Photo by Melody

PlantFiles: Hoptree, Stinking Ash, Wafer Ash
Ptelea trifoliata

Family: Rutaceae (roo-TAY-see-ee) (Info)
Genus: Ptelea (TEL-ee-uh) (Info)
Species: trifoliata (try-foh-lee-AY-tuh) (Info)

5 vendors have this plant for sale.

16 members have or want this plant for trade.


15-20 ft. (4.7-6 m)

12-15 ft. (3.6-4.7 m)

USDA Zone 5a: to -28.8 C (-20 F)
USDA Zone 5b: to -26.1 C (-15 F)
USDA Zone 6a: to -23.3 C (-10 F)
USDA Zone 6b: to -20.5 C (-5 F)
USDA Zone 7a: to -17.7 C (0 F)
USDA Zone 7b: to -14.9 C (5 F)
USDA Zone 8a: to -12.2 C (10 F)
USDA Zone 8b: to -9.4 C (15 F)
USDA Zone 9a: to -6.6 C (20 F)
USDA Zone 9b: to -3.8 C (25 F)

Sun Exposure:
Light Shade


Bloom Color:
Pale Green

Bloom Time:
Mid Summer


Other details:
Average Water Needs; Water regularly; do not overwater

Soil pH requirements:
5.1 to 5.5 (strongly acidic)
5.6 to 6.0 (acidic)
6.1 to 6.5 (mildly acidic)
6.6 to 7.5 (neutral)
7.6 to 7.8 (mildly alkaline)

Patent Information:

Propagation Methods:
From softwood cuttings
From semi-hardwood cuttings
From seed; direct sow outdoors in fall

Seed Collecting:
Allow pods to dry on plant; break open to collect seeds

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There are a total of 20 photos.
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7 positives
4 neutrals
No negatives

Gardeners' Notes:

Positive flowergirl70 On Nov 11, 2014, flowergirl70 from Stayner, ON (Zone 5b) wrote:

A great little tree. Dark glossy green leaves, turning a med. yellow in fall, rather late, after most others. White fragrant flowers with rounded wafer like seeds afterwards. Bark is a reddish brown, also attractive.
Grows in my Zone 5a garden in Ontario, Canada, in full sun. No self seeding issues yet. And no butterflies yet.

Positive Rickwebb On Aug 23, 2014, Rickwebb from Downingtown, PA wrote:

This is not a shrub-tree that is one of the flashy plants for the ornamental garden. This species goes well with the newer thinking from the American Native Plant Movement that one should plant for the sake of good ecology, being a food source for beneficial wildlife as birds and insects, and naturalizing, not just for ornament and decoration. It is an interesting plant, and one person in these files uses it to attract a butterfly species, which is very good. I used to have a photo of a wild specimen in northern Illinois that I found in the wild, but lost it long ago. It is not a common plant in most of its native range from TX to west NY and from central FL to central MI and also some of the Southwest.

Neutral coriaceous On Mar 3, 2014, coriaceous from ROSLINDALE, MA wrote:

This performs in full sun and also in heavy shade. Native here and normally grows as a woodland understory tree, usually multitrunked.

In British gardening books this is often praised as one of the best of fragrant plants. The flower fragrance is strong enough to perfume the air, but I find it unpleasantly heavy. I find the green flowers are ornamentally insignificant.

This self-sows here to the point of weediness.

Dirr gives hardiness to Z3.

Neutral gtbabic On Jul 7, 2013, gtbabic from The Villages, FL wrote:

In central FL, zone 9B, this might be a bit too far south for Hoptree (at least, the one I have). It was growing well through spring, then when real constant heat hit in July, it started to fade with wilted leaves. Now in mid-July it appears to be on its last legs with about half the leaves gone and the rest wilted. It is in full sun, perhaps if it was in part-shade the story would be different.

Positive Cuppagio On Jul 29, 2011, Cuppagio from Erie, PA wrote:

Live in Northern Pennsylvania. This plant grows natively along the shores of Lake Erie. It will tolerate sun or shade and clay soil. We planted it to attract our summer butterflies like the Giant Swallowtail. Yes, Lake Erie has them, they fly up from south of here in the river valleys and then evidently because of the Rue family plants like Prickly Ash and Wafer Ash (Hoptree) they will breed and host here.

We put two of these shrubs/trees in our yards and one at a local school. From a distance they have a wonderful aroma when in bloom (here in Erie, June). The early leaves when crushed smell lemony. Later foliage has an unpleasant smell when crushed.

And finally, we now have Giant Swallowtails visiting our yard. Getting pictures of them is difficult as they are more wary than our other types of swallowtails.

Positive xtrucker On Jun 30, 2011, xtrucker from Wellfleet, MA wrote:

We planted this little stick about 10 years ago and it is now a tree about 15 ft tall and 20 ft wide. It flowers every year but we have never seen the seed wafers. We wonder if it needs another Hoptree? It is beautiful in our zone 6 -7 but we have rough winters and it did loose some of it's limbs last year. We love it.

Positive LindaTX8 On Oct 5, 2008, LindaTX8 from NE Medina Co., TX (Zone 8a) wrote:

Hop Tree is a great small understory tree or a shrub that flowers with clusters of small greenish-white slightly fragrant flowers in spring and then makes the wafer-like seeds. It's a host plant for the caterpillars of the Giant Swallowtail and the Two-tailed Tiger Swallowtail, both large, beautiful butterflies. I wish I had lots of these little trees!

Positive rosemarysims On Apr 28, 2006, rosemarysims from Mermentau, LA (Zone 8b) wrote:

I was surprised to see the comments of the scent of this tree. The reason I first noticed it was that in full bloom, the flowers cast their citrusy scent into the air. It drew me all the way across a large garden! It was like being in a orange grove at bloom time.

As for the scent of the foliage, I too find it to be mildly unpleasant, but the scent only manifests itself when a leaf is crushed.

Maybe there are strains of this far flung plant which differ in their scent characteristics?

Neutral htop On Jul 29, 2005, htop from San Antonio, TX (Zone 8b) wrote:

I have not grown thos plant so I am giving it a neutral rating.

Except in the extreme southern part, wafer ash is found throughout Texas. It can been found natively inhabiting a wide area in the United States including Arkansas, Florida, Louisiana, New York, Oklahoma and through the midwest, Arizona, California, Colorado and Utah. It grows in full sun to heavy shade, is adaptable to various soil types and ranges from dry rocky slopes to valley bottoms.

Classified as a shrub, it sometimes becomes a small tree growing to 18 feet. Its trifoliate leaflets vary in size and shape. The dark green, lustrous leaves may be alternate or opposite and in some varieties pubescent. The dioecious, small, yellowish blooms are somewhat fragrant; although, most of the other parts of the plant have a strong, pungent odor. The blloms appear from March to July. It has whitish to dark gray, bitter tasting bark. The wafer-like, 0.8 to 1 inch samaras (winged, dry, usually one-seeded fruit that does not open on its own to release seeds) ripen in August and September. They remain on the plant on drooping clusters through the winter. Wafer ash can be propagated by seed, grafting or layering. It is seldom used as a landscape plant/

It is a larval food for the swallowtail butterfly. The bark and the root have a number of medicinal uses. The fruit was employed as a substitute for hops in beer production. It has been cultivated since 1784. Now there are many varieties.

Positive peter_z On Jan 2, 2005, peter_z from St. Petersburg
Russia wrote:

Ptelea is hardy enough outdoors in St. Petersburg, Russia (=usda zone 4a). Here it looks like a shrub (2-4m height).

Neutral mystic On Sep 1, 2001, mystic from Ewing, KY (Zone 6a) wrote:

This is a small,deciduous tree or a large shrub depending upon where the plant grows.The bark and leaves are bitter, strongly scented. It has a straight, slender trunk, 68 inches in diameter,and seldom reaches a height of more than 20 feet.Has shiny,dark green leaves which turn greenish yellow in fall.The flowers are greenish-white and unpleasantly scented.This tree flowers in June.The fruit matures in September or October.The fruit is small,round, two-seeded,winged and pale green that stay on the tree over the winter.


This plant has been said to grow in the following regions:

Auburn, Alabama
Morrilton, Arkansas
Cordele, Georgia
Mcdonough, Georgia
Moscow, Idaho
Lisle, Illinois
Benton, Kentucky
Clermont, Kentucky
Georgetown, Kentucky
Lexington, Kentucky
Louisville, Kentucky
Nicholasville, Kentucky
Crowley, Louisiana
Richmond, Massachusetts
Roslindale, Massachusetts
Wellfleet, Massachusetts
Piedmont, Missouri
Erie, Pennsylvania
Austin, Texas (2 reports)
Fort Worth, Texas
Garland, Texas
Helotes, Texas
Marquez, Texas
New Braunfels, Texas
San Antonio, Texas (3 reports)
Cambridge, Wisconsin
Elmwood, Wisconsin

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