (12 - 18"), high having smooth, 5 cm (2") long leaves. The stems grow a little longer after the flowers fade forming a green mound, which turns red in the fall. All spurges produce a milky sap from broken leaves or stems, which may be irritating to the skin. Interplant it with spring flowering bulbs and perennials, at the base of a rock garden or with shrubs. Other spurges grown in Ottawa are:

E. griffithii: 50 - 90 cm (20 - 36") flame-orange bracts turn red in fall.

E.myrsinites: a succulent, prostrate, 15 - 20 cm (6 - 8"), blue leafed, evergreen rock garden plant with yellow coloured bracts in spring.

  • Full sun
  • Well-drained to dry soil, very drought-tolerant
  • Avoid fertilizing otherwise plants become floppy
  • Careful division in early spring (try to avoid damaging the fleshy roots)

Ornamental Grasses (Poaceae or Gramineae)

Ornamental Grasses

Ornamental Grasses

The grass family contains about 6,000 species. The cereal crops are Grasses. They are highly evolved, wind-pollinated plants used for their long, thin foliage (may be brightly coloured) and upright form. The look and sound when they blow in the wind is very appealing. In the late summer they have feathery flowers at the top of the stems, which remain for months. Grasses range from 15 cm - 4 m (6" - 4 yd.) tall. Depending on size they can be specimen plants, container plants, groundcovers, mass planted or accents in the garden. Control their width to about 2/3 height. Clump forming grasses are not invasive. Grasses create a casual garden style, having full sensory impact in late summer and fall. .

  • Full sun
  • Ordinary garden soil. Most species are tolerant of dry soil but some are adapted to wet soil.
  • Does not need fertilizer
  • If it is grown for winter effect, cut them down in very early spring before new growth starts. Cut other grasses in late fall.
  • Best to divide in the spring just as the new growth starts, but many grasses can be divided in early September.
  • Hardy to Zones 3 - 5 (cultivar dependant)
Invasive Grasses- Do not plant
  • Arundo donax: Giant Reed
  • Bromus inermis 'Skinner's Gold"
  • Elymus racemosus (Leymus): Lime Grass
  • Glyceria maxima 'Variegata": Manna Grass
  • Miscanthus sacchariflorus 'Robustus': Giant Silver Grass
  • Phalaris arundinacea: Ribbon Grass
  • Spartina pectinata 'Aureomarginata': Cord Grass
North American Grasses
  • Andropogon gerardii, A. scoparius: Blue Stem Grass (rare natives in the Ottawa area)
  • Bouteloua gracilis: Mosquito Grass
  • Carex grayii, C. muskingumensis: Sedge (C. grayii is native to Ottawa)
  • Chasmanthium latifolium: Sea Oats
  • Panicum virgatum: Switch Grass
  • Stipa tenuissima: Feather Grass
Showy Seed Heads
  • Calamagrostis: Feather Reed Grass
  • Chasmanthium: Sea Oats
  • Deschampsia: Tufted Hair Grass
  • Erianthus ( Saccharum): Plume Grass
  • Miscanthus: Miscanthus, Eulalia
  • Moliina: Moor Grass
  • Panicum: Switch Grass
  • Pennisetum: Fountain Grass
  • Stipa: Feather Grass
Drought-Tolerant Grasses
  • Andropogon: Blue Stem Grass
  • Bouteloua: Mosquito Grass
  • Erianthus: Plume Grass
  • Festuca: Fescue
  • Phalaris: Ribbon Grass
Dry, well-drained Soil
  • Elymus racemosus
  • Festuca: Fescue
  • Helictotrichon: Blue Oat Grass
  • Pennisetum orientale: Oriental Fountain Grass
  • Sesleria caerulea: Blue Moor Grass
  • Stipa: Feather Grass
Damp soil
  • Acorus: Sweet Flag
  • Carex: Sedge
  • Chasmanthium: Sea Oats
  • Descampsia: Tufted Hair Grass
  • Glyceria: Manna Grass
  • Luzula: Wood Rush
  • Milium: Golden Grass
  • Miscanthus: Miscanthus
  • Molinia: Moor Grass
  • Panicum: Switch Grass
  • Pennisetum: Fountain Grass
  • Phalaris: Ribbon Grass
  • Spartina: Cord Grass

Hemerocallis hybrids (Liliaceae)

Daylily

Hemerocallis hybrids

Hemerocallis hybrids

Daylilies have been popular since the 1930's. In the spring, grass-like leaves emerge forming a clump. The leaves have a keel down the length in the middle. The leaves range in length from 30 - 60 cm (1 to 2') and are 2.5 cm (1") wide. Open, lily-like flowers bloom from late May - late August, with the peak period in July. The flowers open one at a time from the top of a leafless stem, each lasting one day. Daylilies come in a wide range of colours: yellow, orange, peach, apricot, and rust. They are grown in the border, as a groundcover, mass planted in hard to look after areas, and in large containers. The dense foliage will smother many weeds.

  • Full sun, (some pale colours prefer afternoon shade).
  • Well-drained, ordinary soil. High organic content recommended. Tolerant of drought and neglect.
  • No fertilizing needed
  • Divide anytime, best in early spring or early fall
  • Cut back the flower stems after blooming
  • Cut foliage down in the fall

Ligularia sp. (Asteraceae or Compositae)

Ligularia or Golden Ray

Ligularia sp.

Ligularia sp.

Ligularia is a long-lived, easy-to-care-for plant when grown in cool, moist, fertile soil. Large glossy leaves mound over the soil at the base of the plant. They bloom yellow/orange daisy flowers singly or on spikes, in late summer - early fall. These tall, dramatic plants can be 3 feet across, more in rich soil. Large leafed plants create a bold tropical effect. Plant them as accents, specimens, beside ponds and streams. They always attract attention!

L. dentate:

'Desdemona': Leaves dark purple underneath, bright orange daisy-like flowers.
Grows to 90 - 120(3 - 4').
'Othello': Leaves brownish, blooms slightly earlier than 'Desdemona'.
Grows to 90 - 120 cm (3 - 4').

L. stenocephala:

Leaves deeply toothed, small yellow flowers on narrow, glossy purple-black,
upright flower stems.
Grows to 120 - 180 cm (4 - 6').
Cultivars include 'The Rocket' and 'Sungold'

L. wilsoniana:

Tall spikes of yellow flowers in mid-summer. Grows to 150 - 180 cm (5 - 6')

  • Full sun in wet soil, light shade is better in hot areas where the soil is not wet.
  • Best in a rich, moist soil, but will grow quite well in regular soil
  • No need for fertilizing.
  • Spring division when needed (seldom). Plants take a couple of years to establish

Paeonia hybrids (Paeoniaceae)

Garden Peony

Paeonia hybrids

Paeonia hybrids

Paeonia hybrids

Paeonia hybrids

Peonies have been cultivated in China for centuries. In the late 1700's they were introduced to the rest of the world and have never lost their popularity. They are beautiful, easy to grow and very long lived. Peonies are a focal point in the border when they bloom, and after they remain an attractive shrub-like mounding plant. The Bomb and Double types are the most commonly used Peonies but because the flower heads are very heavy they need staking. Japanese, Anemone and Semi-double types are easier to care for in the garden because the flowers stay up without staking.

Peonies form large, bushy, mounding plants, 75 - 100 cm (30 to 40") x 100cm (3'), with shiny, divided leaves that change colour in the fall to yellow or red. Single flowers form at the top of the stems, (above the mounded leaves) with other buds growing below but usually they do not open. Peonies come in pink, red and white and bloom from late May to mid-June. Ants eat the sticky material on the bud, but this does not help the flowers to open.

Hot humid weather increases the possibility of Botrytis blight. Cut out the affected leaves and stems (they become brown and die back). This is not a common problem and is a sign that the plants are not growing in proper conditions

  • Full sun or light shade.
  • Deep, fertile, well-drained loamy soil
  • An application of sulphate of potash in early spring will help keep the flower stems stronger.
  • Divide the woody crown, (10 - 15 years) in early fall (late August early September in Ottawa). Pieces should have 2 or 3 buds (pips, or eyes) and a good size piece of root to do well. When planting new plants it is important to place the buds at the same depth in the soil as they were at before. Deeper planting will delay flowering. It may take 2 or 3 growing seasons for peonies to develop and flower well again.
  • Deadhead flowers to create a neat dome shaped plant that will be a background to other flowers.
  • Staking is often needed for double cultivars. It should be done before flowering in early spring otherwise the stems may fall and break
  • Cut the stems down to a few cm in late fall and top-dress with 2.5 - 5 cm (1 - 2") of well-rotted compost or manure.

Sedum sp. (Crassulaceae)

Stonecrop

Sedum sp.

Sedum sp.

Sedums are succulent plants adapted to dry conditions. The thick fleshy leaves store water. Low mat forming species often have a wide variety of leaf and flower colour, and are excellent for rock gardens, or groundcovers even on hot, dry slopes. Taller species have beautiful fall colour, attract pollinators and give wonderful colour in borders. All sedums are nice in containers.

S. acre: 8 cm (3"), yellow leaves in spring, turning green, followed by yellow flowers in late summer
S. album: 10 cm (4"), green leaves turn red-maroon in fall, flowers either white or pink
S. anacampseros: 15 - 25 cm (6 - 10"), round blue leaves, purple flowers in late summer
S. cauticola: 10 cm (4"), blue leaves, pink flowers in late summer-late fall
S. cyaneum: 10 cm (4"), blue leaves, rose-pink flowers starting in early fall
S. divergens: 10-15 cm (4-6") globe shaped green leaves, yellow flowers in summer. Native plant.
S. ewersii: 15 cm (6") blue round leaves, rose pink flowers in late summer
S. kamtschaticum: 15 cm (6") Moist soil. Scalloped leaves, yellow or gold flowers in summer
S. oreganum: 15 cm (6") Thick leaves, yellow flower. Native plant
S. reflexum: 15 cm (6") Blue needle-like leaves, yellow flowers.
S. sieboldii: 15 - 20 cm (6 - 8"),blue scalloped leaves, pink flowers in late fall.
S. spathulifolium: 10 cm (4"), rosette of fleshy leaves, yellow flowers in summer.
S. spurium: 15 cm (6") mat forming, often variegated leaves, with pink, red or white flowers.
S. telephium x spectabile 'Herbstfreude': 45-60 cm (18-24") This is the most popular border sedum. Autumn Joy sedum flowers are small but are in large flat-topped heads above the foliage, they start off cream-green and gradually turn from pink, to a deep, bronzy-mahogany red from September - October.

  • Full sun, (partial shade for some cultivars)
  • Well-drained, ordinary soil. Very drought-tolerant
  • No fertilizer needed
  • Divide anytime, best in early spring. Very large plants that need staking should be divided
  • Cutting back stems in spring if you like to see the flower heads poke through the snow