Ilex crenata ‘Sky Pencil’

(Question)

Hello,
I want to plant a row (4) of Ilex crenata in a strip of soil two feet wide for a length of six feet. This area does not get full sun–it gets partial sun, perhaps 4-5 hours in the morning and early afternoon, but none after 3-4 pm. I have read conflicting information regarding the amount of sun this plant needs. Also, I live in Toronto below the height of land, which places me in the warmer zone, I believe 5b. I have read conflicting information about the hardiness of this plant. The planting site is also against a neighbours verandah wall, so the plants would be shielded from the worst of winter winds. The soil is not sandy; given that I live in Toronto, I assume a clay-based soil, with non-acidic pH. I have not purchased any trees yet. Are they likely to survive in this spot?
Thank you,

(Answer)

Ilex crenata ‘Sky Pencil’, what a lovely plant.

I’m including a link to a very reputable source so you can get reliable information before you make such a large investment decision for your garden – see below.

https://landscapeplants.oregonstate.edu/plants/ilex-crenata

From the research I’ve done, I have some further information that may be useful.

  1. In order to have fruit, both male & female plants are needed.
  2. It is tolerant to most soils but needs good drainage.
  3. It is susceptible to aphids, scale, leaf miners and holly blight.
  4. Requires very little pruning to maintain its columnar shape.
  5. Grows in full sun to part shade.
  6. Requires one feeding in the spring of a 10-10-10 fertilizer.

The most pressing issue with this plant is its tolerance to our Toronto winter, will it survive & thrive?  According to the new Canadian Hardiness Zone map, Toronto falls into the 5a zone.  This means that plants should be hardy to temperatures between -26.1 degrees C to -28.9 degrees C.

According to the link above from Oregon State University, the plant is hardy to US Hardiness Zone 6 which means that it should be able to survive temperatures between 0 degrees F to -10 degrees F (-17 degrees C to -23 degrees C).

So deducing from the above information, I would say you are taking a chance if you purchase these plants because they just may not make it through our winters.

As an aside, I have checked with several nurseries here in Ontario and they are selling these plants with the Hardiness Zone as 7a which is equivalent to -15.0 degrees C to -17.8 degrees C, and will not guarantee them in colder zones.

I hope this makes sense and is helpful.