Ash Tree Identification

A d o p t e d A u g u s t 2 0 0 7 U n i v e r s i t y o f M i n n e s o t a E x t e n s i o n

Emerald

Ash Borer

Ash sp ecies attack ed b y em erald ash b orer inclu de g reen

(Fraxinus pennsylvanica), w hite (F. americana), b lack

(F. nigra), and b lu e (F. quadrangulata), as w ell as horticu l-

tu ral cu ltiv ars of these sp ecies. G reen and w hite ash are

the m ost com m only fou nd ash sp ecies in the M idw est

w ith b lu e ash b eing rare.

W hile other w oody p lants, su ch as m ou ntainash and

p rick ly ash, hav e “ ash” in their nam e, they are not tru e

ash, or Fraxinus sp ecies. O nly tru e ash are su scep tib le to

attack b y em erald ash b orer.

To properly identify ash trees, use the following criteria:

MICHIGAN STATEU N I V E R S I T Y

EX TENSIO N

B ranch and B ud A rrangem ent

B ranches and b u ds are directly across

from each other and not stag g ered. W hen

look ing for op p osite b ranching in trees,

p lease consider that b u ds or lim b s m ay

die; hence not ev ery sing le b ranch w ill

hav e an op p osite m ate.

L eav es

L eav es are com p ou nd and com p osed of

5 -1 1 leaflets. L eaflet m arg ins m ay b e

sm ooth or toothed. The only other op p o-

sitely b ranched tree w ith com p ou nd leav es

is b ox elder (A cer negundo ), w hich alm ost

alw ay s has three to fiv e leaflets. W hite ash

(on left) and g reen ash (on rig ht)

B ark

O n m atu re trees (left), the b ark is tig ht

w ith a distinct p attern of diam ond-shap ed

ridg es. O n y ou ng trees (rig ht), b ark is

relativ ely sm ooth.

Identify ing ash trees b y their b ark is difficu lt. U se this in

com b ination w ith other indicators.

S eeds

W hen p resent on trees, seeds are

dry , oar-shap ed sam aras. They

u su ally occu r in clu sters and

ty p ically hang on the tree u ntil

late fall, early w inter.

Diane B ro w n-R ytlew sk i

*P aul W ray, Io w a S tate U niversity

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B lack A sh W hite A sh

Tree S pecies R esem b ling A sh

A s h Tr e e I d e n t i f i c a t i o n

M S U is an affirm ativ e-action, eq u al-op p ortu nity institu tion. M ichig an S tate U niv ersity E x tension p rog ram s and m aterials are op en to all w ithou t reg ard to race, color,national orig in, g ender, relig ion, ag e, disab ility , p olitical b eliefs, sex u al orientation, m arital statu s, or fam ily statu s. • Issu ed in fu rtherance of E x tension w ork in ag ricu l-tu re and hom e econom ics, acts of M ay 8 and J u ne 3 0 , 1 9 1 4 , in coop eration w ith the U .S . D ep artm ent of Ag ricu ltu re. Thom as C . C oon, E x tension director, M ichig anS tate U niv ersity , E . L ansing , M I 4 8 8 2 4 . • This inform ation is for edu cational p u rp oses only . R eferences to com m ercial p rodu cts or trade nam es do not im p ly endorse-m ent b y M S U E x tension or b ias ag ainst those not m entioned. This b u lletin b ecom es p u b lic p rop erty u p on p u b lication and m ay b e p rinted v erb atim w ith credit toM S U . R ep rinting cannot b e u sed to endorse or adv ertise a com m ercial p rodu ct or com p any . R ep - 3 :0 7 - 1 0 M - K M F/L B

MICHIGAN STATEU N I V E R S I T Y

EX TENSIO N

B ox elder (A cer negundo )

E x hib its op p osite b ranching and com p ou nd leav es.

H ow ev er, has 3 to 5 leaflets (instead of 5 to 1 1 ) and the

sam aras are alw ay s in p airs instead of sing le lik e the ash.

B lack W alnut (J uglans nigra)

L eav es are com p ou nd w ith 9 to 1 5

leaflets, b u t the p lant has an alternate

b ranching hab it. F ru it is a larg e dark

b row n nu t inside a g reen hu sk .

E lm (U lmus species)

B ranching is alternate and the leav es are sim p le w ith an

u neq u al leaf b ase.

S hagb ark H ick ory (C arya o vata)

L eav es are com p ou nd w ith 5 to 7 leaflets, b u t the p lant

has an alternate b ranching hab it. F ru it are hard-shelled

nu ts in a g reen hu sk .

Au thors: K im b erly R eb ek and M ary W ilson

E uropean M ountainash (S o rb us aucuparia)

L eav es are com p ou nd w ith alternate (stag g ered) b ranch-

ing . Tree b ears clu sters of cream y w hite flow ers in M ay .

F ru its are fleshy , red-orang e b erries.

Diane B ro w n-R ytlew sk i *B o ris H raso vec, U niversity o f Z agreb

*P aul W ray, Io w a S tate U niversity *P aul W ray, Io w a S tate U niversity *P aul W ray, Io w a S tate U niversity *P aul W ray, Io w a S tate U niversity

*P aul W ray, Io w a S tate U niversity *B ill C o o k , M ich igan S tate U niversity

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