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Constructed Wetlands

This third phase of the garden is in strong contrast to the first two. Spread over 15 acres, and encompassing a series of 19 ponds, the scale is dramatic. If you walk the entire pathway system you will have covered 1.3 kilometres. Planted with hundreds of trees and shrubs, native plants, perennials and wetland plants, the site is truly impressive.

The south end of the site near the Heritage Barn and main entrance is the most formal, moving towards the north end, the feel becomes much more informal and natural. The Gazebo on the top of Celebration Hill provides the best vantage point to see the garden in it's entirety. What is not obvious to the eye is the function of the ponds - treating and polishing run-off water from the campus, and providing incredible research opportunities in the area of waste-water treatment.

Heritage Barn and Entrance

The main entrance to the East portion of the gardens is at the south end, next to the red barn - a heritage feature on campus which honours our agricultural past. This will be the future home of our interpretive centre. The formal entrance way leads through an impressive set of gates, flanked by large containers, planted to add emphasis and seasonal interest. Walking through to the Four Season Commons, you'll see different types of paving stones, set in different patterns - one in the entrance way, another across the Commons, and a third as you head up to Celebration Hill. Our intent is to showcase some of the variety of materials available, and the ways in which they can be used.


Four Season Commons

This area stretches east to west near the formal entrance to the gardens. At one end is a grass tent area, framed by ash trees (Fraxinus spp.) – a perfect setting for any event. Moving west, in the center of the plaza are four raised beds. Each is home to mixed plantings of shrubs, perennials and bulbs chosen to showcase plants that meet their peak season of interest in each of our four seasons. The Spring bed has early-blooming micro-bulbs and double-flowering plum (Prunus triloba ‘Multiplex’) as well as spring perennials such as cushion spurge (Euphorbia epithymoides). In the Summer bed you’ll find purple coneflower (Echinacea purpurea ‘Magnus’, weigela (Weigela florida ‘Bramwell’), and alliums (Allium holandicum ‘Purple Sensation’).

The Fall bed relies on late blooming perennials such as sneezeweed (Helenium ‘Mardi Gras’) and asters (Symphytrichum novae-angliae ‘Purple Dome’) as well as ornamental grasses that put on their best show at this time of year. Many shrubs change colour in fall, offering a hit of orange or red and we’ve chosen to include Prairie Fire dogwood (Cornus sericea spp. sericea ‘Prairie Fire’). Winter interest in the final bed will be created with bark colour from the dogwood (Cornus sericea ‘Isantii’), and evergreen shrubs such as Blue Star juniper (Juniperus squamata ‘Blue Star’). Many perennials stand up well over the winter – you’ll see a repetition of the ornamental grasses, purple coneflower, and alpine seaholly (Eryngium alpinum ‘Blue Star’). Flanking the Commons are statuesque elm trees (Ulmus americana ‘Brandon’). Frequently used as street plantings, these high-headed trees will grow over time to arch over the Commons, framing and shading this formal area.

At the far west end of the Commons are two large open turf areas. Perfect for picnics and for children to play, future plans involve a large ornamental reflecting pond and a conservatory.


Our botanic gardens are an ideal outdoor setting for social and cultural events.This 100-seat amphitheatre is set into sloping formal lawns overlooking the final pond of the wetland series. It offers a unique function space that is available to host weddings, arts performances, lectures and interpretive talks, all made more memorable because of the spectacular outdoor environment.

Crabapple Allée

Crabapples are frequently found in prairie gardens. Close relatives to apple trees (they are members of the same Malus genus), the edible fruit they bear are smaller, two inches in diamater or less. Considered tart, they can be used for jams and jellies. Crabapple trees are very hardy, quite drought tolerant and boast wonderful spring blooms. Flowers can be single, semi-double or double, lasting as long as two weeks. Bloom times vary depending on the type of tree and the weather conditions that year, but typically will start in late April into May. As the pathway leads from the Four Seasons Common, the trees on the lower half below the Amphitheatre are those varieties with white flowers (including ‘Dolgo’ and ‘Rosthern’ ), while the upper half leading to the Gazebo are pink (including ‘Hopa’, and ‘Big River’). This use of matching rows of trees flanking a pathway is an example of an ancient landscape feature called an allee, designed to draw the garden visitor towards a landscape feature, in this case the Gazebo at the top of Celebration Hill.

When moving along this pathway, take a moment to read the engraved bricks on the edges. They have been purchased by families, friends, individuals and organizations to pay tribute to past and present members of the campus community. These are part of our Set in Stone program. The funds generated go towards ongoing care of the site.

Celebration Hill

The best vantage point in the garden is from the Gazebo on the top of Celebration Hill where you will be treated to a view of the entire Botanic Gardens and Constructed Wetlands. Surrounding the Gazebo are over 1200 perennials representing more than 30 varieties of prairie-hardy selections. Designed to be viewed from all vantage points, we’ve used plants ranging in size, texture and bloom times. Large groups have been used, in some cases up to 20 plants in each, aiming for the impact dictated by a garden of this size. Emphasis is placed on plants that provide winter interest and food for local bird species. Ornamental grasses add texture and movement throughout the year. These plants were propagated from seed or grown from plugs in the College greenhouses. 

Highlights of the selections include four cultivars of feather reed grass (Calamagrostis actutiflora ‘Karl Foerster‘, ‘Avalanche’, ‘Overdam’ and ‘Eldorado’) allowing a comparison between the taller, non-variegated ‘Karl Foerster’ and the smaller cultivars with varying stripes in the foliage of silver and cream. Also included is Joe Pye weed (Eutrochium purpureum 'Maculatum'), elephant ears (Bergenia crassifolia 'Bressingham Ruby and 'Erioca'), sneezeweed (Helenium 'Mardi Gras') and daylilies (Hemerocallis 'Stella d'Oro' and 'Little Grapette'). For a backbone we’ve used shrubs such as mugo pine (Pinus mugo) and cultivars of dogwood (Cornus spp.). These will not only add a feeling of permanence to the planting, but will provide winter interest through evergreen needles and coloured bark. Dressing up the Gazebo are long low planters planted with a variety of succulent plants – a good choice for a warm, sunny, and potentially windy site, as they thrive in dry conditions, requiring less water than many other plants.

Fescue Meadow

This north-facing slope extending down from Celebration Hill has been seeded with a fescue mix and is maintained in such a way as to create a lawn, much like you might find in a residential yard.

Research Ponds

These ponds do not have plant material permanently installed, instead they have floating booms of plants chosen based on the needs of the specific research project. Although all the ponds in the Constructed Wetlands are used for research purposes, there is a series of four that have been ear-marked for specific research projects. These four ponds (Ponds 1, 7, 11 and 16 on the map) are managed by the Olds College Centre for Innovation. In collaboration with industry partners, opportunities are available to investigate cold-climate wetland functioning in the treatment of wastewater from a variety of sources. These ponds differ from many of the other ponds in the system. They have been constructed using a triple-lined system that guarantees that no water introduced to these ponds will escape.

Land & Environment Research

Polishing Ponds

Each pond was planted with 750 plugs of aquatic plants, one species in each pond. Plants were chosen for their hardiness (all are Alberta native species), ability to adapt to fluctuating water levels, and ease of propagation among other factors. Natural wetlands play an important role in the environment by improving the quality of the water that moves through them. As water makes it way downstream through the series of ponds that make up the constructed wetlands, the quality of the water is changing, and in order to measure this change, sensors have been installed in each pond. They measure parameters such as pH, temperature, dissolved oxygen, turbidity, levels of nitrogen and other nutrients and much more. This information is remotely transmitted and over time will be made available to researchers and to the public.

Aquatic plants play a role in the treatment process. They slow the flow of water allowing sediment to settle to the bottom and keeping the water clear. As they use nutrients in the water to grow they reduce their concentration to acceptable levels. Plants found in wetlands may even remove contaminants such as metals from the water.

In our constructed wetland, different planting approaches have been used. The first two ponds (2 and 3) and the last pond (17) before the Natural Pond have been planted using a mix of native and ornamental plants with an emphasis on displaying the diversity found in aquatic species – different foliage sizes and shapes, attractive blooms, and examples of the different growth habits found. A second planting approach has been used in a set of nine ponds - three series of ponds with three ponds in each. Each pond has been planted with a single species, chosen for their ability to remove materials from the run-off water that flows through them. One series has three carex species (Carex aquatilis, C. lacustris, C. utriculata). The second has three species of bulrush (Scirpus acutus, S. microcarpus, S. validus). The last series has three different genera – horsetail (Equisetum fluviatile), rush (Juncus arcticus) and cattail (Typha latifolia). Each species will be monitored for their performance in the wetland and our challenge will be to keep each pond as a monoculture, avoiding movement of plants between the ponds.

Natural Pond

Natural wetlands are disappearing at an alarming rate, causing concern at the loss of the role they play in creating essential habitat, improving water quality, providing human recreation activities and reducing the incidence of flooding, drought and erosion. The Constructed Wetlands project was driven by a need to respond to the Alberta Government’s “Water for Life” strategy which raises the awareness of this ongoing loss. While the majority of this constructed wetland is focused on the treatment of wastewater and the associated research activities, the Natural Pond has been designed to mimic naturally occurring wetland ponds in its structure and appearance. A mix of native willows such as sandbar willow (Salix interior) and Bebb’s willow (S. bebbiana) inhabit the upper slopes, enjoying the moisture available to them, and helping to protect the soil from erosion. Keep your eyes out for local wildlife species such as muskrat, birds, and insects such as dragon flies as this pond starts to attract local wildlife. To learn more about the value of wetlands see the Ducks Unlimited website.

Woodland Walk

Shade is a valuable commodity on the prairies offering protection from the heat of the sun and shelter from the wind. The Woodland Walk on the west side of the garden supplements an existing row of native white spruce (Picea glauca) which formed a shelterbelt for the site before the garden was installed. The path meanders from the west entrance down towards the Four Season Commons creating a peaceful and tranquil experience. The trees used are a mix of deciduous and coniferous species, providing contrasting shapes and forms through all four seasons. Paper birch (Betula papyrifera), white and blue spruce (Picea glauca, P. pungens) and ponderosa pines (Pinus ponderosa) predominate. They are offset by understory plantings of shade-tolerant shrubs including hydrandeas (Hydrangea spp.), false spirea (Sorbaria sorbifolia ‘Sem’) and pink-fruited snowberries (Symphoricarpos x doorenbosii 'Kordes'). Soon we’ll be adding perennials and groundcovers to complete the layering associated with woodland ecosystems. 

The carpet of wood chips on these and other beds in the gardens helps to retain moisture in the soil and prevent the growth of weeds. Mulch mimics the effects of leaf litter and is considered an essential part of any sustainable garden.


The term ‘arboretum’ comes from the latin word ‘arbor’ for tree. It is used to describe a collection of trees that are cultivated for scientific, educational and ornamental purposes.  Our Arboretum is focused in the area across from the main south entrance, but extends into the rest of the gardens – in between the ponds, through the Woodland Walk, and up to the north end of the garden.

The collection includes many familiar species, but where possible we have chosen less familiar cultivars. For example, Ivory Silk Japanese tree lilac (Syringa reticulata ‘Ivory Silk’) is found in many Alberta gardens and several have been planted near the corner of the red barn. We’ve also chosen to try a cultivar newer to the market – ‘Golden Eclipse’, which displays golden yellow and green variegated leaves. Several poplar species and cultivars can be found including browntwig poplar (Populus tristis), northwest poplar (P. x jackmanii ‘Northwest’) and Assiniboine poplar (P. x ‘Assiniboine'), but be cautious, these trees are fast growers, and can grow to become be very large specimens. This illustrates one of the values of an arboretum – a chance to see trees in a garden setting before you choose one for your own yard or landscape. Other notable trees include amur cherry (Prunus maackii) and the unusual amur maackia (Maackia amurensis). This tree's olive-green bark, pea-shaped flowers and compound leaves indicate its membership in the Fabaceae family, but it's single-stem form and architectural branching habit create a very different look from the familiar caragana (Caragana spp.).

Pheasants Forever Central Parkland

This north-west corner of the site has a variety of microclimates and soil conditions, and care was taken to make close observation, matching the plants to the specific growing conditions. A substantial swale was constructed to direct run-off water from the campus into the treatment wetlands, and the plantings along this swale include tree and shrub forms of birch (Betula spp.), white spruce (Picea glauca), wild roses, (Rosa spp.), gooseberries (Ribes oxycanthoides) and strawberries (Fragaria virginiana). Higher areas are home to plants such as trembling aspen (Populus tremuloides), Paskapoo poplars (Populus balsamifera ‘Paskapoo’), limber and lodgepole pines (Pinus flexilis, P. contorta var. latifolia), saskatoons (Amelanchier alnifolia), wolfwillow (Elaeagnus commutata), junipers (Juniperus spp.) and bearberry (Artctostaphylos uva-ursi). A backbone of containerized trembling aspen anchor the north end, interplanted with mostly bare-root stock provided by local growers. One particularly low spot has been populated with cattails (Typha latifolia) and wetland grasses. A native grass mix covers the open areas and will be left virtually untouched with the exception of occasional mowing.

Many of these plants are suitable for the home garden, being hardy and well adapted to our climate, as well as great habitat for local wildlife. Look out for additions of native forbs to be added in the coming seasons.

North Pond Area

A mix of willows illustrates the diversity found in this genus showcasing the variety of heights and forms, foliage shapes and colours, catkins and bark. Specimens found in this area include sandbar willow (Salix interior), diamond willow (S. eriocephala) and meadow willow (S. petiolaris). Intermingled are plants associated with the Boreal ecoregion including balsam fir (Abies balsamea) and alders (Alnus spp.). Herbert birch (Betula papyrifera 'Herbert') originated from a seed source, selected by Bow Point Nursery, east of Olds above the Red Deer River which is south of the paper birch’s normal range. The name was chosen in honour of the late Dave Herbert who was known for his excellent plantsmanship. He was also an influential and popular instructor at Olds College, and was instrumental in the development of the Olds College Botanic Gardens and Constructed Wetlands.

Across the pond Siberian larch (Larix sibirica) create a stunning back drop – look for their needles to change colour and then drop as winter approaches. It is an example of a deciduous conifer – a needle-bearing tree that is not an evergreen, but sheds its needles each winter. Siberian larch is a close relative of the native tamarack (L. laricina) but typically it is what is seen more frequently in urban landscapes. Along the pathway are found ornamental trees such as elms (Ulmus americana), mountain ash (Sorbus aucuparia), ponderosa pine (Pinus ponderosa), Schubert chokecherry (Prunus virginiana ‘Schubert’) and ash (Fraxinus spp.) The grass found in this area is a mix of fescue (Festuca spp.). Fescue mixes are becoming more popular in landscape situations as they are very hardy, slow growing, with low water and fertility needs. This leads to a turf that only needs mowing every few weeks and requires no additional water after they have become established.