Exploring Explorer roses

By Bob Osborne, Corn Hill Nursery, Petitcodiac, NB

The last two decades have been a tremendously exciting time for the northern rose grower. In the past, cold country gardeners have looked at pictures of English cottage gardens with their doorways draped in riotous climbing roses with a mixture of envy and repressed anger. We no longer need to be envious or angry for we now have at our disposal a veritable cornucopia of roses that are hardy, easy to grow, beautifully formed and disease resistant to boot. These roses have come out of breeding programs in Europe, the United States (U.S.) and Scandinavia, but the most important of all have been developed in our own backyard.

Since the turn of the century, both amateur and professional rose breeders have been pushing the limits of roses further north. Some of the most important of these pioneers were people like Frank Skinner from Manitoba, Percy Wright from Saskatchewan, Georges Bugnet, Robert Simonet and John Wallace from Alberta, and doctors Isabella Preston, Henry Marshall and William Saunders from the Department of Agriculture. Using hardy rose species crossed with the best garden roses, they created varieties that were much hardier than any that had been produced previously. Many of these had good form and bloomed far longer than earlier hardy roses.

In this tradition, Agriculture Canada began a rose breeding program in the 1960s under the direction of breeder Felicitas Svejda. Her objective was to use roses from these earlier efforts and cross them with newly developed roses from Europe to create a series of roses that would be hardy, disease resistant, repeat blooming and easy to propagate from cuttings. A key component in this program was a new hybrid, Rosa kordessii, developed by the firm of Kordes in Germany. This rose was a relatively hardy pillar rose with long, vigorous shoots and exceedingly healthy foliage. Dr. Svejda also used several repeat blooming and compact Rosa rugosa varieties such as ‘Fru Dagmar Hastrup’ and ‘Schneezwerg’. The results of this ambitious program have forever changed northern rose gardens. In order of their release, here is a quick look at the roses that have come to be known as the Explorers.

Martin Frobisher (1968)
Jens Munk (1974)
John Cabot (1978)
David Thompson (1979)
John Franklin (1980)
Charles Albanel (1982)
Louis Jolliet (1990)
Simon Fraser (1992)
Frotenac (1992)
George Vancouver (1994)
Lambert Closse (1995)
Royal Edward (1996)
Nicholas (1997)
Quadra (1997)
Marie Victorin (1998)
William Booth (1998)
De Montarville (1998)
Martin Frobisher (1968)
This is a soft, semi-double and fragrant rose that grows on a vigorous, upright bush. It repeats well and is well formed. Its main drawback is a tendency for sections of the bush to die out.

Jens Munk (1974)
This fragrant Rosa rugosa hybrid is a medium pink semi-double. The bush is an arching upright grower with healthy foliage. It makes a superb hedge plant. Perhaps its best feature is its fall bloom, which nearly equals the spring bloom.

Henry Hudson (1976)
This seedling of Rosa rugosa ‘Schneezwerg’ is very floriferous and blooms until frost. The buds are tinted pink but open pure white with snowy yellow stamens. It is quite fragrant. The foliage is very healthy and the bush remains compact, rarely growing more than 1 m in height. It is hardy in Zone 3 and probably protected sites in Zone 2.

John Cabot (1978)
This long-shooted pillar rose owes its habit and glossy foliage to the Rosa kordessii. It can be used as a climber and will reach 3 m in a good site. It will tolerate temperatures of -35°C without winterkill. The double blooms are soft red in bud, opening to deepest orchid pink. It has a second flush of flowers in late summer. Lightly fragrant.

David Thompson (1979)
This is a compact bush growing to 2 m with soft mauve-red blooms that have a few white streaks in the centre. Its best attribute is its long blooming season. The flowers are fragrant and the foliage is very healthy. It is also a good candidate for hedging.

John Franklin (1980)
A very floriferous, clear red semi-double rose with fringed petals, John Franklin is not quite as hardy as many Explorers, experiencing winterkill at approximately -25°C, and is unfortunately more susceptible to blackspot than any of the other Explorers. It has no fragrance.

Champlain (1982)
This semi-double, deep red rose is one of the best-known Explorers because it is continuously blooming. The small bush has very disease-resistant foliage. It is not quite as hardy as most explorers, experiencing winter damage at temperatures below -25°C, however the base and roots of the plant usually survive well and will rebound in the spring. It has a very light, spicy fragrance.

Charles Albanel (1982)
A low-spreading Rosa rugosa hybrid, it is ideal for covering banks or for use along roadsides or in parks. Its flowers are deepest pink, fragrant and recur throughout the season. The foliage is deep green and healthy.

William Baffin (1983)
Perhaps the most propagated of all the Explorers because of its tremendous vigour and long season of bloom, this upright grower will reach heights of 3 m or more. Its bright pink, semi-double flowers are very showy and its foliage is resistant to blackspot and mildew, although it is somewhat susceptible to leafspot. It is among the hardiest of all cultivated roses, easily surviving -40°C. It has little fragrance.

Henry Kelsey (1984)
This was the first hardy climber that was a true red. The semi-double blooms open to reveal bright yellow stamens. Its rambler-like habit makes it suitable for tying to fences or upright on a trellis. Its leaves are glossy green and only occasionally touched by blackspot. They are lightly fragrant and the wood can take temperatures of -32°C without winterkill.

Alexander MacKenzie (1985)
The flowers of this vase-shaped plant are very well formed, reflecting on one of its parents, the popular grandiflora ‘Queen Elizabeth’. The foliage on this plant is deepest shiny green, with a red tint to the newest leaves. It will suffer some winter damage at temperates of -30°C, but the bush will survive up to -38°C or so. Most people find its raspberry fragrance delightful although interestingly, some people can not smell any of its fragrance.

John Davis (1986)
This Rosa kordessii hybrid was a breakthrough in flower form, closely resembling the popular ‘Bonica’, but much hardier, surviving temperatures of -40°C with little damage. The blooms are medium pink and shapely, with a light fragrance. The bush has deep red new stems and arches outward, eventually growing to 2 m, making it suitable as a low climber.

J.P. Connell (1987)
Strictly speaking, this is not a true Explorer because its parentage is not related to the others. However, because it was released by the research station that created many of the Explorers, it is now associated with them. It has very shapely cream yellow blossoms that fade to ivory white. It repeats later in the season, a trait that gets better as the bush ages. The fragrance is delightful. The bush stays in bounds, rather suckering and grows nearly vertical. It will suffer winterkill around -32°C, but will survive much lower temperatures.

Louis Jolliet (1990)
A rose whose greatest attribute is its abundant bloom, Louis Jolliet is a vigorously growing, generally upright bush, making it suitable as a low climber. The blooms are a deep pink colour with a somewhat muddled double form. It is lightly fragrant and hardy to nearly -40°C.

Captain Samuel Holland (1990)
The blooms of this upright pillar rose resemble tiny hybrid teas and come in large clusters throughout the season. The medium-green foliage is very healthy and the bush is hardy to -35°C without damage. This plant makes a good climber. It is not particularly fragrant.

Simon Fraser (1992)
An interesting rose whose first blooms are usually single, Simon Fraser’s later blooms are somewhat more than single. They are an attractive salmon pink and occur in profusion throughout the season. The bush is small and compact with very healthy foliage. It will experience winterkill at temperatures below -32°C but survives temperatures well below that.

Frontenac (1992)
This small bush blossoms nearly continuously with semi-double, medium pink flowers. The form is somewhat loose and blowsy. It has little fragrance. The foliage is very healthy. It is difficult to get enough wood for propagation.

George Vancouver (1994)
A wonderful addition to the Explorer series, George Vancouver is easily winter hardy to -35°C and will survive much lower temperatures. The bush is relatively low and somewhat spreading with exceedingly healthy foliage. The flowers come in clusters, and are semi-double with a soft red colour that fades to deepest pink. It is a very good late season bloomer.

Lambert Closse (1995)
This small bush produces silvery pink, star-like blooms that resemble the hybrid teas. It has good fragrance and good repeat blooms. The foliage is very glossy, however some blackspot will appear on the lower leaves in some years. Lambert Closse is hardy to -32°C.

Royal Edward (1996)
This plant is a cross with a miniature rose (Rosa polyantha) and its tiny leaves and low spreading habit bear this out. Its diminutive stature makes this a useful rose for the edging of beds or for spots where a larger rose would be out of place. The semi-double pink blooms are small but shapely and appear in profusion throughout the season. They have little fragrance. The bush appears fully hardy to -30°C or perhaps much lower.

Nicholas (1997)
A wonderful small plant that produces small clusters of semi-double, scarlet-red blossoms, Nicholas has proven to be quite hardy, surviving open ground conditions and temperatures of -35°C with virtually no winterkill. It is a promising and very floriferous long-season bloomer. The bush has shown no blackspot or mildew. The flowers have little fragrance.

Quadra (1997)
If the author had to forecast the future, he would probably choose this Explorer as having the brightest future. The deep velvet red flowers of ‘Quadra’ are very double, symmetrically formed somewhat like the old Rosa gallicas. They occur throughout the season on a very healthy, moderately vigorous and upright bush. The foliage is deep green and infused with red, particularly near the growing tips. It has a very light fragrance. The bush is fully hardy to -35°C.

Marie Victorin (1998)
Marie Victorin is a stunning rose whose shapely buds are pink with orange-yellow highlights. Its blooms open to create a double blossom with silvery peach-pink petals and yellow reverse. The fragrance is exquisite. The bush is moderately vigorous with medium green foliage that is generally healthy, although some blackspot may appear on older leaves in later summer. Hardy to -35°C.

William Booth (1998)
This member of the Explorer series is a Rosa kordessii hybrid with tremendous vigour. William Booth’s deep red stamens grow outward at a 45 degree angle but can be tied upright to form a climber that, in time, will probably reach 4 m. Clusters of red buds open to reveal single blossoms of soft red with a white eye. It somewhat resembles the once popular rambler ‘American Pillar’ but blooms until frost and is hardy to -40°C, without winterkill.

De Montarville (1998)
This new, semi-double rose is deep rose red in bud and fades to medium pink when open. It is shapely and flowers throughout the season. The bush is smallish, eventually reaching 1 m in height and width. It has shown winter injury in open conditions when temperatures drop below -30°C.

Recently, the federal government, in its infinite but perhaps shortsighted wisdom, has decided to terminate the Explorer breeding program. It is unfortunate because the new generations of seedlings promised exciting breakthroughs in colour, form, hardiness and health. Equally unfortunate is the fact that this program has given and would have continued to give Canadian rose growers and exceptional opportunity to capture an important share of the exploding world market for shrub roses.

In reaction to the unexpected uproar over this decision, a new scaled down version of the program was initiated in partnership with a group of participating nurseries from across Canada. This program hopes to release three or four varieties in the upcoming years that will be named after Canadian artists. Thankfully, we can still look forward to more exciting hardy roses in the future, roses that will grace the walls and beds of our homes in ways we would have thought impossible only a few short years ago.

Bob Osborne is owner of Corn Hill Nursery near Petitcodiac, NB. He is author of Roses for Canadian Gardens and Hardy Trees and Shrubs, published by Key Porter Books. He has also published numerous articles on horticultural subjects in Canadian Gardening, Fine Gardening and Chatelaine. The CBC gardener for CBC Radio in Moncton, NB, Mr. Osborne has also contributed to the gardening series at the Brooklyn Botanical Gardens and published numerous articles in the Journal of the International Plant Propagators Society (IPPS).

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