Densa Inkberry Holly: Tough, Versatile, Native Option

Image of inkberry holly. This shrub isn't beautiful, but it's practical.
Inkberry holly may not overwhelm you with its beauty, but its versatility may win you over. David Beaulieu

Taxonomic Classification of Densa Inkberry Holly:

According to plant taxonomy, this kind of holly is designated Ilex glabra 'Densa.' The third name in that string is the cultivar name.

Plant Type:

Inkberry holly is classified as a broadleaf, evergreen shrub.

What Inkberry Holly Looks Like:

 

This is a clump-forming bush with a broad, upright form. Female plants bear black berries (drupes). The leaves are a shiny, dark green.

The 'Densa,' 'Compacta' and 'Shamrock' cultivars are improvements on the species plant in the sense that their growth habit is more "dense" or "compact" and they're less prone to suckering. Densa inkberry holly is listed as reaching 3-4 feet tall at maturity (with a slightly greater width), although numerous people have reported sightings of specimens that have exceeded those dimensions.

 

Growing Zones for Densa Inkberry Holly:

Inkberry holly is native to Eastern North America, making it a favorite choice of native-plant enthusiasts. Densa is best suited to growing zones 5-9.

Prefered Growing Conditions:

Inkberry holly bushes can withstand a location in full sun in the North, but they also tolerate partial shade. As a plant whose habitat in the wild is wetlands, it's not surprising that they prefer an acidic soil, although they are not fussy about it. Indeed, their flexibility (see below) is perhaps their main selling point.

Uses in Landscaping:

 

Grown in a line, they are useful in landscaping property lines that are contiguous to busy streets, since they hold up well to the polluted conditions that are prevalent in such areas (see below). They are not, however, typically sheared into a tight, formal hedge, the way some of the other popular hedge plants are.

Likewise, group them loosely in informal mixed shrub borders to meet screening needs low-down that taller shrubs can't fulfill.

Grown in foundation plantings, they furnish reliable greenery all year long. And their shade tolerance makes them a fine selection for woodland gardens.

 

Care:

 

Prune or shear in late winter or early spring. Fertilize in spring with a fertilizer such as Holly-Tone. Other than that bit of care, inkberry holly is an excellent candidate for low-maintenance landscaping, which helps account for its popularity.

Hollies are either male or female. Densa inkberry holly is a female clone. Any male holly should be able to pollinate the flowers, which, apart from the berries they yield, are of little consequence.

 

Wildlife Attracted (or Not) to Inkberry Holly:

These shrubs are effective for drawing birds to the landscape. Wild birds will eat the black berries over the course of the winter. Luckily, the plants are not a draw for undesirable wildlife: they are deer-resistant and rabbit-resistant plants.

Alternate Common Name, Origin of the Names:

 

The primary common name, "inkberry" is an allusion to the color (black) of the berries. So is the secondary common name, "gallberry." The latter derives from the fact that black ink made from the galls of oaks was a perennial office staple long before there was a Staples.

Both Ilex glabra and Ilex coriacea go by the common name, "gallberry." The latter is sometimes distinguished from the former by being called "large gallberry." It is, indeed, the larger of the two, often being more tree-like in appearance. The specific epithet, coriacea is apt: "coriaceous" means "having a leathery texture," a reference to the leathery feel to the leaves of both Ilex glabra and Ilex coriacea.

The specific epithet, glabra means "smooth" and is also fitting, since inkberry hollies, in contrast to the more popular hollies associated with Christmas, bear soft, smooth leaves, not prickly foliage.

Meanwhile Ilex means "oak" in Latin. According to the Missouri Botanical Garden (MBOT), this is probably in "reference to the similarity of the holly leaf to the leaf of a Mediterranean oak known as Quercus ilex (holly oak)." Go figure: holly is named for an oak, which, in turn, is named after holly.

Ah, the wonderful world of plant names!

 

When Inkberry Shrubs Might Be a Better Choice Than Other Hollies:

 

There are many types of holly shrubs. Some are more attractive than inkberry holly, bearing bright red berries and leaves that assume the classic holly shape (i.e., with prickly edges). So one would be thoroughly justified in asking the question, Why would I plant inkberry bushes rather than another type of holly?

We don't make plant selection choices in a vacuum. Rather, plant A is selected over plant B because it's a better match for the particular location in question, with all of the challenges faced by the latter. So the better question is, Under what circumstances might inkberry holly be a superior choice?

A quick example that comes to mind is in swimming pool landscaping. A prickly holly may be fine in areas around the pool where you won't be walking much, but you wouldn't want to be brushing up against one with your bare legs on the way into or out of the pool. The soft leaves of inkberry would work better in the latter case.

But to answer the question in more detail, let's consider inkberry holly's less obvious strengths, chief among which are all the potential negatives that the plant tolerates. Inkberry holly is tolerant of:

 

  • Street pollution (including road salt)
  • Wind
  • Cold
  • Wet soil
  • Garden pests (including insects, in addition to deer and rabbits)
  • Plant diseases
  • Sea salt

 

The bush's tolerance of street pollution is one of the big reasons why, in Eastern North America, it is a mainstay in the landscaping for business establishments. I've seen them planted at many a shopping plaza. Because the sites for some businesses are open and thereby exposed to winds, inkberry holly's ability to hold up to strong winds also argues in its favor here.

I cite cold tolerance in the sense that its leaves tend to hold their green color better through winter than do some broadleaf evergreens (mountain laurels, for example).

Overly moist ground frequently poses a problem for homeowners.

Many landscape plants simply won't thrive there. As wet area plants, thanks to their swampy heritage, inkberry holly offers a solution in such spots.

The fact that inkberry holly is somewhat tolerant of sea salt gives you a second-rank option for a seashore landscape design.

All of this "toleration" means that inkberry holly gives you a lot of flexibility in planning a landscape design. This shrub may be the answer in a problem area where other candidates just won't grow well. What it may lack in beauty it makes up for in toughness and reliability.

Not that it is totally lacking in aesthetic value. The prickly-leaved hollies comport themselves stiffly, which is not always a desirable look. There may be corner of your landscape where you're seeking a softer, billowy look. Inkberry holly would fit the bill here.