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Compound
leaves, predominately yellow autumn leaf colour, attractive finely
furrowed bark, and the ability to thrive on most sites on the prairies
make ash the most popular prairie tree. Green ash may have been
overplanted on the prairies because of its adaptability to the basic
soils, dry conditions and cold climate. Since ash is so popular,
urban planners should be aware that there is a wide selection of green
ash cultivars along with other ash species and hybrids to choose.
Where ash borer and seed gall mite are a factor, ash cultivars with
resistance to those insect problems should be selected.
To
optimize the best prairie adaptation, all of the ash cultivars listed
below are budded (grafted) onto green ash roots. Black ash (Fraxinus
nigra) is the only one listed that is growing on its own
roots. All the green ash and white ash cultivars are male
therefore they do not produce any seed. When planting green or
black ash seedlings, there is usually a 50% chance that the tree will be
female and therefore will produce seed. The Northern Treasure
cultivar has a few female flowers and produces a few seed. However, the
amount of seed produced is limited and the percentage of viable seed is
very low. Planting a variety of ash cultivars and species in the
urban environment will help in successful urban forest management.
| Cultivar Name |
Mature Height
|
Mature Width
|
Foliage
|
Fall Colour
|
Shape,
Features, Resistance and Hardiness
|
| Northern Blaze® Fraxinus americana
'Jefnor'
|
45-50'
(14-15m)
|
30-35'
(9-10m)
|
Large, glossy, med. green |
Yellow, mid fall
|
Upright in juvenile stage and broadens
with age, hardiest White Ash, male and Zone 3. |
| Mancana Fraxinus mandshurica
'Mancana'
|
35-40'
(10-12m)
|
30'
(9m)
|
Feather like foliage |
Yellow, early fall
|
Dense compact canopy and oval form.
Golden twigs, seed gall mite, resistance, male
and Zone 3. |
| Black Fraxinus nigra
|
40-50'
(12-15m)
|
25-30'
(7.5-9m)
|
Coarse compound leaves |
Yellow early fall
|
Coarse branching, open canopy, tawny coloured branches,
dark buds, Zone 2. |
| Fallgold Fraxinus nigra
'Fallgold'
|
40-50'
(12-15m)
|
20-25'
(6-7.5m)
|
Coarse, compound leaves |
Yellow, early-mid fall
|
Coarse branching, narrower crown, drops
leaves later, very susceptible to seed gall mite
male, Zone 2. |
| Northern Gem Fraxinus nigra x mandshurica
|
35-40'
(10-12m)
|
30-35'
(9-10m)
|
Large, narrow, waxy and |
Yellow, Early fall
|
Round to broad oval form, seed gall
resistance, Zone 3. |
| Northern Treasure Fraxinus nigra x mandshurica
'Northern
Treasure'
|
40-45'
(12-15m)
|
30-35'
(9-10m)
|
Large, narrow, waxy |
Yellow. early fall
|
Upright and vigorous growth, hardier
than Northern Gem, limited seed, seed gall
resistance, Zone 3. |
| Foothills Fraxinus pennsylvanica
'Heuver'
|
40-45'
(12-15m)
|
35-40'
(10-12m)
|
Wide, medium sized |
Yellow, mid fall |
Compact branching, upright, oval crown
and said to be Chinook hardy, seedless, Zone 2. |
| Green Fraxinus pennsylvanica
|
50-60'
(15-18m)
|
40-45'
(12-15m)
|
Narrow, small to medium |
Yellow Early-mid fall
|
Grows on a wide range of sites, variety
of crown shapes, female or male trees, Zone 2. |
| Patmore Fraxinus pennsylvanica 'Patmore'
|
50-60'
(15-18m)
|
35'
(14-15m)
|
Glossy, dark green, narrow |
Yellow, mid fall
|
Upright branching with a oval crown,
very attractive foliage, seedless Zone 3. |
| Prairie Spire® Fraxinus pennsylvanica
'Rugby'
|
50-60'
(15-18m)
|
25-30'
(7.5-9m)
|
Glossy, wide, deep green |
Yellow, mid fall
|
Narrower form than species, orange tinge
on juvenile bark, very hardy, seedless, Zone 2. |
| Summit Fraxinus pennsylvanica 'Summit'
|
50-60'
(15-18m)
|
25-30'
(7.5-9m)
|
Glossy, med. green, very narrow |
Yellow, mid fall
|
Upright branching and oval shape crown,
with attractive foliage, Zone 3. |
Written by Rick Durand - research and development program at Jeffries
Nurseries
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