Fraxinus- Ash Flashcards
Fraxinus
Ash
Faxinus pennsylvanica var. subinteggerima
green ash
Fraxinus nigra
Black ash
Fraxinus mandshurica
Manchurian Ash
Fraxinus americana
White ash
Green ash characteristics
conical-upright oval grown
open (not dense)
single trunked
medium to high headed (good street tree)
mature- more cylindrical
Green Ash Buds
opposite buds
terminal buds (yellow) are scaly, dark rusty brown*
Sparsely pubescent (hairy)
terminal buds often flattened and much larger than axillary buds (red) which tend to be rounded
very little space between terminal bud and axillary buds
Green Ash- leaves
(good identifier)
Compound leaf- odd pinnate, 5-7 leaflets*
end leaflet (yellow) largest in size
serrate margins
petiolule leaflet attachment
Petiole
is the stalk that holds the leaves/leaflets
Petiolule (if present)
is the stalk that holds the leaflets (only on compound leaves)
Rachis
the continuation of the petiole inside a compound leaf
Sessile
means no petiolule- leaflet attached directly to petiole
Green Ash Flower
dioecious; male flowers and female flowers on different trees
female flowers: more green, rugged and thick, can be prolific seed producers
flowers commonly appear before leaves
Green ash fruit
Samara
wings are long, straight sided and thin; like a canoe paddle*
Benefits of Dioecious trees in landscaping
Gravitate towards the males so there is less seeds dropping
Green Ash- autumn colouration
golden-yellow
usually the last to get leaves in spring and the first to drop leaves in autumn (negative feature)
Green Ash Bark
ashy, textured
non-descript
Green ash cultivars
mostly tall, more narrow upright trees
Foothills Green Ash (male,seedless)
Patmore Green Ash
Prairie Spire Green Ash
Bergeson Green Ash
Green Ash Pest
Most common: Ash flower gall mite (only affects male trees), ash plant bug, ash cone roller
Emerald ash borer (not yet in SK)
Ash flower gall mite
mostly/only on male trees
mite attacks male flowers, causing them to form into a gall; retained for years
not overly harmful; cosmetic problem
“Tree broccoli” hang on for a long time
Ash plant bug
nymphs live on underside of leaf
piercing action causes speckled look
behaves like an aphid
Ash cone roller
rolls leaf
makes cocoons
not likely to kill tree
strange expression on tree; cosmetic
Fraxinus nigra
black ash
Black ash characteristics
Leaves look a little droopy, because of the length of the compound leaf
more columnar shape
prefer wetter sites
yellow/golden fall colour
Black ash- cultivar/hybrid
cultivar most common ‘Fall Gold’
hybrids are more commonly planted- ‘Northern Treasure Ash’ (male), ‘Northern Gem’ (male)
Black Ash- bud
axillary buds round
dark brown to black
often a small space between terminal bud and axillary buds
Black Ash- Leaf
Rounded to broadly acute at base
tapered from well above the middle to a slender tip
7-11 leaflets (most commonly 9)
leaflets sessile
brown hairs at base of leaflet
Fraxinus mandshurica
manchurian ash
Manchurian ash- characteristics
ornamental
leaves longer than other ash; leaves droop more than black ash
Manchurian Ash- leaf
largest number of leaflets (9-13) hence why they droop
leaflets sub-sessile (very short petiolule)
rusty hairs at base of leaflets
serrate leaf margins
rusty brown hairs along veins and at axils
rachis and petiole can be slightly winged (cannot roll between fingers)
Manchurian ash- bud
axillary buds rounded dark brown to black
very little space between terminal bud and axillary buds
stems often two sided rather than rounded
Manchurian Ash-bark
bark is golden colour
Manchurian Ash- cultivar
Faxinus mandshurica “Mancana”: fairly common front yard tree
medium sized tree- showy
nice round shape
Manchurian Ash- pest
cottony ash psyllid, “jumping tree lice”, not on green ash
Cotton Ash psyllid
black and manchurian ash and hybrids are particularly affected.
devastating for trees
nymphs enter leaves like a leaf miner-difficult to spray or control
death of trees is very common
