Description & Overview

Hop Tree is a long-lived Wisconsin native with variable shape and a dense, broad canopy. The dark gray-brown bark is quickly overshadowed in the spring by glossy green leaves that give off a lemon-like scent when crushed. Flowers, smelling similar to orange blossoms, appear in June followed by bundles of papery samaras that ripen in the fall and persist through the winter.

Hoptree may also be known as Wafer-ash or Stinking Ash.

Core Characteristics

Category: Tree

Wisconsin Native: Yes

USDA Hardiness Zone: to zone 4

Mature Height: 15-20 feet

Mature Spread: 15 feet

Growth Rate: Slow

Growth Form: Small Tree, Large Shrub

Light Requirements: Full Sun to Full Shade

Site Requirements: Well - drained, dry to moist sites. Adaptable to a wide range of soils.

Flower: Inconspicuous ¼" greenish - white flowers appear in clusters in June - smells like orange blossom although some may find the smell unpleasant/musky.

Bloom Period: Early Summer, June

Foliage: Glossy, green. Pointed at the tips. Technically, leaves are made up of three leaflets. Each leaf can get to 4" - 6" in length and whencrushed leaves are aromatic, slightly lemon - like, andor musky. Leaf scars are U - shaped.

Fall Color: Yellow

Urban Approved: Yes

Fruit Notes: Samaras are ¾" - 1" long and arepale yellow - brown, papery, flattened, and winged. Fruit ripens in September - October and persist through winter.

Suggested Uses

Hoptree is typically found in calcareous soils in southeastern Wisconsin in oak forests, dry prairies, rocky slopes, or along rivers. You can see this small tree along the banks of Lake Michigan in Milwaukee as it is commonly found in well-draining sites adjacent to waterways.

Restoration: This tree can adapt to a wide range of soils and can handle a varying amount of sunlight, ensuring that it will do well in many different sites. If you have an area recently cleared of Buckthorn, whether in the understory or full sun, Hoptree would be a good choice. A natural setting, such as a park or wildlife area, where it is allowed to grow to its truest form would be best.

Erosion: With its tolerance of many soil types and suckering habit, Hoptree is a solid choice for erosion control where its deep roots would help in stabilization.

Screening or Hedge: A dense canopy ensures good screening capabilities. Although it suckers, the growth rate is slow enough that it would be manageable in a landscape setting. Be aware that Hoptree is not tolerant of salt.

Hop Tree is a long-lived Wisconsin native with variable shape and a dense, broad canopy. The dark gray-brown bark is quickly overshadowed in the sprin…
Hop Tree is a long-lived Wisconsin native with variable shape and a dense, broad canopy. The dark gray-brown bark is quickly overshadowed in the sprin…
Hop Tree is a long-lived Wisconsin native with variable shape and a dense, broad canopy. The dark gray-brown bark is quickly overshadowed in the sprin…

Wildlife Value

Flowers emit a fragrance that while rather stinky to humans is intoxicating to pollinators such as bees and butterflies. Hoptree is largely pollinated by short-tongued bees, wasps, flies, and butterflies.

Hoptree is a host plant to the Easter Tiger Swallowtail and is one of the few host plants in Wisconsin for North America’s largest butterfly-the Giant Swallowtail. Look for the orange eggs on the upper surface of the leaves; they give rise to larvae that are camouflaged to look like bird droppings! In case you are curious, the only other Wisconsin native that is a host to the Giant Swallowtail is Prickly Ash, which is also available at Johnson’s Nursery.

The fruit, wafer thin and papery and hanging on well into winter, is eaten by wildlife includingsongbirds such as Song sparrows, and small mammals like squirrels.

Maintenance Tips

Maintain a proper mulch ring to help keep roots at a consistent moisture level. Supplemental watering is helpful in times of drought. There is no need to fertilize with typical, average soils.
Prune out suckers to maintain stature.

Hop Tree is a long-lived Wisconsin native with variable shape and a dense, broad canopy. The dark gray-brown bark is quickly overshadowed in the sprin…
Hop Tree is a long-lived Wisconsin native with variable shape and a dense, broad canopy. The dark gray-brown bark is quickly overshadowed in the sprin…

Pests/Problems

Black Walnut Tolerant: No
Deer Resistant: Yes
Rabbit Resistant: Yes

No serious pests or diseases.

Leaf Lore

The genus name, ‘Ptelea,’ is Greek for ‘Elm,’ honoring the fruit it bears and its similarity to elm fruit.

Hoptree is one of the few plants in the Rue family (Rutaceae) that are native to Wisconsin. The Rue family notably contains citrus fruits, such as oranges, lemons, limes, grapefruits, and more. It also contains our native Prickly Ash (Zanthoxylum americanum).

When young, the leaves could be mistaken for Poison Ivy as both have three leaflets. On Hoptree, the terminal leaflet is narrow and V-shaped at the base with a very short leafstalk. Poison Ivy has a terminal leaflet with a long leafstalk as well as a rounded base.

The seeds of the Hoptree have been used as a substitute for the hops traditionally used to make beer, due to their similar bitter taste.

Historically, Hoptree was used by Indigenous peoples as an adjuvant, an additive to other medicines to increase potency, and the pounded root as a pulmonary aid.

Hoptree is monoecious, meaning that it produces male, female, and perfect (one flower, but with both male and female parts) flowers. This means it is self-fertile.

Companion Plants

Blackhaw Viburnum (Viburnum prunifolium), Eastern Redbud (Cercis canadensis), Gro-low Sumac (Rhus aromatic ‘Gro-low’), Glossy Black Chokeberry (Aronia melanocarpa var. elata), Hairy Penstemon (Penstemon hirsutus), Bladdernut (Staphylea trifolia), Upland White Goldenrod (Solidago ptarmicoides), and Lady Fern (Athyrium filix-femina) would all complement Hoptree.

Hop Tree is a long-lived Wisconsin native with variable shape and a dense, broad canopy. The dark gray-brown bark is quickly overshadowed in the sprin…
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Written by Beth DeLain