Landscaping Design: Hop Tree

Monday, March 3, 2014

Hop Tree

Ptelea

A small genus with only 15 species of trees or shrubs native to North America and Mexico.
Prefers full to partial sun ( partial sun is best in climates with hot summers ).
Propagation is from seed or layers. Cultivars can be propagated from softwood cuttings taken during summer.

Ptelea baldwinii
A large shrub to 15 feet that is native to the southwest U.S. It sometimes becomes a tree, especially if pruned as such; the largest on record is 27 x 20 feet with a trunk diameter of 15 inches.
The foliage is trifoliate with all 3 leaflets the same size to 2.5 inches in length.
The leaves are covered in fine hairs at first and turn to bright green in summer then to bright yellow in autumn.
The pale green flowers are followed by winged fruit that is up to 0.7 inches in width.
The bark is whitish.
Hardy zones 6 to 10

Ptelea crenulata
A large shrub to 15 feet that is native to California. It can be trained to grow as a small tree, the largest on record is 22 x 13 feet with a trunk diameter of 1.5 feet.
The leaves are trifoliate with 3 finely serrate leaflets up to 5.5 inches in length.
The foliage is bright green and borne on a leafstalk up to 3 inches long.
The bark is smooth.
Hardy north to zone 7

Ptelea trifoliata ( Common Hop Tree )
A moderate growing, small tree with a dense, bushy, rounded crown, reaching up to 20 feet or more, that is native to the central U.S. from Nebraska to Ontario to Massachussetts, south to Mexico to northern Florida. It is endangered in its native range in Ontario, Canada.
Some records include: fastest recorded growth rate - 10 feet ( stump sprout ); largest on record - 50 x 32 feet with a trunk diameter of 1.5 feet.
The leaves are composed of 3 oval, mostly smooth margined leaflets with the central one, up to 4 or rarely to 6 inches in length being the largest. The aromatic foliage is semi-glossy and medium green above and paler below. They turn to bright yellow in autumn.
The very fragrant, greenish-white, starry flowers are borne in terminal clusters in early summer.
The flowers are fragrant and smell like orange blossom.
They are followed by beige color, papery winged fruit up to an inch wide that persists late into fall. Hop Tree is structurally tough and sturdy.
The twigs are stout and aromatic.
The gray bark is thin and warty.
Hardy zones 2 to 8 on fertile, well drained soil. It is hardy far north of its native range and even survives as far north as Saskatoon, SK and Lenningrad, Russia.
Tolerant of sandy soil, it is sometimes found on sandy dunes in the wild.

* photos taken on August 3 2010 @ University of Guelph Arboretum, Ontario