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Broad-leaved SedgeKeep your shade garden green all year with this fun little sedge that stays blueish-green over the winter!

Broad-Leaved Sedge (Carex platyphylla) is truly an undervalued sedge that is ideal for use in perennial/mixed boarders.  Carex platyphylla forms in clumps with a frosty blue colour that spreads slowly to form a beautifully textured groundcover that thrives in moist or average soils.  This species will even perform well in dry shade once it is established.  Other common names for this species include Blue Sedge and Silver Sedge.

Carex platyphylla is excellent to use for erosion control, winter interest, and are appropriate for deer resistant and low maintenance plantings, or rock gardens.  Other native plants that complement Carex platyphylla include:

In the Spring, be sure to prune back old leaves to make way for greenish, white, scaly flower spikes that are displayed above the foliage.


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February days can have you feeling dull and grey.  Luckily, there are a number of great native plants that can offer you a splash of colour to help cure your winter blahs.  Here are a few of our favourites:

  1. Carex platyphylla – BlBlue Sedgeue Sedge

Keep your shade garden green all year with this fun little sedge. It forms low mounds of bluish green leaves that over-winter, followed by a flush of tiny yellow florets, and bright turquois new leaves in the early spring. Best in dry-medium shade/part shade

  1. Winterberry HollyIlex verticillata – Winterberry Holly

Holly will liven up your winter garden, feeding birds, and adding a burst of red while the berries last. A mature holly can be selectively pruned to provide berry branches to make your own festive decorations!

  1. American SycamorePlatanus occidentalis – American Sycamore

American Sycamore is a cousin of the exotic hybrid London Plane Tree, and shares its characteristic plated, pale bard, peeling off in multi-colored sections, resembling a puzzle or topographical map.

  1. RoundHeaded BushcloverLespedeza capitata Round-Headed Bushclover

During the summer, this native legume is working hard, fixing soil nitrogen, and feeding solitary bees. In the winter the soft, fuzzy seed heads sway in the wind, on top-heavy stems like something out of a Dr. Seuss book, flinging their seeds one by one. If nothing else, they will make your winter garden a more bizzare and amusing place

  1. Staghorn SumacRhus typhina – Staghorn Sumac

Sumacs need space to realize their true potential. Their widely spreading and colonizing habit make appear architecturally designed, especially in winter when the branches are bare. Sumac berries are a staple mid-winter food for many large birds and small mammals.

6.  Red CedarJuniperus virginiana – Red Cedar

This slender evergreen tree will take some of the harshest upland growing conditions. Red Cedar tolerates drying winter winds, and summer drought. In early winter, its berries are a favorite of Cedar Waxwings, and other songbirds. Planting in staggered rows can provide an ideal wind-break and snow-fence.

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Solidago ridelliiGreen roofs have become increasingly popular in cities. They provide a wide range of benefits such as reducing cooling costs, providing storm water management and being beautiful. One of the most desirable benefits of green roofs is their ability to providing natural habitat for local wildlife and pollinators. Green roofs provide sanctuaries for birds and insects in traditionally hostile urban environments and birds have even been recorded to use green roofs as nesting sites.

However, the most common plant used on green roofs are sedums. Sedums are non-native, succulent plants. They are used because they are low-lying, drought resistant and can be grown in mats which make greening a roof less heavy or time intensive to install. While Sedums do provide some benefits of reducing energy use and helping to manage storm water, they do very little in terms of sustainability and providing viable habitat for wildlife.  As an article in Scientific American put it, “A roof planted with sedum […] is no greener, from the standpoint of sustainability, than is ordinary tar or asphalt.”[1]

The low lying, tightly bunched nature of sedums does not provide the habitat the birds require. Wild flowers and grasses are more suited to the needs of nesting birds. Additionally, native plants provide food for the birds in the form of seeds and the insects that the plants attract. Sedums do not. Instead, the non-native plants tend to attract non-native insect species. The Green Roof Innovation Testing Laboratory at the University of Toronto found that Sedum green roofs were attracting non-native bee species, and while native bee species did use the sedums, they were more likely to be pollinating native plant species.

Brown Eyed SusanNative plants have the advantage that they have co-evolved with the local species. Many native pollinators feed exclusively on particular plants, meaning Sedums can never replace the role of the native plant. Local plant species are finely tuned to provide the habitat and food that the wildlife needs, and to support the populations throughout the season. Wildflowers bloom at different points throughout the season, so that there is a continuous food supply. Flowers in spring and summer attract insects which baby birds need, and then in fall plants produce berries and seeds that sustain the bird populations throughout the winter.

Native plants are the right fit for green roofs as these species are ideally suited to the local environment. Find nurseries that have sourced seeds from your seed zone, and you’ll know that the plants will survive whatever weather is thrown at them. Additionally, the variety in shapes, sizes and colours of native species can keep things interesting by creating a dazzling display that changes throughout the season. Many native prairie grasses and wildflowers do well in the heat and the sun that green roofs are exposed to. Additionally, there are many species whose roots systems do well in 4 to 6 inches of soil, lending them well to the shallow growing conditions of green roofs.

Fragaria virginiana (1)Check out the city of Toronto’s Guidelines for Biodiverse Green Roofs[2] for some plant suggestions. One great species the report suggests is Wild Strawberry (Fragaria virginiana). This plant requires only 4 inches of soil, is low growing, produces fruit to feed birds and has beautiful dense foliage that turns red in fall.

In 4 to 6 inches of soil, many different grasses and meadow flowers can establish themselves. Plant a mix of species to increase the diversity, which in turn will provide more services for wildlife. Take a look at our seed mixes for inspiration on plants that do well together. Our Shallow Groundcover mix is ideally suited for green roofs, because their root systems do well in shallow soil. It includes plants such as Slender Wheat Grass (Elymus trachycaulus), Brown Eyed Susan (Rudbeckia hirta), Evening Primrose (Oenothera biennis), and Dwarf Blazing Star (Liatris cylindracea).

If you’re considering a green roof, talk to your designer about using native plants!



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Photo Credit: Arnold Aroboretum

The Kentucky Coffee Tree (Gymnocladus dioicus) is produced by St. Williams Nursery and Ecology Centre and grown in a variety of formats and sizes.  This unique deciduous tree is currently on the province of Ontario’s Species at Risk List as “Threatened” as of 2008 when the Endangered Species Act took effect.

The Kentucky Coffee tree grows 15-25 metres high and produces leaves as big as 60×90 centimetres, which are considered the largest leaves produced by any Canadian tree.  The fruit produced comes in a bean-like pod and contains four to seven seeds that remain on the tree throughout the winter.

The two main threats to the Kentucky Coffee tree are lack of suitable habitat and poor seed production.  In the latter, Male and Female flowers are produced on separate trees and unless these trees are growing in proximity of each other the trees will not produce seeds.

Interesting Facts:

  • Part of Gymnocladus dioica means “naked branch”, this is because the tree spends up to nine months of the year without any leaves.
  • Kentucky Coffee tree seeds are toxic to mammals. However, elephants are known to devour similar seed pods, and because of this it has been hypothesized that the Mastodons that once roamed the earth may have consumed these pods.

St. Williams Nursery and Ecology Centre has Kentucky Coffee (Gymnocladus dioica) available in the following formats at a variety of heights:

  • 1 year plug liner
  • Bareroot Field Transplants Liners
  • Potted Stock

For more information click here

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SWNaEC-logo-v2As we head into 2017 I am proud of all that we have accomplished at St. Williams Nursery and Ecology Centre over the past six years.  We have achieved much in pursuit of our mission to help preserve and restore Ontario’s natural biodiversity.  We have brought together some of the leading conservation scientists in the province and have successfully transformed a conventional forestry seedling nursery into one of the largest conservation nurseries in North America for our cause.  At St. Williams Nursery and Ecology Centre, we now produce millions of  wild-type source identified native plants (trees, shrubs, and forbs – grasses, sedges,  wildflowers, ferns and aquatic plants) and thousands of kilograms of native seed mixes that are the foundation for ecological restoration and biodiversity conservation projects.  Our native plants and seed have been planted throughout the province on our own ecological restoration projects such as the Highway 407East Habitat Compensation Project as well as by many conservation partners including Conservation Authorities, urban foresters, ecologists, government agencies, park managers, highway managers, school groups, NGOs and private citizens.

The conservation of native biodiversity remains a serious environmental challenge, and one that is complicated by global warming.  The landscape and horticultural industry as a whole in North America does not have a good track record when it comes to conserving native biodiversity.  Historically, the nursery industry has too often promoted exotic species over natives, and unwittingly has introduced many harmful exotic diseases (e.g., Dutch Elms Disease, Chestnut Blight) and invasive species (e.g., European Buckthorn, Phragmites) that have significantly impacted our native species and natural ecosystems.  An important aspect of biodiversity conservation now is to preserve local genemonarchtic biodiversity of native plants by collecting seed from wild populations and propagating new plants for restoration, landscaping and gardening.  It is essential that we restore and maintain healthy native plant communities in our landscapes in order to preserve the natural biodiversity of our province and country.  St Williams Nursery and Ecology Centre will continue to do our part as a leading biodiversity conservation organization in Ontario, tracking and monitoring native plant populations, and growing source-identified seed and plants for conservation.  I am excited to announce our new initiative to develop a Native Species Conservation Network seed database for Ontario in 2017 which will allow us to better work with more conservation partners to achieve our biodiversity conservation goals.  Biodiversity conservation is a big undertaking and we will require many partners  to work with us to plant source-identified wild type native plants in their landscapes, workplaces, parks and gardens…let’s bring nature home.

Yours in conservation,

Allan Arthur, M.Sc.
President, Sr Ecologist
St Williams Nursery and Ecology Centre

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Panicled Aster (Symphiotrichum lanceolatum) in the understory; Burlington

Restoration biologists aim to return ecological function to degraded landscapes, by using plants to recreate healthy ecosystems. Landscapes that have been actively disturbed are restored by planting trees, meadows, wetlands and gardens. There is increasing interest to reshape the spaces we have disturbed into healthy and productive ecosystems, with a focus on the use of regionally appropriate native species.

Though we have gone to great lengths to shape the land, plants are the original ecosystem engineers.

Swamp Milkweed (Asclepias incarnata); Tobermory

Swamp Milkweed (Asclepias
incarnata); Tobermory

Plants are the foundation of every terrestrial ecosystem on earth. Their primary function is to provide animals with food, and materials to make shelter, but they also clean the air, and provide us all with oxygen. Plants also cool us with shade, and buffer us from floods.

Similarly, native plants are the foundation of regional ecosystems they are native to. Though often overlooked as the green backdrop upon which life’s drama unfolds, the specific identity of the plant communities that surround us is important.

Natives are species which occur in a region naturally. They have evolved over generations to exploit resources and cope with challenges found within their home region. Because they have evolved in the same ecosystem, native animals often prefer and sometimes depend exclusively on native plants.

Restoring native plants is a critical first step for conserving ecosystems. Avoiding the use of nonnative plants, especially well documented invasives, in our landscapes will also help to prevent further ecological damage.

The greatest threat to native plant diversity is loss of habitat from development, and the associated spread of exotic plants species. Some of the most invasive plant species in Ontario were introduced with the best of intentions to provide forage for our domestic animals, and to make our neighborhoods more beautiful. The cost of these invasions is more than space; we are paying for these mistakes with the loss of distinct and diverse communities of native plants and their associated fauna. Restoring native species to our landscapes increases the quality of forage and habitat for wildlife, but it also helps us plan for and mitigate the effects of climate change.

blue flower

Virginia Bluebells (Mertensia virginica); Oakville

Since native plants are adapted to the local environment, they can tolerate regional variations in moisture and temperature better than many traditional, introduced, cultivars. While also being more attractive and rewarding to insects, native wildflowers, for example, are more drought tolerant and cold hardy than their cultivar counterparts, or non-native analogues.

We can use this to our advantage, and plan landscapes of native plants that require fewer inputs, and in the end lower costs to create and manage. There are even native plants adapted to harsh environments that mirror our disturbed urban and suburban environments, such as roadsides and other infrastructure corridors, rooftops, construction footprints, and old fields — native plants that thrive on river bluffs, alvars, sand dunes and fire-prone prairies.

Though they are hardy, wild populations of native plants are increasingly fragmented by development. This makes migration extremely difficult for many plant species in Ontario. Without the ability to migrate, these plants may not be able to cope with a changing climate, and without reconnecting populations through assisted migration, they may fail to adapt to the change. Land stewards who are interested in restoring native plant ecosystems can help by enhancing native plant population sizes and creating gene flow between populations by establishing new patches.

Whether you appreciate nature in the water, casting off the side of your canoe, or you appreciate it in the air, through the lens of your binoculars, conservation begins in the ground with the seeds and roots of native plants.

Article courtesy Stefan Weber, Ecologist – St. Williams Nursery & Ecology Centre

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Latornell-Logo-Refresh-20th-outlined-tree-transparentIn mid-November staff from St. Williams Nursery and Ecology Centre attended the annual Latornell Conservation Symposium. Latornell is the preeminent conservation conference, bringing together government ministries, conservation authorities, policy makers, nongovernmental organizations, academics and businesses to discuss the challenges and future of conversation. The conference provides a great opportunity to share ideas and learn what others have been doing to help protect Ontario’s environment.

This year’s theme focused on green infrastructure and how it is an important part of tackling a host of issues such as climate change, biodiversity loss, water management, public health and fostering sustainable communities. Green infrastructure includes living systems such as natural areas, forests, parks, streams and riparian zones, wetlands and agricultural lands, as well as engineered facilities such as green roofs, rain gardens and stormwater ponds.  It can be implemented at multiple scales including regional networks of open spaces, agricultural lands, natural areas, and through site-specific practices.

Latornell_2016_Green_Infrastructure_Logo_v2-171x300Keynote speakers Dr. Faisal Moola and Dr. Dianne Saxe kicked off the conference. Dr. Faisal works with the David Susuki Foundation and has spent years working to protect wild areas such as the Great Bear Rainforest, and working with communities to establish local natural areas, such as the Homegrown National Park in Toronto. In his talk, Dr. Faisal reminded us that natural spaces have amazing beneficial impacts on the health of the communities who enjoy them. Next time you’re feeling stressed, go for a walk out in nature and reap the benefits!

Dr. Dianne Saxe is the Environmental Commissioner of Ontario. Previous to taking on this arms-length, government watch-dog role, Dr. Dianne was a highly respected environmental lawyer. In her current position she works hard to keep the public informed and the government in check, working to protect the environment and prepare for the future. Dr. Dianne talked about the Environmental Bill of Rights, which gives Ontarians the right to know about — and have a say in — government decisions that affect the environment. If you want to know more about an issue or a specific project, have a say in what the government is doing, or voice a concern, you’ll find the resources you need on the website of the Environmental Commissioner of Ontario.

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Allan Arthur M. Sc., President, St. Williams Nursery & Ecology Centre.

On Tuesday, November 29, 2016, St. Williams Nursery and Ecology Centre President, Allan Arthur presented and participated in a panel discussion at the Landscape Ontario (LO) Growers Dinner.  Specifically, Allan spoke about the philosophy and history of seed zones and why St. Williams Nursery and Ecology Centre believes in the value of using seed zone sourced plants.  He also provided comments about the future and impact of seed zones to the nursery industry.


St. Williams Nursery & Ecology Centre President, Allan Arthur M. Sc., with Landscape Ontario Executive Director, Tony DiGiovanni.

The Landscape Ontario Growers’ Dinner was a great opportunity to engage with other LO members to better understand the important role of source-identified wild-type native plants for biodiversity conservation in Ontario.   “We were very pleased to be able to share our St Williams Nursery and Ecology Centre  vision and to discuss the opportunities as well as challenges that we face in the production and marketing of native plants in Ontario.   It is clear that there is strong and increasing market demand for source-identified Ontario native plants,” said Allan Arthur.  “We hope that LO and the Ontario industry as a whole embrace the opportunity to become leaders in helping to sustain Ontario’s natural biodiversity through the acceptance and promotion of source-identified native plants.”


Panel discussion (from Left to Right): Melissa Spearing, Barb MacDonald, Allan Arthur.

In addition to Allan’s presentation, there were excellent presentations by Barb MacDonald (on the MTO experience with native species on the Herb Gray Parkway) and Melissa Spearing  (on seed zone science, policies and the implications of climate change).  All three served to give members a good perspective of the issues as the industry evolves.


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This Month’s Ask An Expert Question Is: What are Seed Zones and why are they important?

Seed Zone 1Seed Zones are biogeographic regions, created to help track and promote the use of locally-sourced tree seed for reforestation. Not to be confused with ‘Plant Hardiness Zones’, a ‘Seed Zone’ tells you the region where the seeds that’s your native plants were grown from was collected.   Our system of Seed Zones, created by the Ministry of Natural Resources and Forestry, group together watersheds with similar climates, based on the Ontario Climate Model (OMNRF, 1997).

Seed Zones are important for tracking where seed comes from and also for deciding where the best locations to plant them are. Some species can be locally adapted, meaning they tend to perform best in the environmental conditions of their parents. In the absence of additional, species specific data, the general recommendation then is that you should plant trees derived from as close to your seed zone as possible, because they will be adapted to local conditions and perform better than an individual of the same species grow from seed far from your home Seed Zone.

Some populations may be locally adapted, some may not be. Though they may seem like hard-and-fast rules, Seed Zones were not created to restrict the movement of seed, only to have a unified tracking system, to better inform our decisions. In fact, there may be microclimates beyond an individual’s Seed Zone or adjacent zone that provides the optimal growing conditions. This is because local adaptation is not as generalizable as geographic climate data, and because each species will be locally adapted to different conditions, and to different degrees.

Seed Zone 2There are no strict rules on Seed Zones in Ontario, they are offered simply as a guiding principle. Allowing seed and plants to be transferred between zones actually encourages gene-flow which promotes adaptation to future environmental changes. It may also be practical in order to make up for stock limitations within a given zone.

It’s also important to note that Seed Zones were created for trees, and extended later to grasses, shrubs, and wildflowers. We can expect that trees can adapt to long-term climate patterns, whereas shorter-lived herbaceous species—grasses and wildflowers—are less likely to be adapted to long-term climate patterns, and mores so to small-scale environmental differences like soil type, or moisture level, disturbance regime, or community of competitors. There have been numerous studies on the assisted migration of native trees in Ontario, however, very few studies have been conducted on the level and scale of local adaptation in native herbaceous species, and best practices for their assisted migration and restoration in the face of climate change.

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comboBlooming later and longer than most native asters in southern Ontario, the Sky-Blue Aster (also known as Azure Aster) is one of the most attractive as well. Its pale lavender-blue flowers form low frothy mounds that attract late season pollinators (Sept-Oct) like monarch butterflies, complimenting the colour of fall leaves in the landscape.

Sky-Blue Aster prefers full fun and well drained soils. It typically grows 1/2m tall and equally wide. It is drought tolerant and requires little care in a garden setting. For best results in the garden, prune back nearly to the ground every spring. Leave the spent flowers in the fall, the developing fluffy seed heads will provide food to songbirds.

 smooth aster heart leavedSt. Williams Nursery & Ecology Centre also grows two similar though distinct species: Smooth Aster (S.leave), and Heart Leaved Aster (S. cordifolium). All three have pale indigo coloured flower heads and the same general low, bushy shape. Smooth Aster, which has more rubbery leaves, can tolerate a wider range of soils, though their flowers are often slightly more purple. On the other hand, heart Leaved Aster is found more in understory, or forest-edge habitats, and tends to bloom a bit later, with pale, almost white flowers.

Sky Blue Aster Fast Facts


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