Definition of a Perennial

Perennials are herbaceous (non-woody) plants that die to the ground each winter and grow anew from the roots each spring. Perennials are relatively easy plants to grow, given the right location and proper care. Perennials can be used in beds, borders, cutting gardens, at water’s edge, rock gardens, naturalized woodlands or meadow plantings.

Choosing the Right Plant

You need the right plant for the right situation. The most important factors when choosing a plant are the amount of sunlight the location receives and the soil condition. More than six hours of sunlight is considered full sun.  If you get less than three hours of sun, then choose shade plants.

Preparing the Soil

Preparing the soil in the bed is the first important step towards getting a plant off to a good start. Most perennials grow best in well-drained soils. If your soil is sand or clay based, the addition of organic matter such as peat moss or compost can be very helpful.

Container grown perennials can be planted any time during the growing season. If you can, choose an overcast day for planting – hot sun will stress plants. If you can’t plant right away, don’t let containers dry out. Keep them in the shade and well watered. Circulation of air reduces the risk of mold and mildew, so leave space between plants. Set the plant in the ground at the same level it was in the container. Water plants thoroughly. All late season plantings should be mulched for their first winter. This protects the plants from “heaving”, which pushed plants above ground and lead to their death.

Watering

Watering early in the day allows foliage to dry before dark and reduces diseases.  Newly planted perennials need more attention than established plants. Keep an eye on them over the first few weeks and make sure they stay watered. Do not fertilize them right away. Plants will not need additional nutrients until they are growing well.

Perennial Plants for Hummingbirds

Perennial Plants for Butterflies

Agastache                           Lupinus Asclepias (Milkweed)      Echinacea                   
Aquilegia Lychnis Asters Eupatorium
Delphiniums Monarda Autumn Joy Sedum Lavandula
Dianthus Penstemon Baptisia Liatrus
Foxglove Phlox Paniculata Buddleia Lychnis
Hemerocallis Salvia – Purple Rain Caryopteris Penstemon
Heuchera Scabiosa Centranthus Rudbeckia
Honeysuckle Trumpet Vine Ceratostigma Saponaria
Iris Yucca Dianthus Stokesia

Perennials that do well in moist areas

Perennials that do well in dry areas

Astilibe    Hemerocallis Achillea Russian Sage
Aruncus Iris Ensata Asclepsia Yarrow
Bergenia Lobelia Cardinals Amsonia
Chelone Ligularia Armeria
Cimicifuga Lythrum Artemesia
Convallama Physostegia Coreopsis Threadleaf
Eupatorium Primula Fla
Ferns Rodgersi Guara
Filipendula Lambs Ear

(Courtesy of Landscape Ontario)

A perennial is a herbaceous (soft and fleshy) plant that thrives for three or more years. Perennials come in a variety of sizes, shapes and colours and can bloom from early April until late October. For these reasons, they are fast becoming more popular. Perennials are one of the easiest plants to grow. Sun or shade, clay or loam, there is a perennial for almost all of your garden needs.

Planning

Planning is an essential part of having a perennial garden. Gardens that are not planned usually have no direction and often are a jumble of colour.

When planning a garden, many factors determine the shape of your garden; from which angle you will view your garden; whether the garden will be informal or formal, and the type of planting (bed or border) you want.

Once the beds and type of garden are decided then it’s time to choose the types of plants you need. Some factors to consider are light and soil requirements, plant height, time and length of flower, and flower colour. Other factors may be plant fragrance, suitability of plants for fresh cut or dried flowers, and the plants. form and texture.

Once all the factors are considered, then it is time to lay out your garden on paper. From a detailed plan, one can see how the garden will look.

Bed Preparation

Bed preparation is one of the most important aspects in having a successful perennial garden. First, the bed should be dug to a depth of one foot. Next, one should decide what type of soil you have.

For clay soils, 10 to 15 cm of sand and peat moss should be added so the soil can drain properly. Adding gypsum (11 kg per 100 sq. ft.) helps break down the clay. If necessary, garden sulphur can be added to lower the acidity of the soil.

For sandy soils, add 10 to 15 cm of organic material (peat moss, manure, compost) to the soil to hold the moisture in the ground. When adding an organic material, also add a high-nitrogen fertilizer (urea 33-0-0) to help the material break down.

For peaty soils, add horticultural lime to raise the alkalinity of the soil, if necessary.

Finally, an all purpose fertilizer should be worked into the soil. A top dressing of mulch will keep the moisture in and the weeds out.

Planting

Planting perennials is a simple task, but the importance should not be overlooked. There are two stages (dormant and active) in which perennials can be planted. Dormant plants are usually planted in the fall and active plants in the spring and summer.

Planting is a simple task. With a trowel, dig a hole slightly larger than the container in which the plant came. Place the plant in the hole at the same depth as the container (Remember to remove the container). Once in, firm the soil around the plants. Plants should then be watered in with a transplant fertilizer (high in phosphorous).

Care

Perennials are relatively easy to care for, but they are not maintenance free. Watering, fertilizing, mulching and dividing are some of the tasks involved with the care of perennials.

Fertilizing should be done three times per year (spring, summer and fall) with an all-purpose granular fertilizer. Some perennials need more nutrients during the year and a water soluble general fertilizer should be applied. Watering of newly planted perennials should be done on a regular basis. More established plants should be watered only when there is a dry spell.

Bark, cocoa bean, needle and leaf mulches are some of the mulches used to cover perennials for the winter. Mulching can increase the survival rate of plants through the winter. Mulches provide a weed barrier as well as keeping moisture in the ground.

The dividing of plants is done for three reasons: to control size, to rejuvenate plants, and for the propagation of plants. Dividing is done in the spring and summer. When dividing in the spring, just divide those varieties that bloom in the summer and fall. Only those varieties which bloom in the spring should be divided in the summer.

A perennial garden can provide the homeowner with much enjoyment. Cut and dried flowers, perfumed scents and blooms from April to October are some of the rewards of growing perennials. With a little effort, one can enjoy a garden that blooms and grows for many years.

Perennials for different purposes:

Perennial Plants for Hummingbirds

Perennial Plants for Butterflies

Agastache  Aquilegia Autumn Joy Sedum Asters
Delphiniums Dianthus Asclepsia (Milkweed) Baptisia
Foxglove Hemerocallis Centranthus Caryopteris
Heuchera Honeysuckle Buddleia Ceratostigma
Iris Lupinus Dianthus Echinacea
Lychnis Monarda Eupatorium Lavandula
Penstemon Phlox paniculata Liatrus Lychnis
Salvia – Purple Rain Scabiosa Penstemon Rudbeckia
Trumpet Vine Yucca Saponaria Stokesia

Perennials that do well in moist areas

Perennials that do well in dry areas

Astilibe               Hemerocallis Achillea                 Fla
Aruncus Iris Ensata Asclepsia Guara
Bergenia Lobelia Cardinals Amsonia LambsEar
Chelone Ligularia Armeria Russian Sage
Cimicifuga Lythrum Artemesia Yarrow
Convallama Physostegia Coreopsis Threadleaf
Eupatorium Primula
Ferns Rodgersi
Filipendula
(Courtesy of Landscape Ontario)

Tall Bearded Iris and Peonies, flowering May to June

Oriental Poppy and Delphiniums, flowering in June and July

Dayliliy, flowering in July and August

Tall Phlox, flowering in August and September

Delphiniums, re-flowering in September

These six essential perennials are plants of size and substance. They will be the backbone of your perennial garden. With the wide choice of cultivars available in each of these six basic plants, any colour scheme is possible. Your perennial garden could consist totally of these few basic perennials, but if space permits, it is so easy with the many hundreds of perennials available to fill in around them. Not only would this create an increasingly lush garden, you could begin the flower display earlier than the show of Iris and Peony, and extend it later in the fall.

Tall Bearded Iris

Unlike the common wild Iris or Flag that flourish in wet, swampy places, the tall Bearded Iris are dry-land plants that need a sunny location and well-drained soil. In planting, the rhizomes should be set just below the surface of the soil. The growing point is at one end of the rhizomes. To obtain a good size clump quickly, the rhizomes may be set together so that they radiate out from the centre. After flowering, the flower stems should be cut back but the leaves must be left to manufacture food for the plant until fall. Before the onset of winter the foliage should be cut back to within a few inches of the ground and all dead leaves removed. Since Iris are very hardy, no winter mulch is necessary; it is best to keep them free of all material which might tend to hold moisture around the  rhizomes and induce rotting.

Peonies

Peonies are long-lived plants that will continue to flower for generations. They need never be disturbed, although if moving them becomes necessary, the large clump should be reduced to sections with three to five eyes. A large clump moved whole would most likely cease flowering. Plant peonies no more than two inches deep, with .eyes. into the soil. They will not flower if planted any deeper.

Daylilys – Hemerocallis hybrids

Daylilies are the heart of the mid-summer perennial garden. Daylilies flower non-stop through the heat of July and August (Stella d’Oro continues through September). They have a fabulous colour range. Apricot, Bronze, Crimson, Gold, Lemon, Mahogany, Maroon, Orange, Pink, Purple, Red, Violet and Yellow. They are tough, hardy and reliable. Each lily-like flower lasts only a day but they are continuously in bloom over many weeks. The leaves look like arching, pointed straps. Daylilies are large, wide plants that need at least three feet of space.

Oriental Poppies

Oriental Poppies set the June garden afire with a blaze of colour. They need only well- drained soil in full sun or partial shade. To plant Poppies, set the root straight down into a planting hole, deep enough that the crown is covered by at least three inches of soil. The plant foliage is downy with fine hairs. It appears prickly but is actually soft to the touch. After June’s giant blooms have faded, the flowerheads should be removed and not allowed to form seed. The foliage then dies down and can leave a void in the border. Many gardeners plant Day Lilies or Baby’s Breath nearby to fill the space. In September, the Poppies will grow a new basal rosette of leaves. Mulch around the plant for winter protection but do not cover the rosette.

Delphiniums

These stately and spectacular tall plants are essential to any perennial border. They need rich, well-drained soil; incorporate well-composted manure in the planting mix and add a mulch or top dressing of manure annually. Delphiniums are best planted in groups of perhaps three of a kind. By cutting out all but three of the best shoots at approximately 15 cm in height, these delphiniums will produce fatter, stronger and better flowers on the remaining spikes. Grown like this, the plants are strong enough not to require staking.

However, unless planted in a spot protected from wind, staking will still be required if they are to be saved from high winds that accompany our all too frequent summer thunderstorms. Delphiniums exhibit a central bunch of petaloids, a flower within a flower, commonly referred to as a  bee. The black “bee” in ‘Black Knight’ intensifies the already dark blue of the flower and makes it appear bluer. The white “bee” on the white ‘Galahad’ turns the flower into a “double white”. After the main flowering period has passed about mid-July, cut some stems to the first leaves and others right to the ground. The plant will then re-bloom in August and September. While flowering is not as spectacular as in June, it is still attractive and makes a welcome addition to the fall garden.

Tall Phlox (Summer Phlox)

Tall Phlox are invaluable for continuing the summer-long display of colour in the perennial border. Use a lavish hand with these brilliant flowers, choose a few kinds and plant them in irregular drifts for a magnificent display. There are a variety of colours from which to choose, many with a contrasting eye. Choose from all the pink ranges (peach pink to salmon and rose), pure white to whites with a coloured eye, orange red to scarlet, and mauve to mulberry purple.

(Courtesy of Landscape Ontario)

Having fresh flowers in your home every day is one of life’s many pleasures. With even a small perennial garden you can enjoy fresh flowers from spring to fall. To be able to step into your own garden, make your selection of flowers in bloom and arrange them in a water holding container is itself a pleasant and satisfying action.

Many plants that grow from bulbs, (Tulips, Daffodils and Hyacinth), provide beautiful cut flowers through April and May. The dying foliage of bulbous plants is masked by the foliage of other emerging perennials.

Yarrow (Achillea) – Available in yellow, white, pink, red and orange. The flowers are long lasting and the foliage is fine and feathery. The cultivar ‘Moonshine’ has lemon yellow flowers and silvery foliage.

Lady’s Mantle (Alchemilla) – A flower arranger’s favourite. Unusual chartreuse flowers and attractive foliage. They last a long time in water.

Columbine (Aquilegia) – Beautiful June blooming plants that come in many colours and colour combinations. Their unique spurred flowers can better be viewed close up. An excellent cut flower.

Artemisia – ‘Silver King,’ ‘Silver Queen’ and other varieties provide silver foliage that combine well with strong colours like purple or deep blue.

Astilbe – The arendsii hybrids that bloom from late May through June, have feathery plumes of pink, red or white flowers and highly attractive foliage. In many varieties, the spring leaves are quite red. Astilbe tacqueti superba flowers in July.

Chrysanthemum A large family of plants that provides many good cut flowers including Shasta Daisy which have single or double white blooms. Pyrethrum provides pinks and reds and is known as the Painted Daisy. Hardy “Mums” bloom from August to October and come in many colours.

Leopard’s Bane (Doronicum) – Bright yellow Daisy that combines well with bright red Tulips in spring.

Blanket Flower (Gaillardia) – Wonderful border perennials that flower all summer and are good cut flowers. Daisy-like flowers in yellow, red, mahogany and twotone combinations.

Baby’s Breath (Gypsophila) – Very useful filler in flower arrangements. Airy clusters of tiny pink or white blooms available in single or double forms.

Iris Dwarf – Iris bloom in spring followed by the tall Bearded Iris in late May and early June. Flowering next are Siberian, Japanese and Flag Iris. All have sword-like foliage and all are good as cut flowers.

Lilies – Species Lilies and Asiatic hybrids are beautiful flowers that work well in arrangements. Grown from hardy bulbs that can be planted in spring or fall.

Bee Balm (Monarda) – Available in white, red, pink, purple in ‘Panorama Mix’. Named varieties are ‘Cambridge Scarlet’, ‘Croftway Pink’ and ‘Blue Stocking”.

Peony – Many varieties are available both double and single in red, pink or white. Bloom time is from late May through June and the handsome foliage can provide greenery for later floral arrangements. DO NOT TAKE BLOOMS UNTIL YOUR PEONY IS AT LEAST THREE YEARS OLD.

Phlox (Phlox paniculata) – Summer Phlox or Tall Phlox have rich vibrant colours of white, pink, red and orange. Some varieties are bicolour with a contrasting ‘eye’. Very long bloom time from midsummer to fall.

Our alphabet of some favorite cut flowers ends with Salvia, Scabiosa and Veronica.The tall forms of Salvia are long lasting when cut. Scabiosa is called the Pincushion Flower and are usually blue, but white is also available. The tall spikes of Veronica are invaluable to the flower arranger. Pink, white and deep blue colours are available.

(Courtesy of Landscape Ontario)

One of the most common problems with shade in the garden, is the lack of it. In a new home, in a new subdivision, where can you grow lush leafy ferns, Astilbes and Hosta? There are so many plants that actually like shade. If you can create a garden in the shaded north side of your home, then you can enjoy a broad range of plants that thrive in shade.

ALL SHADE IS NOT THE SAME

Part Sun – Part Shade

At our latitude in summer, even the north side of the house gets sun. Rising in the far north-east in the morning, it catches the north side and again from the northwest as it sets. Plants on the east and west side get at least six hours of sun in the summer, sufficient for all plants except the true sun worshippers.

Open Shade

On the north side of the house, but open to the sky. Plants listed for light shade will do well.

Light Shade or Filtered Sunlight

Dappled shade; light or shadow move with the sun, like under a Locust or Birch. Lawn grass does well and so do most plants. Not shady enough for true shade lovers.

Medium Shade

The north side of the house, further obstructed by overhead branches. A shade tolerant lawn grass will still grow and now we can plant Astilbe and Hosta.

Deep Shade

(In the plant list, those for deep shade are indicated “*”)

Permanent year-round shade from buildings and large evergreens and shade trees. Usually found in the older residential areas. Grass will not grow well, but ferns will.

Dry Shade and Moist Shade

Deep shade is often moist since it does not receive the sun’s heat, but it can be dry under large trees that take all available moisture. There are very many plants for moist shade; dry shade is more difficult but the problem can be overcome by watering and mulching. A good perennial for dry shade is Barrenwort (Epimedium).

All shade is not the same. Deep shade is usually found in older gardens where trees are mature. In deep shade, the soil will usually be cool and moist – perfect conditions for Ferns and Hosta.

The large-leaved Hosta are luxurious in shade, some with glossy, dark green foliage, others are variegated green and white or green and gold. They all have attractive lily-like flowers mostly in shades of blue. One very nice variety is Royal Standard, with dark green leaves and fragrant white flowers.

Ferns are easy-to-grow, maintenance-free plants that mostly need or prefer cool, moist shade. As ferns become popular, an increasing number of varieties are appearing at garden centres. Ostrich Fern, Lady Fern and Sensitive Fern have long been favourites. Now available is Japanese Painted Fern, with blue-gray fronds, and colourful Autumn Fern with young coppery foliage. The Christmas Fern and Holly Ferns are evergreen.

Astilbe are the most beautiful plants for shade with their gorgeous plumes of red, pink or white flowers in June and very attractive spring foliage that remains green and handsome all summer . as long as the soil is moist.

Hosta, Ferns and colourful Astilbes will make a very attractive show in combination and are long-lived perennials for a garden in the shade.

Perennials for light shade or part day sun

(Those that take deep shade are marked with “*”) 

Aconitum Filipendula Obedient Plant
Anchusa Foxglove* Oriental Poppy
Arabis Garlic Chives Peony
Astilbe* Gas Plant Perennial Geraniums
Balloon Flower Geum Planted Daisy
Bergenia* Globe Thistle Primrose
Bethelehem Sage* Goatsbeard Purple Coneflower
Bleeding Heart Gold Moss Purple Loosestrife
Brunnera Gold Star Saxifrage*
Carpathian Harebell and other Campanula Gooseneck and Yellow Loosestrife Shasta Daisy
Cardinal Flower Hosta* Siberian Iris
Chives Jacob’s Ladder Solomon’s Seal*
Christmas Rose Japanese Anemone Spiderwort*
Chrysanthemum Leopard’s Bane Tall Phlox
Cimicifuga Lupines Trillium
Columbines Macleaya Trollius
Coral Bells Marsh Marigold Veronica
Creeping Jenny (Lysimachia nummularia)* Meadowrue Viola
Day Lily Monarda (Bergamot) Virginia Bluebells*
Feverfew Nepeta

 

Perennial ground cover for shade 

Ajuga Duchesnea* Hall’s Honeysuckle Sedge
All ferns* English Ivy Lily-of-the-Valley* Virginia Creeper
Cotoneaster Epimedium* Ornamental grasses Wild Ginger
Creeping Potentilla Euonymus Pachysandra* Wintergreen*
Crown Vetch Goutweed* Periwinkle