Castor Aralia, Castor-Aralia

Kalopanax septemlobus

Family: Araliaceae
Genus: Kalopanax (kal-OH-pan-aks) (Info)
Species: septemlobus
Synonym:Kalopanax pictus
Synonym:Acanthopanax ricinifolius
Synonym:Acanthopanax septemlobus



Foliage Color:

Unknown - Tell us

Bloom Characteristics:

This plant is attractive to bees, butterflies and/or birds

Water Requirements:

Average Water Needs; Water regularly; do not overwater

Where to Grow:

Unknown - Tell us


over 40 ft. (12 m)


over 40 ft. (12 m)


USDA Zone 4a: to -34.4 C (-30 F)

USDA Zone 4b: to -31.6 C (-25 F)

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)

Sun Exposure:

Full Sun


Parts of plant are poisonous if ingested

Bloom Color:

White/Near White

Bloom Time:

Mid Summer


Grown for foliage


Other details:

Unknown - Tell us

Soil pH requirements:

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)

7.9 to 8.5 (alkaline)

Patent Information:


Propagation Methods:

From seed; direct sow outdoors in fall

From seed; winter sow in vented containers, coldframe or unheated greenhouse

From seed; stratify if sowing indoors

Seed Collecting:

Properly cleaned, seed can be successfully stored


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

Palmetto, Georgia

Evanston, Illinois

Maple Park, Illinois

Monticello, Illinois

Roslindale, Massachusetts

Helena, Montana

Fairport, New York

Lyndonville, New York

Medina, New York

Syracuse, New York

Cottage Grove, Oregon

show all

Gardeners' Notes:


On May 8, 2014, rickc304 from Niles, OH (Zone 6a) wrote:

This is a very attractive, unique tree which provides a tropical feel but is winter hardy. It is attractive throughout the year with lush foliage and an interresting winter appearance to the twigs and bark. In the landscape it makes a great specimen tree adding an unusual touch of the tropics to northern gardens.


On Jan 21, 2014, coriaceous from ROSLINDALE, MA wrote:

I live in Boston near the Arnold Arboretum, where this tree produces tremendous numbers of seedlings.

I have observed this tree spreading rapidly into the surrounding neighborhoods and several miles into the suburbs beyond. It produces vast quantities of seeds which are effectively distributed by birds. Its behavior has been so alarming that, despite its rarity, it has become a plant of concern to many organizations concerned with the preservation of natural areas.

This tree is very thorny. Many people are reluctant to weed out the seedlings because they're so formidably armed.


On Nov 7, 2012, Billy2421 from Doncaster
United Kingdom wrote:

Hi all

I recieved my seeds today that i orderd from the USA. I live in the UK and need some help with germination of the seed.

1. Do i need to strarify the seed(cold-hot) and for how long.

2. Could i just propigate as normal in a propigator.

3. Do i need to pre-soak the seed and maybe rub over some sand paper.

I have searched the internet and have seen conflicting information on growing from seed.
Thank you for your help.
Billy (UK)


On May 18, 2011, msannthorpe from Evanston, IL wrote:

Three of these have popped up in my yard uninvited, and it looks like they germinated over a two-year period. I've seen a couple of others around the neighborhood, too. It's definitely an interesting-looking tree, but I'm wondering if it might be one of the next great invaders.


On Apr 19, 2011, delbertyoung56m from Medina, NY wrote:

I planted three seeds that I got from Smiths Pond in Lyndonville, NY from a mature and lovely tree which is beside the pond and near Platton Rd. All three seeds have thrived in my Yard on State St in Medina, with one of them planted between curb and sidewalk so that all can enjoy the beauty of the rather sweet gum-like leaves. All are over 6 ft tall, with one being slightly over 15 ft tall since planting in 2001. The stout thorns make them rather interesting to look upon. I was first introduced to this tree when stationed in Seoul, South Korea in 1995, and saw the trees growing wild on Namsan Mountain.


On Nov 19, 2006, lkz5ia from Denison, IA (Zone 5b) wrote:

Bought a little plant last year and it died to the ground. It came back this year. But I gave it a positive because I think it'll become one of my favorite trees. I love the large leaves it has and also the thorns that cover the stem.


On Apr 17, 2005, passarb from Syracuse, NY wrote:

This tree is not grown commonly in the Syracuse area. Two specimens at Pass Arboretum reputed to be the only K pictus in the city. Both have been severely damaged from storms.
Foliage very unusual and ornamental.
Staff at the Arnold Arboretum, Boston have complained that it is a nuisance. Thorns on naturalized 'volunteers' make removal difficult.
Plus and minus.
I'll try to find pictures of the foliage.