Japanese Zelkova

Basic Information
Tree ID: 
Genus and species: 
The Japanese zelkova, is a deciduous tree that typically grows to a height of around 30m. It typically has a short trunk followed by many erect branches that continue upwards to create a round-topped head. You can differentiate these trees from an American Elm due to the Zelkova's unwinged fruit and symmetrical rather than uneven leaves.
Taylor Cogsil and Shannon Conneely
Collected Data
Tree shape: 
Date of tree entry: 
12.10 m
Diameter at breast height: 
0.27 m

The bark is typically grayish-brown/grayish-white and has lenticels. When there are exfoliated patches, the orange inner bark is revealed.
Twigs & branches
Its twigs are typically thin and have small, dark conical buds in zigzag patterns. The branches tend to be glabrous.
The branches contain leaves that can grow up to 5 cm long and wide and have an oddly pinnate arrangement. These leaves are simple, ovate, and have serrated or crenate margins, which is why the tree has the species name serrata. Each leaf typically contains 8-14 pairs of veins. The leaves are rough on top and basically smooth underneath. They are green in spring and throughout the summer, but change to yellow, orange and red during fall. All leaves are lost during the winter. The petioles are 2–5 mm long.
Reproductive Structures
The tree has hermaphroditic flowers that bud in the spring. Buds emerge at a 45 degree angle from the stem and are egg-shaped with dark brown scales. The staminate flowers grow to be about 3mm in diameter and cluster in the lower leaves. The pistilate flowers are about 1.5mm in diameter and are found mostly in the upper leaves. In bloom, the flowers are yellow-green and are clustered along new stems. Eventually they become small, ovate drupes as fall arrives. The drupes are originally green but darken to brown and are about 2.5 to 3.5 mm in diameter.
The fruit of the Zelkova serrata is oval shaped, and less than a half inch in length. Its covering is dry or hard, and it does not attract wildlife as it is inconspicous.
  • Zelkova Serrata: Fall - http://www.greatplantpicks.org/images/zelkova-serrata-jfssc-01-gpp1.jpg
  • Summer
  • Winter
Natural range of distribution: 
Map of the Natural Range of Distribution: tpittaway.tripod.com The Zelkova serrata is not native to North America, although it has replaced the American elm because it is resistant to the Dutch elm disease. Its natural habitat is in Asia, specifically Japan, Korea, Taiwan and eastern China. These trees do not fare well in drought, cannot survive in shade, and die if temperatures drop below -33 degrees Farenheit.
Origin, history, and uses: 

The Zelkova serrata is traditionally used in Bonsai, but because of its hardiness, it has been adapted for many other uses. It buffers street corners and parking lots and it has become a successful urban tree because it can survive in areas with air pollution and hard soil. In addition, Zelcova serrata usually does not have surface roots and it is pest resistant. It also provides good shade and is easy to clean up in the fall. 

The first instance of cultivation outside of Eastern Asia was in the Netherlands in 1830 when Phillip Franz von Siebold relocated the species. 

The tree grows each year during the spring and summer. The tree blooms in mid spring and then produces fruits with seeds during the summer and fall. Though the abundance of seeds is high, the spread of the fruit and seeds is very slow. The reproductive season of the tree ends when its leaves turn from green to yellow to red and are eventually dropped, but cold stratification is not necessary for the germination of seeds.
Other information of interest: 

A fun fact is that this species was recently awarded the Royal Horticultural Society’s Award of Garden Merit for high quality as a garden plant. 

Media and Arts
Creative Project

The Fresh Prince of Hillhouse:

Now this is the story all about how

Marta saw me and raised her brow

“You’ll be in Yale Nature Walk if there’s a way.

Gotta assign you to Shan and Tay”

In West New Haven

Planted and raised

On High Street, where I spent most of my days

Chillin out maxin relaxin all cool

And getting fertilized outside of the school

When a couple of oaks,

That were up to no good

Started making trouble in my neighborhood

I got in one little fight and my mom got scared

And said, “you’re moving to Hillhouse with the students of Yale!”

Tour groups stroll by and when they come near

They look me up and down from front to rear

If anything I could say that they’re over zealous

I’ve been accepted at Yale, I think they’re jealous

Lab came by in the winter, ‘bout 7 or 8

Shook their heads as they left and said, “Why’s spring so late?”

But I looked at my students

They were finally here!

Shan and Tay were ready to get A’s for the year