Arboretum

RBG’s Arboretum is more like an English landscape park than a garden. As its name implies, this is the place where you can see a wide variety of trees and other woody plants up close. It is especially beautiful in spring and fall. Two Arboretum landmarks are Rasberry House, named for the family that operated a market garden and dairy farm on this site for nearly 100 years, and its adjacent silo. The handsome old house, which sits up on the hill to the north, now serves as headquarters for the Bruce Trail Association. The Arboretum is large, and with exception of the lilac walk and the shrub collection areas, has few formal paths. It is also a great place for watching and experiencing other animal plant interactions.

Click on the map above to learn more about each area.

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Katie Osborne Lilac Collection (Lilac Dell)

Peak interest: May and early June

The Lilac Dell exhibits over 600 species and cultivars of common lilacs. French hybrids form the basis of the collection, but also displayed are Preston hybrids (originated in Canada by Isabella Preston), early-bloomers such as hyacinth lilacs and a selection of species found in the wild. An introductory Lilac Walk at the entrance to the Lilac Dell is organized in a series of exhibits that interpret the desirable breeding characteristics of lilacs, and major developments in the history of lilac breeding. On more challenging terrain, The Katie Osborne Lilac Collection in the Lilac Dell is one of the most diverse and one of the definitive collections to demonstrate the range of the genus Syringa. A popular seasonal attraction, it provides visitors with weeks of delightful springtime colour and fragrance. Visit during the Lilac Festival (late May) and enjoy special tours and demonstrations.

The family of Hamilton lilac enthusiast Katie Osborne originally developed the Lilac Dell through a generous memorial donation. RBG is proud to be the home of the International Registration Authority for new lilac cultivars.

Magnolia Collection

Peak interest: April and May

Magnolias are among the most primitive of flowering plants, with fossil remains dating from over 100 million years ago. Relatively unchanged since then, they are found in the wild in tropical and temperate Asia and America. The collection, located in two separate locations in the Arboretum, displays a selection of magnolias that are hardy in our area. The collection also exhibits Ontario's native magnolia, the cucumber-tree (Magnolia acuminata), an endangered species found wild in only a few locations in the Carolinian Zone. The western section of the collection was originally developed as a memorial to local architect Lester Husband, while the eastern section, near the Synoptic Shrub Collection, commemorates past Gardens’ staff member R. A. Sims.

Ontario Native Trees & Shrubs

Peak interest: all year RBG lies near the northern limits of the Carolinian Life Zone (Deciduous Forest Region), Canada's most threatened habitat. Hickory, sassafras and walnut give our forests a distinctly southern flavour. Along with these southern trees you'll find maple, beech and hemlock—species characteristic of the more northerly Great Lakes-St. Lawrence Forest Region.

Cross the barrier from our cultivated arboretum and enter our natural lands where you will find scores of tree species native to Ontario. Many have grown here naturally, while others have been planted.

This collection was established in 1972 through the generosity of the late W.A.T. Gilmour, Hamilton businessman and naturalist.

Hedge Demonstration

Peak interest: all year

Prior to pressure treated fences, hedges were commonly used as living barriers and as green walls attracting insects, birds and other animals. Traditional hedges are often labour intensive plantings, requiring regular use of gas-powered equipment to maintain their shape. Some of these traditional species are showcased in this collection but you will also find some lower maintenance, slow growing alternatives, including white pine (Pinus strobus). The demonstration also showcases species not commonly seen as hedges, such as lilac (Syringa) and hornbeam (Carpinus).

Dogwood (Cornus) and Redbud (Cercis) Collection

Peak interest: May

RBG’s woodlands are home to some species more commonly found in the southern United States. For example, south of the lilac dell the collection of dogwoods (mostly Cornus florida and its cultivars) and redbuds (Cercis canadensis) at the edge of this woodland provide a springtime show of mauve-pink and white blossoms. A member of the Pea Family, redbud reaches the natural limits of its range near Lake Erie, though it can be planted further north. Interestingly, Cornus are commonly used as shrubs in the landscape but can reach 5m tall in their natural habitat.

The Maze

Peak interest: all year

Mazes have been a source of frustration and delight for at least 4,000 years. All around the world, various cultures have used them for defense, ritual, amusement and as traditional garden elements.

Almost 300 white cedars (Thuja occidentalis) have been used in our maze. Twenty white cedar cultivars make up a design of four concentric circles, allowing you to contrast their colour and texture.

The maze was developed with the financial assistance of the Hamilton Spectator.

Synoptic Shrubs

Peak interest: all year

The Synoptic Shrub Collection presents a living encyclopedia of shrubs that can be grown in our area. Like a dictionary, it is organized alphabetically, by genus, from A to Z. It includes species as well as cultivated plants commonly available in the horticultural trade as well as unusual shrubs that are harder to find and have been sourced form other botanical gardens through plant exchanges. Currently undergoing rejuvenation, visitors will be able to see how a collection of mature shrubs can be revitalized.

Weeping Trees

Peak interest: all year

With property sizes shrinking in recent years, weeping trees have increased in popularity. While some stay small, others can grow into giant trees. Many of the cultivars we display originally came from selected upright parent trees with an abnormal growth form. Others are grafts, where a low-spreading plant has been elevated to tree status, by joining it to the trunk of an upright form of the same species. The visitor will be able to get a glimpse into the future and see what their newly planted tree will become.

The Pinetum

Peak interest: all year

Also called evergreens, needle-leaved trees or softwoods, conifers are trees whose seeds are open to the air, most often in cones. Most keep their leaves for at least two years, and all have soft resinous wood.

Ontario's tree emblem reflects the major role that some members of this group of plants have had on our history—the British Navy's demand for white pine (Pinus strobus) shaped the early settlement of our province. Along with pines, the Pinetum explores the diversity of conifer genera around the world.

Crabapples

Peak interest: May (flowers) and fall (fruit)

Our display highlights the range of form and colour in the Malus genus. Crabapples are a common small tree used in residential landscapes. Over the years RBG has grown and evaluated many of the hundreds of cultivars bred from the two-dozen or so wild species found in North America, Europe and Asia.

Avenues of Trees

Peak interest: all year

Radiating from the central parking circle, avenues of trees showcase many tree species grown in open, sunny spaces, allowing them to show off their natural forms. Each avenue illustrates a unique form, including large boulevard trees, conical-shaped trees, globe-shaped trees, medium-size oval-headed trees, fastigiate (upright) trees and small-size flowering trees. Many of the avenues end in a circle of trees of one species or cultivar. By far the most spectacular is the tulip tree (Liriodendron tulipifera) circle near the Synoptic Shrub Collection.

Beech (Fagus) Collection

Peak interest: all year

Beech trees are treasured for their stately appearance, smooth grey bark, glossy leaves, slow growth and enormous size. This collection features both the European beech (Fagus sylvatica) and its cultivars, and the American beech (Fagus grandifolia). Included are cultivars that have columnar or weeping forms, or various leaf colours including green, yellow, purple and pink. Individual trees have been planted with enough space to allow them to exhibit their natural form at maturity.

Flowering Cherry Collection

Peak Interest: April/May

At RBG, our flowering cherries are part of our early spring celebrations. Globally, flowering cherry trees have a long history especially in Japan where the cherry blossoms are celebrated each year. Every year flowering times are recorded and noted and this has occurred for around the past 1300 years. RBG also annually records the flowering times of its cherries as part of a biological science known as phenology which is an important tool in helping to track climate change. In 2010, we added 34 trees to this collection donated to RBG as part of the Sakura Project. These trees are planted at both the Arboretum and Rock Garden sites and are a must see in early spring.