Much of the southeast is experiencing a growth spurt. The latest statistic I heard from my own area of South Carolina is that an average of 29 people move to Spartanburg County every day. New subdivisions are appearing on what was once farmland. With residential lots getting smaller and houses getting closer together, many homeowners are seeking narrow, evergreen shrubs for their gardens. Sky Pencil holly (Ilex crenata 'Sky Pencil’) seems like a perfect choice for a narrow hedge or property line marker.
Members of the holly (Ilex) family are known for their ease of culture. With attention to a few conditions, Sky Pencil can be an excellent, low maintenance choice. It grows slowly so will not get overgrown in a short time. If left unpruned, Sky Pencil will eventually reach a height of eight to ten feet, with a width rarely exceeding one or two feet. It prefers an acidic to neutral soil, and full sun to part shade. In hot areas, a little afternoon shade helps avoid sunburn resulting in yellowing and leaf drop. It is adaptable to most soil structures from sand to clay. It will not tolerate alkaline soil, drought, or constantly wet conditions. Sky Pencil is winter hardy in zones 5-8. Provide protection from cold winds, and mulch around the base to provide insurance against frost heaving or competition from weeds. To keep Sky Pencil hollies looking their best, prune the tops of the tallest branches once or twice during the warmer months to maintain a uniform appearance.
There is a downside to Sky Pencil. It can be a reverse ugly duckling, looking beautiful in its youth but developing some unattractive behavior as it gets older and taller. After shrubs reach six feet, they tend to separate and spraddle at the top. Ice storms or wet snow can also make them splay out like a mop head. Some gardeners wrap fishing monofilament line around the tops of these shrubs to corral the spreaders. Please do not do this. The line will eventually cut into the branches and result in limb death. If a winter ice storm is forecast and you want to protect your plants, circle the tops with soft, stretchy material (old pantyhose or tights work well) and remove the restraint as soon as weather danger has passed. Unless your soil is devoid of fertility, I would bypass the addition of fertilizer. It will hasten the vertical growth, yes, but it will also hasten the possibility of top separation.
Young Sky Pencil hollies can fulfill the “thriller” role in containers without crowding out companion plants. They can also be used in small formal gardens to provide a vertical feature when other fastigiate plants might be too broad for the space. Example: Fastigiate upright plum yew (Cephalotaxus harringtonia fastigiata) makes a super focal point in landscape borders, but with time it will grow to five feet wide.
So, what do you do when the perfect plant becomes perfectly ugly? The same thing you do with Rosemary when it changes from an attractive, aromatic shrub into a woody, ugly thing: remove it and replace it with a younger model of the same plant.
