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Fraxinus nigra - Black Ash |
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Bud break - ash flowers in early may.
Dark colored, bluish to black, felt-like buds and sessile leaflets
Pistillate flowers, Early May
7-13 sessile leaflets on the compound leaf, Scaly, flaky, corky bark.
Young, 'Fallgold' black ash displaying fall color
5/15/2004 - Cottony ash psyllid symptoms on newly emerging leaves of black ash.
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All Images By: Dave Hanson |
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- Characteristics
- Disease Management
- Links
This Minnesota native and its cultivars are becoming more popular. It is proving to be a good street tree that tolerates urban conditions and soils.
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| Medium tree height: |
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30-50' |
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| Canopy spreads: |
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20-35', Often a narrow, rounded crown. |
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| Drought Tolerance: |
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Intermediate |
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| Shade Tolerance: |
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Intolerant |
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| Soil pH Tolerance: |
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Intolerant to high pH |
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| Poor Soil Drainage: |
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Tolerant to flooding |
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Salt Tolerance:
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Tolerant to salt spray and Intermediate to soil salts. |
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In Minnesota this species is found growing in bottomlands and on the edges of northern coniferous swamps and bogs. There are a few varieties available in the nurseries: Fallgold, Northern Gem, and Northern Treasure are the most popular. All of these are adaptable to urban conditions and are developing a good record as street trees. Fallgold is listed as seedless, while the others are listed as limited seeders.
Did you know
According to "Minnesota Trees" by David Rathke, this tree was often referred to as "hoop ash". When pounded the wood separates at the growth rings into flat strips that historically was used in basket weaving, for mats and in fish traps. |
| DISEASE |
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SYMPTOMS |
MANAGEMENT |
| Anthracnose,
Apiognomonia errabunda |
Fungi
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Initially,
tiny purple/brown spots on young leaves.
Spots enlarge, coalesce and form brown
blotches. Leaf distortion common. Young
shoots may be killed back. Defoliation
may be severe. |
Remove
fallen leaves and dead twigs and branches,
especially on young trees.
CHEMICAL: Chlorothalonil, mancozeb,
thiophanate-methyl or zyban beginning
at budbreak. |
| Ash
yellows, caused by a phytoplasma (mycoplasma-like
organism) |
Phytoplasma
(MLOs)
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Severe
reduction in growth, chlorotic leaves
in tufts at end of branches along with
dieback. Witchesâ brooms may form on
the trunk. |
Maintain
tree vigor to prolong life. Remove
as they become hazard trees.
CHEMICAL: None.
REFERENCE: Ash Yellows in Minnesota,
MI-5898-C. |
| Heart
rot, Perennoporia fraxinophila |
Fungi
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Crumbly,
soft decay in trunks and larger limbs.
Groups of bract-shaped, grayish-white
perennial conks appear along the infected
branches and trunk. |
Remove
dead and dying branches. Avoid mechanical
injury.
CHEMICAL: None. |
| Sulfur
shelf heart rot, Laetiporus sulfureus |
Fungi
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Brown
cubical rot of roots, butt and trunk
with sunken elongate cankers on the
surface. Bright yellow to orange, fleshy
fungal reproductive structures appear
in summer and fall. |
Proper
pruning: avoid mechanical injury.
CHEMICAL: None. |
| Verticillium
wilt, Verticillium dahliae |
Fungi
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Acute
or chronic symptoms may appear anytime
during the growing season. Chronic:
small, chlorotic leaves, leaf scorch,
slow growth, abnormally heavy seed
crop, shoot dieback. Acute: leaf curling
or scorching, abnormal red or yellow
color, partial defoliation, wilting,
and branch dieback, plant death. Symptoms
often on only one part of the tree
or shrub. |
This
wilt is soilborne; replace with resistant
tree species. Keep infected trees well
watered and fertilize with a fertilizer
high in potassium. Remove dead branches.
CHEMICAL : None. REFERENCE: Verticillium
Wilt of Trees and Shrubs AG-FO-1164 |
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