Japanese Holly, Boxleaf Holly, Box-leaved Holly 'Sky Pencil'

Ilex crenata

Family: Aquifoliaceae (a-kwee-foh-lee-AY-see-ee) (Info)
Genus: Ilex (EYE-leks) (Info)
Species: crenata (kre-NAY-tuh) (Info)
Cultivar: Sky Pencil
Additional cultivar information:(aka Sky Sentry)



Water Requirements:

Average Water Needs; Water regularly; do not overwater

Sun Exposure:

Full Sun


Grown for foliage



Foliage Color:

Unknown - Tell us


6-8 ft. (1.8-2.4 m)


18-24 in. (45-60 cm)


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)

Where to Grow:

Unknown - Tell us


Unknown - Tell us

Bloom Color:

Pale Green

Bloom Characteristics:

Unknown - Tell us

Bloom Size:

Unknown - Tell us

Bloom Time:

Late Spring/Early Summer

Other details:

Unknown - Tell us

Soil pH requirements:

6.1 to 6.5 (mildly acidic)

Patent Information:

Unknown - Tell us

Propagation Methods:

From softwood cuttings

Seed Collecting:

Remove fleshy coating on seeds before storing


This plant is said to grow outdoors in the following regions:

Mobile, Alabama

Burbank, California

Mission Viejo, California

San Diego, California

San Jose, California

Fort Pierce, Florida

Danielsville, Georgia

Rincon, Georgia

Peoria, Illinois

Evansville, Indiana

Gretna, Louisiana

New Orleans, Louisiana

Vacherie, Louisiana

Nottingham, Maryland

Lucedale, Mississippi

Warrenton, Missouri

Brooklyn, New York

Franklin Square, New York

Massapequa, New York

Broadway, North Carolina

Charlotte, North Carolina

Davidson, North Carolina

Elizabeth City, North Carolina

New Bern, North Carolina(2 reports)

Raleigh, North Carolina

Canton, Ohio

Cincinnati, Ohio

Sandusky, Ohio

Williamsburg, Ohio

Enid, Oklahoma

Tulsa, Oklahoma

Cheshire, Oregon

Bethlehem, Pennsylvania

West Chester, Pennsylvania

Williamsport, Pennsylvania

Bristol, Rhode Island

Chesnee, South Carolina

Culleoka, Tennessee

Germantown, Tennessee

Copperas Cove, Texas

Crowley, Texas

Harker Heights, Texas

Irving, Texas

Newport News, Virginia

Anacortes, Washington

show all

Gardeners' Notes:


On Aug 29, 2021, Clint07 from Bethlehem, PA wrote:

In the semi-shade of Zone 6 I planted four of these. After they started looking a bit sick (some leaves yellowing and dropping), I tested the soil. It came back pH 7.7. According to state extension hollies like pH 5.5. I treated the soil with elemental sulfur and chelated iron, which brought them back somewhat. Then I neglected them for a couple of years and they dropped a lot of leaves. Chelated iron is said to help them both as a foliar application and in the soil. I still admire rows of columnar shrubs and trees of any sort and size; it's a popular landscape installation.


On Jul 2, 2019, 1amore1 from San Diego, CA (Zone 10a) wrote:

I planted these Sky Pencils (3 of them) in Nov 2017 and I believe I'm not in the ideal growing zone (zone 10) but they seem to be doing fine. I have them planted along a south side wall of my yard. They sometimes get some browning leaves that fall off but other than that I love they way the look since I needed a vertical accent.


On Dec 26, 2018, JennysGarden_TN from Collierville, TN wrote:

This is a grow and forget about it plant in my zone 7b sunny garden. I have two of them. I just let them grow and do their own thing. They get mostly rainwater.


On Jun 3, 2014, wildbarrett from Lakewood, OH wrote:

Planted in a slightly raised bed with very good drainage, along with other Japanese Holly variants. Established well, lovely shrub, and after 3 years flourishing and growing...Suddenly did not make it through this rather harsh winter Northern Ohio 2013-2014 and must be removed. Lost the columnar Soft Touch form of the Japanese Holly as well, although it had flourished too. Heartbreaking! Whole bed must be dug, brown guys tossed, and bed redesigned. Costly and a waste of time and effort with these, sadly!! I also had a young "nursery" of the Sky Pencils in another location, again, growing beautifully for 3 full years and exceedingly protected from wind and snow. Same thorough damages, so I believe the problem was due to not so much the temperatures, but the prolonged cold. We did not have a... read more


On Jan 17, 2013, Fires_in_motion from Vacherie, LA (Zone 9a) wrote:

This site's height rating is way off; I've seen them up to 25-30 feet tall. A superior new (native) alternative is a tall, narrow yaupon holly hybrid called Ilex 'Scarlet's Peak.'


On Jul 19, 2012, gshrine from Indianapolis, IN wrote:

I LOVE the look of this plant so I planted one last fall in mostly sun, by spring after a very mild winter it was looking a touch brown. Still I bought 4 more in the spring, 3 planted in slightly more shade (afternoons) and 1 planted in full on sun. All are dead now just a few months later, the full sun one lasted a few weeks longer than the others. I watered almost daily and this was before the cripling heatwave. I've never lost so many plants so quickly. I'm going to try pillar barbery instead.


On Jun 26, 2012, HangNail from Hurst, TX wrote:

Planted ten Sky Pencil Holly in south facing flower beds.

First planting of all five died.

Planted five more 03/2012. Two died so far.

One branch dies, followed by remaining branches.

Local DFW nurseryman does not recommend for DFW, and will not sell them. Says not as hardy as advertised, and disease prone. Although larger, suggested Will Fleming Holly.


On Jul 29, 2010, rkwright85 from Horton, MI (Zone 5b) wrote:

This is a very neat plant especially in containers and rock gardens. It's very marginal where I live (zone 5b) and burns easily if exposed to any afternoon sun and wind in the winter.


On Mar 30, 2009, mer201 from North Bergen, NJ wrote:

Here in northern NJ I planted a Sky Pencil that suffered a serious case of winter burn on one side. Most of the plant is green, but a large section turned completely brown and died. It was a new planting last fall, and we had a very tough winter this year. I have turned it around so that the remaining good side faces out, but this plant should probably be planted in spring to give it plenty of time to take. I think I will also Wilt-Pruf it next winter as well.


On May 27, 2008, danludwig from Cincinnati, OH wrote:

Saw & bought one of these at a local greenhouse last fall. Planted it in September to hide a gutter downspout and it survived the winter (Cincinnati, zone 6, barely). I like it so much that I bought 3 more this spring (1 to balance the first at the other end of my yard, and 2 to flank the front door).

From everything I can gather, these sky pencils are females. Wish I could find a male to sex them up so they will flower in spring and make berries in fall. However, I can't seem to find out exactly what kind of male holly (or hollies) will fertilize them.


On Dec 9, 2006, claypa from West Pottsgrove, PA (Zone 6b) wrote:

Trademarked as 'Sky Sentry' in Canada. Introduced by the US National Arboretum in 1985


On Apr 11, 2006, Sheila965 from Rincon, GA (Zone 8a) wrote:

I purchased this plant for my pond area. I live in Zone 8. I've seen it around town so I'm hoping it will live through the winter. It's very beautiful and within two weeks, it already has lots of new green growth on it.


On Oct 5, 2004, TXMel from Fort Worth, TX (Zone 7b) wrote:

We have a pair of these planted on either side of our front door. They have been there for 6 years, and except for yearly trimming their height, they are very low maintenance. I don't know how tall they would be if we let them grow, but now they are contained at our eaves, which are about 10' high. They give a great look of tall Italian Cypress, here in our Texas heat! They are on the West side of our home, and get plenty of sun.


On Mar 10, 2004, Terencetrent from Arlington, TN (Zone 7a) wrote:

This is a very low-maintenance and slow growing plant that provides good a vertical appearance to bed locations. Foliage remains green throughout winter.


On Aug 5, 2003, Laural from Madison, GA (Zone 7b) wrote:

This is terrific for "bones" in a small garden. It grows well here,(zone 7 Georgia) in acid soil and high filtered to dappled shade.It is very easy to manage as it grows slowly and vertically, which means it doesn't have to be pruned or moved when it starts to crowd others. Very polite shrub!I'm very pleased with them.