A Gardening Journal

The Best Season Ever: Gold-leaved "Blue" Holly

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Bright foliage can be cheering in any season. As part of the show in Spring and early Summer—when the new season already makes the entire garden a fresh experience—colorful leaves are the epitome of exuberance. The glowing gold foliage above is that of a rare holly, Ilex x meserveae 'Gretchen'. She belongs in almost any garden where she's hardy.

 

The thick leaves are prickly but not painful. The meserve hollies are a pleasure to work with, requiring none of the protective long sleeves and gloves that you need when handling many American or English hollies. 

 

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Even after thirteen years, my specimen is still in its gawky adolescent phase: 'Gretchen' is much slower growing than other meserve hollies. 

 

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The new foliage of the season is the brightest by far. In the picture below, you can tell how much greener last year's foliage has become. See "How to handle it: Another option—or two!" for options that maximize the production of new foliage?

 

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Here's how to grow this striking but rare holly:

 

Latin Name

Ilex x meserveae 'Gretchen'

Common Name

Gold-leaved "blue" holly

Family

Aquifoliaceae, the Holly family.

What kind of plant is it?

Broadleaved evergreen shrub. Hollies keep the sexes separate; 'Gretchen' is a female. 

Hardiness

Zones 5 - 9, but with caveats: In eastern North America, exposed bushes can suffer defoliation above the snow line in Zone 5; there's no danger of that in Zone 6a and warmer. In Summer, heat and humidity limit the vigor of meserve hollies in Zones 7 to 9, but there's a torrent of other dense broadleaved evergreens to choose among, anyway: See Ilex 'Nellie R. Stevens' as well as the many cultivars and species of Osmanthus. Only in the cool-Summer coastal West Coast could meserve hollies thrive to Zone 9. But there, too, there are so many other options for broadleaves—not least, Ilex aquifolium itself—that there's little call for the meserves. They are at their best, and most needed and loved, from Missouri to Maine.

Habit

Multi-stemmed. Usually matures to a broad mound with well-foliaged branching of ground-covering density.

Rate of Growth

Slow to medium.

Size in ten years

I'm unaware of fully mature specimens of 'Gretchen'. My sense is that this cultivar is less vigorous than is typical for blue hollies: Possibly six to eight feet tall and wide, instead of twelve to fifteen feet. I planted mine in 2000, as a small cutting-grown starter. It is just five feet tall.

Texture

Full, dense, and heavy, even when growing free-range, where a looser branching pattern is normal. When pruned with any regularity—see the second "How to handle it" box, below—Ilex x meserveae hybrids acquire the solidity and rigidity of architecture formed from plants: "Hortitecture," perhaps.

Grown for

its colorful foliage: The leaves of new growth are pure yellow-green, and mute only partially during Summer and Fall. By their second year, they are mid-green. They never darken to the deep blue-green of classic blue hollies such as 'Blue Princess'. 

 

its berries: Hollies that are pruned bear few berries; see "Quirks and special cases," below. If 'Gretchen' is allowed to grow free-range—and is provided with a suitable male pollinator, such as 'Blue Prince'—red berries are produced. They are a striking contrast to both the yellow first-year foliage and the medium-green leaves formed in prior years.

 

its ease of handling: Hollies accept pruning without complaint. See "How to handle it: Another option—or two!" for some possibilities.  

Flowering season

Holly flowers are small and white; they are fragrant as well as numerous, but not showy. Flowering is in mid-Spring; flowers of 'Gretchen' form on second- and third-year growth, not that of the current season. 

Color Combinations

The yellow new foliage of 'Gretchen' retains enough green that it can harmonize with just about any other color, from red and orange, to pink and purple, to yellow and cream. Its intensity is greatest in Spring and early Summer, muting but not disappearing as Summer progress to Fall and Winter. 

The red berries are prominent from late Summer into Winter, when the yellow foliage is comparatively calm.

See "Plant Partners," below, for combinations that take advantage of the shrub's seasonal foliage cycle (really yellow in Spring, muted yellow the rest of the year), and the seasonal berry cycle (no berry display from late Winter through mid-Summer, full display late Summer through mid-Winter).

Partner Plants

'Gretchen' is at its most vividly yellow from Spring to early Summer, when the season's new growth emerges and enlarges to its full length and bulk, but has not yet started to mute during the Summer heat. During that time, near neighbors whose coloring is dark and even funereal would provide the maximum contrast. In addition to the ideal backdrop—dark green—of yew (or, as in my pictures, a vertical form of plum yew), plants whose foliage achieves darkness via the burgundy and ebony routes would be especially dramatic.

 

Handily, a number of plants with such coloring also peak in early Summer. Gardeners in Zones 7 and 8 should consider establishing one of the purple forms of Phormium on one side of 'Gretchen', and a colony of Disporum cantoniense 'Night Heron' on the other. Hardier choices include Cotinus coggygria 'Velvet Cloak', Ophiopogon planiscapus 'Nigrescens', Physocarpus opulifolius 'Summer Wine', Rodgersia pinnata 'Chocolate Wings', and Weigela florida 'Summer Wine'. The foliage of purple beeches is also at its darkest when that of 'Gretchen' is at its brightest, as are the shiny "dipped in pitch" young leaves of Osmanthus heterophyllus 'Purpureus'. The leaves of black-leaved catalpa are perhaps the darkest of all; their matte finish compounds the impression that they are not so much dark, per se, as they are light-absorbing: They are the foliar equivalent of a black hole. Catalpas accept coppicing without hesitation, which would bring the branches and foliage of Catalpa x erubescens 'Purpurea' in range of that of 'Gretchen. 

 

Because holly flowers are only modestly showy, even a shrub in full flower functions mostly as a foliage plant. So, there's plenty of welcome for neighboring plants whose early Summer flowers are the vehicle for the dark shades that contrast best with 'Gretchen'. Iris would be a particular thrill, in that dark-petaled varieties sometimes display contrasting details of yellow in their beards or in the pigment pattern of the petals. Almost all of them flower in Spring or early Summer, when 'Gretchen' is at its peak. Iris louisiana 'Black Gamecock' is only the most readily-available option; visit the site of a specialist, such as Ensata, to dive deep into lists of less well-known options. Other floral possibilities include Alcea rosea 'Nigra', Clematis 'Romantika', Paeonia delavayi, Rosa 'Souvenir du Dr. Jamain' and—if you can ever find plants, and provide the moist soil the species needs—Veratrum nigrum.  

 

By late Summer, the show of 'Gretchen' shifts from yellow foliage—which by now is muted, anyway, and whose bright presence has long since changed from a Spring surprise to the normal complement of the season's garden colors—to red berries. The plants listed above that bring burgundy coloring through foliage instead of flowers could coordinate equally well. The Fall foliage of the Physocarpus is, surprisingly, even more saturated and colorful than it is in Summer; its ability to combine with red berries is heightened as well. Countless dahlias have berry-red petals, and the semi-single forms bear yellow disk flowers that call out to the foliage of 'Gretchen'. Avoid siting other plants with showy berries nearby; the juxtaposition only invites judgmental comparisons of whose berries are darker, bigger, or more numerous. 

Where to use it in your garden

'Gretchen' can handle the usual assignments of blue holly: informal screening or pruned hedges, plus free-range mounds and banks in larger landscapes. This cultivar is much smaller at maturity than is typical for a blue holly, so 'Gretchen' is more suitable for compact gardens. 

 

Because of its unusual seasonally-changing foliage, which is more profuse and, therefore, colorful in response to pruning, 'Gretchen' can also merit more focal use. What about as clipped mounds marking off segments of a large mixed border? Or cones scattered across a lawn? Or a single, obsessively-clipped obelisk at the center of a compact townhouse garden?

Culture

As is typical for hollies, 'Gretchen' prefers acidic soil with a generous amount of organic matter, reasonable drainage, and freedom from drought stress. Partial shade is tolerated, although growth is slower and not as dense. Full sun is best.

How to handle it: The Basics

If you garden in Zone 6 or colder, plant only in Spring. In Zone 7 and warmer, Fall planting is fine, too. You'll probably not be able to find plants larger than small starters, or even rooted cuttings. If so, be attentive their first season, ensuring enough water for establishment, spraying with antidessicant on a "warm" (above 40 degrees Fahrenheit) day in late Fall or early Winter, and mulching thickly. Allow plants to grow freely for a year or two. If free-range growth is the goal, formative pruning isn't usually needed. If you can't resist some pruning, encourage additional bushiness by cutting back the tallest stem tips by a foot in late Winter. 

How to handle it: Another option—or two? 

New foliage is the most brightly colored, so pruning—which encourages sprouting of additional stems farther down the branch—is always tempting. Succumb! Prune in late Winter or early Spring, as severely as you want: Hollies resprout from even the most draconian cutting-back, even to the base of the largest branches. Refrain from any further pruning that season until the cool temperatures of Fall; pruning in Summer is likely to encourage new growth that will not have enough time to harden sufficiently before Winter. 

 

To create a pruned 'Gretchen' hedge, plant as closely as you can. If you can locate enough young stock, space the small plants eighteen or even twelve inches apart. Site so that the entire hedge receives the same conditions of soil, drainage, and sun, so that growth is even and vigorous from end to end. Let the young plants grow free-range for a couple of years, then, in early Spring, lightly prune side growth so that the center of gravity of the hedge is low and concentrated on the center line. Dense broadleaved evergreens will hold large amounts of snow, which can become heavy enough to splay branches apart from the mass, or even break them. As the hedge matures, prune without mercy such that the width of the hedge decreases with height; strive for a cross-section of a tall and narrow pyramid. This profile doesn't just allow sun penetration from top to bottom, ensuring maximum density of growth. It also minimizes the amount of horizontal surface and, so, reduces the risk of excessive snow accumulation and damage.

 

To establish a dome of 'Gretchen', keep in mind that dense side growth right to the ground is essential. Clip higher branches of adolescent bushes back by half in Spring, while pinching just the soft tips of the remaining lower branches. As the mound's desired width is established, reduce the extent of pruning of the central upward-growing branches, so that the overall shape can progress from an English muffin to a true mound. For quicker maturity, especially of a mound whose mature width at the base would be six feet or wider, plant several shrubs instead of just the one. For a mound six feet at the base, plant a trio of 'Gretchen' in a triangle whose sides are all three feet. For larger mounds, plant a quartet of 'Gretchen' at the corners of a four-foot square. Remember: You'll need to be able to reach to the very top of the mound, which will also be at its very center. Mounds whose base is wider than six feet will require pruning by an especially long-armed gardener—or one who is comfortable using power hedge pruners while also bending at the waist.

 

To create an obelisk or a cone, let the young shrub grow for three or four years, so that a few major branches become evident. Late the following Winter, select the most central of them—whether or not it is also the tallest—and prune the others at the base. Stake the remaining branch to vertical, while also reducing any of its side branches by a third. Allow all stems to grow freely until the first frost of Fall. Then adjust the staking so that the central vertical—the trunk, as it were—is still securely but not tightly tied to the stake, and its new top extension is gently but firmly tied to the stake. Clip other new growth back by a third, also cutting back any growth—new or older—that now seems beyond the boundary of the desired full-size shape.

 

As 'Gretchen' assumes any of these mature sizes and silhouettes, you'll need to prune off more and more of the new growth each year, lest the overall size slowly increase. Even so, such "size creep" is almost inevitable. Every five years or so, prune more severely to re-establish the original dimensions by cutting off all new growth as well as some of the older growth beneath it. Unless you're comfortable with the skeletonized results through the Winter, do this "recapture the shape" pruning in early Spring. Then you'll need to wait just a week (or three) for emergence of the new growth that will begin to reclothe your form.

 

No matter how thorough your Spring pruning will be, over the Summer all clipped bushes of 'Gretchen' will produce plenty of new growth. It will be colorful, but as Summer progress, the shape will become shaggier and less distinct. If you want, you can recapture the intended shape with a second pruning in early Fall. A good rule of thumb is to delay this second pruning until after the first frost, so as to avoid encouraging soft and Winter-tender new growth.

 

If your bush is well-shaped already, this Fall pruning will be just a matter of cutting back new growth by two thirds (or, at the most severe, into the tips of the prior year's growth) to re-establish the sharp shape. If your bush is still in training, or has been allowed to outgrow its desired shape and size for several years, don't hesitate to view Fall pruning as the opportunity for major guidance or even wholesale renovations. Yes, if you prune older limbs back by half, you'll expose thick bare stumps. On the other hand, that very pruning could be just what's needed so that out-of-bounds branches are saved from snow or ice damage. A holly bush that is radically pruned in Fall shows all Winter that you have guts as well as strong ideas about the new shape it will begin to assume in Spring. 

Quirks and special cases

It's not realistic to maintain a well-pruned holly that also bears a satisfyingly heavy crop of berries each year. Some hollies—such as Ilex opaca, Ilex 'Nellie R. Stevens', and the meserve hybrids, including 'Gretchen'—bear flowers only on stems formed in prior seasons; first-season growth is foliage and stems only. Pruning that removes only that first-year growth, then, doesn't immediately affect the production of flowers and, more to the point in terms of showiness, the berries that follow. Indeed, such light clipping can improve the berry display, because the non-bearing first-year growth at the tips of the stems can be profuse enough to partially obscure the berries. Stems older than two or three years, however, no longer flower or berry, so if most or all first-year growth is removed annually, most remaining growth will become too old, and berry production will suffer.

 

If your goal is a well-clipped specimen year after year, accept that it will display few berries. Or plant another individual where you can allow it to grow free-range. If, however, you would be OK about allowing your shrub to display a good crop of berries one year and a more closely-worked shape the next, then follow the two-year pruning cycle recommended for 'Nellie R. Stevens'.

 

Although some hollies—Ilex crenata and glabra among them—form flowers on new growth, that still doesn't simplify things: Pruning is inherently concerned with removing new growth. And because the display of holly berries can extend well into Winter, there isn't much of a work-around by delaying pruning until early Spring: Growth that forms as a result of pruning as opposed to natural emergence from unpruned older growth is less likely to flower. In helpful coincidence, the berries of Ilex crenata and glabra are black, so are not usually considered as being showy anyway. So go ahead: Prune black-berried hollies to maximize their year-round shapeliness.

 

Are there hollies that flower on new growth and whose berries are showy? In such a large and diverse genus, no doubt. 

Downsides

All the blue hollies lack sufficiently stiff, sharp, and numerous thorns to deter deer. Without protection, they can be defoliated entirely by Spring. If you garden where deer are a problem, consider installing deer fence. At least put inexpensive "orchard" mesh around the bush each Fall.

Variants

In general, hollies are happy to hybridize, and just as happy to sport. With several hundred species in the genus and many more hundreds of named forms derived from them—over a thousand just of Ilex opacait's not unusual for even a compact garden to feature a half-dozen different hollies without any fear of repetition.

 

The "blues" are the original meserve hollies, including Ilex x meserveae 'Blue Girl' and 'Blue Boy, 'Blue Prince' and 'Blue Princess', 'Blue Stallion', and 'Blue Maid'. There aren't enough differences among these to merit a collection. Instead, you'd want to grow "the best of the blues," and leave it at that. The Prince/Princess pair is generally thought of as the hardiest, with the Princess the female that bears the heaviest crop of berries. The male blues are typically several feet narrower than the females at maturity, enough so that you'd notice their difference by their comparatively erect profile, not just their lack of berries. Blue hollies are well recommended for hedges. Remember that holly hedges bear relatively few berries: They are borne on the second- and third-year stems, portions of which are often clipped off during pruning. Using blue hollies as a hedge, then, is at cross purposes with the usual goal of including both sexes in any mass planting. The female hollies will bear few berries, and their broader branching habit will stick out, literally, in comparison to that of the males. Even if you have the space for free-range growth, and so can enjoy a heavily-berried hedge, inclusion of both sexes will make the hedge irregular. Plus, there will be the odd stretches of berry-free growth: The males. Instead, restrict mass plantings of holly to just one sex. For hedges, I recommend males. Be sure to have some free-range females elsewhere in the garden, so that the males' pollinating prowess isn't wasted. The pruning will diminish any individual male shrub's pollen production but, collectively, a hedge of males should have sufficient potency. For unpruned use, choose females, with a lone pollinating male lurking out of sight but still within a hundred feet. 

 

'Gretchen' isn't the only "blue" holly with foliage that's not literally blue. The leaves of 'Honey Maid' are green and yellow; this cultivar is reported as being frustratingly prone to reverting: New growth can be entirely green. The leaves of 'Casanova' are strongly edged in creamy white; that border is suffused with pink in cooler weather. It is less hardy than a typical blue: only to the warmer edge of Zone 6. 

 

The foliage of Ilex x meserveae 'Golden Girl' is similar to that of 'Blue Girl', but her berries are yellow-orange, not red. 'Little Rascal' is a male with a distinctive mounding and branching-from-the-base habit and, for a blue holly, at least, true dwarf stature: It matures at about two feet, with a spread of four. It is similar in appearance to 'Rock Garden', but is not nearly as dwarf or rigid. On the other hand, it's much hardier.

Availability

On-line and, rarely, at "destination" nurseries.

Propagation

By cuttings.

Native habitat

The meserve hollies were first originated by their namesake, Kathleen Meserve, in the early 1950s in St. James, a town on Long Island, New York. They have been propagated into the millions, and are planted nationwide.

 

The meserves are hybrids of Ilex rugosa, native to Japan and hardy in Zones 3 to 6, and Ilex aquifolium, native to England, and hardy only from the balmier, cooler-Summered, and well-protected portions of Zone 6 (chiefly Long Island and Cape Cod), to the mild-Wintered but never-sweltering Zone 9 climates found in North America only in coastal California and the Pacific Northwest. The pairing of such strongly contrasting species was an unlikely but sensationally productive match, resulting in shrubs with high-quality glossy foliage, thanks to Ilex aquifolium, and greatly enhanced hardiness (usually to Zone 5), thanks to Ilex rugosa. For the first time, hollies with lustrous leaves and heavy berry crops could thrive from Illinois to Vermont, not just the few "fantasy" locales—never too cold, never too hot—such as Martha's Vineyard or the Hamptons. See "Variants," above.

 

'Gretchen' is a sport of 'Blue Princess'.

 
 
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