Evaluating Woody Plants for Hardiness and Landscape Quality in Alberta

Since 1983 the Regional Woody Plant Test Project (RWPTP) has been evaluating new woody plant species and cultivars in Alberta. It is a cooperative trial between Alberta Agriculture and Food Crop Diversification Centre South (CDCS), the Landscape Alberta Nursery Trades Association Growers Group and Research Committee and five current and four past nursery cooperators. The nursery cooperators donate the space and maintain the plant material on their site.

In the RWPTP, plants are monitored for landscape quality and hardiness for six years. At the end of the evaluation period, recommendations are made about the suitability for growing in the following regions which represent much of the climatic diversity of Alberta: Fairview, Edmonton, Red Deer, Calgary, Brooks and Lethbridge areas. Plant material for the trial has generally been chosen from North American nurseries with a few selections from around the world.

The RWPTP was terminated in 2009, with the last data being collected in the fall of 2009.

Cultivar Evaluations

Definitions of Categories in Report

Recommendations
H -- Highly recommended
R -- Recommended
S -- Recommended, but needs extra care
N -- Not recommended
F -- Failed because of unfavourable soil conditions, weed competition, mechanical or animal damage.

Recommendations in lower case letters are based on less than the six growing seasons of observations or plants require extra maintenance.

Trial average
The average height of the plants after six growing seasons, unless noted. This is not necessarily the mature size of the plant.

Rating
A numerical index based on the scores recorded each year at evaluation, winter injury and landscape quality characteristics are the main criteria for rating the plants.

Annual scoring
0 -- dead
1 -- poor, low sprouts
2 -- major dieback
3 -- fair, injury to branches
4 -- good, some tip kill
5 -- excellent, no injury

Terms used in plant descriptions
Alkaline conditions: high pH and/or saline soil conditions.
Urban conditions: includes air pollution such as car exhaust, salt spray, excessive heat, poor soil, wind tunnel effect.
Roadside conditions: includes salt spray, pollution, poor soil.
Bleeding: sap movement in the spring which results in weeping or 'bleeding' from any pruning cuts; thus, these species must be pruned after leafing out. Species affected - maple (Acer), birch (Betula), walnut (Juglans).
Juniper blight: tips of affected branches first turn brown, followed by progressive dieback until entire branches are dead.
PP (followed by a 4 digit number) -- a patented plant.
PPAF -- a cultivar for which a plant patent has been applied for.
TM -- a trademark is declared and has been filed for registration.
COPF -- a cultivar propagated under agreement with the Canadian Ornamental Plant Foundation.
® -- indicates a registered trademark

Additional notes
Deer are a problem in most sites. High pH and alkaline soil conditions contributed to lower scores at Coaldale, and to a lesser extent at Calgary. Some plants have not been reported. Lonicera x korolkowii 'Zabelli' had a major black aphid infestations on all sites. Other plants were obviously misnamed or mixed up.

Botanical plant names are based on the sources: Manual of Woody Landscape Plants, M.A. Dirr 1990 and Hortus Third, 1976.


Acknowledgments

Many thanks to all of the people who have directed, cooperated, or contributed to this project since its inception in 1983.

Brendan Casement	Retired leader Agro Foresty Program, CDC North, Edmonton		Han Kuperus	Coaldale Nurseries, Coaldale
George Granger	Retired leader Agro Foresty Program, CDC North, Edmonton		Lemoine Maryniak	CDC North, Edmonton
Karen Barby	Green Haven Garden Centre, Lethbridge		Bev Minsky	City of Edmonton, Old Man Creek Nursery
Dwayne Beck	Parkland Nurseries, Red Deer		Dr. Christine Murray	CDC South, Brooks
Doug and Chris Berggren	Alberta Nurseries and Seeds, Bowden		Herman Oosterhuis	CDC North, Edmonton
Tom Bidart	Fairview College, Fairview		Thean Pheh	CDC North, Edmonton
Simon Bos	Simon Bos Nurseries, Coaldale		Bev Rogerson	Willow Valley Nursery, Grande Prairie
Don Hay	Lacombe Nurseries, Lacombe		Cathy Safronovich	CDC South, Brooks
John Helder	City of Edmonton, Old Man Creek Nursery		Nigel Seymour	CDC South, Brooks
Henry Heuver	Foothills Nurseries, Calgary		Angela Spencer	CDC South, Brooks

Trial Location	Cooperators		Trial Locations	Cooperators
Bowden	Alberta Nurseries and Seeds		Edmonton	Crop Diversification Centre North
Brooks	Crop Diversification Centre South		Fairview	Fairview College (beginning 1994)
Calgary	Foothills Nursery		Grande Prairie	Willow Valley Nursery (terminated 1992)
Coaldale 1*	Coaldale Nurseries (terminated 1992, collected final data 1994)		Lacombe	Lacombe Nurseries (terminated 1991)
Coaldale 2*	Simon Bos Nurseries (beginning 1994)		Lethbridge	Green Haven Garden Centre (beginning 2004)
Edmonton 2	Old Man Creek Nurseries (beginning 2003)		Red Deer	Parkland Nurseries (beginning 1991)

*An empty box under a site indicates the plant was not tested at that location. In Coaldale the RWPTP has been located at two different sites: 1 (83 - 94) and 2 (94 - present). In some cases the same selection was planted at both locations, differences in the recommendations are a result of differences in soil and water conditions.