Color is king

The only thing consistent is change. In the plant business, we may not notice immediately, but plant trends, customer preferences, propagation, and production practices are continually metamorphosing. In recent years, the ascent of brands, savvy marketing, and a plethora of new and arguably improved trees and shrubs, has elevated our industry.

Color is the common denominator that has dictated the commercial relevance of most new introductions. There will always be places and needs for green, such as Buxus, Taxus, Juniperus, Ilex, Rhaphiolepis, et al., however, color is king.

Breeders like Buddy Lee have elevated the staid azalea market by introgressing reblooming genes into the current crop of 30 cultivars constituting the Encore azaleas from PDSI.

Bill Radler bred the highly disease resistnat Knock Out roses that paint American landscapes in pink and red (other colors, too), singles and doubles. And in the Dirr garden in Athens, Ga., they flower from April to November. With thousands of competing rose cultivars, a Wisconsin amateur breeder raised the bar to a level never before achieved. Bill’s foray into rose breeding is well documented online. Knock Out roses are the largest selling roses in the world, and the success has allowed Bill to establish a philanthropic foundation. Our industry and gardens are better for Bill’s ingenuity and kindness.

Lilac proven winners color choice; Sorbaria Dirr

The University of Georgia, Plant Introductions Inc., and Bailey Nurseries introduced remontancy (reblooming) into Hydrangea macrophylla with the development of Endless Summer The Original, ‘Blushing Bride,’ Twist-n-Shout, and the newest, BloomStruck. Over 23 million of these four selections have been sold since 2004. This cadre offered floral success where in the past there was only hope, at best. Remontancy is now the prime ingredient in new H. macrophylla cultivars.

Those plants generated consumer enthusiasm and made money for everyone in the supply chain, from the breeder to the retailer. I visited Gerten’s Garden Center in St. Paul, Minn., in late September 2015 and noticed a #5 viburnum ‘Emerald Triumph’ priced at $29.95, while H. macrophylla BloomStruck in a #5 commanded $49.95. Production time for the viburnum was at least another year. Certainly, the profit margin is significantly greater for Bloomstruck.

Robert King, the former plant buyer for Pike Nurseries in Atlanta, had the best line when I asked (20 years ago) about the proliferation of new introductions. He said nobody comes to Pike’s and asks, “what’s old?”

Landscape, Dirr

So the journey continues to breed flowering shrubs that compliment and/or supersede the azalea, rose, and hydrangea described above. For example, Encore azaleas were the first, and subsequent competition includes Always Azaleas, Bloom N’ Again, Evermore, Bloom-A-Thon, ReBLOOM, and Déjà Bloom. We are all better for the competition. May the best plants grace our nurseries and consumers’ gardens.

In early February 2016 I presented the “New Flowering and Colorful Foliage Shrubs and Trees: Gardeners Love Color” lecture in Chicago. All 600 seats were taken with some attendees standing. There continues to be passionate enthusiasm for new plants. Below are a few examples I presented in Chicago.

Carolina sweetshrub

For as long as I can remember (I just turned 72), I have loved Calycanthus floridus, the Carolina sweetshrub. Then ‘Hartlage Wine,’ ‘Aphrodite,’ and ‘Venus’ arrived, hybrids of C. floridus and C. chinensis. I have grown them all, with ‘Hartlage Wine’ and ‘Aphrodite’ producing large red-maroon flowers starting in April in my garden and sporadically into late summer. ‘Aphrodite’ is listed as fragrant, but my olfactory senses perceive nothing. The potential game changer in the Calycanthus group is ‘Burgundy Spice’ (C. floridus) with shiny deep chocolate-purple foliage. Rich Hesselein, of Pleasant Run Nursery in Allentown, N.J., developed this wonderful plant. Star Roses and Plants will introduce the plant to commerce.

Flowering quince

Tom Ranney, breeder and horticulture professor at North Carolina State University, has taken the rag-tag, rumpled, cat-and-rubbish-eating, spiny-stemmed Chaenomeles speciosa and bred three thornless, almost fruitless (I observed fruit on scarlet), spectacular double-flowered, pink, orange, and scarlet selections. The Storm cultivars (Double Take series) have proven reliable performers with flowers running the length of the stems. Each flower resembles a rose bud, opening to about 2½ inches in diameter, and long lasting because of the cool weather in March and April in Athens. Expect size in the 4-5 feet range.

American filbert

Seldom does anyone fantasize about Corylus americana, but for naturalizing, wildlife sustenance, and reasonable fall color, plus adaptability from Canada to Florida, there is merit. Bailey Nurseries has a purple leaf, seed-produced selection that has performed nobly in Minnesota and Georgia. Thomas Molnar of Rutgers University has purple leaf hybrids using C. americana that are resistant to eastern filbert blight (EFB). Based on my discussions with Tom, there are other great Corylus on the horizon including weeping, contorted, with cut leaf, purple summer foliage, husk (involucre) color, edible nuts, and orange-red fall color, in many combinations, all with EFB resistance. This is an example of integrating color into a native and establishing a pedigree for everyday consumer acceptability.

Lilac

Quince, Proven Winners

The reblooming trait has elevated Syringa to retail prominence with the advent of the Bloomerang series. One might question (at least I do) the potency of rebloom, but the plants do push forth smaller fragrant flowers in summer through fall. From Maine to Georgia, I have observed the original and Bloomerang Dark Purple. The plants have captured the retail market as evidenced by their ubiquity in commerce. Again, remontancy (reblooming) coupled with excellent marketing are driving the sales. At Plant Introductions Inc. we assembled a collection of 50 lilacs considered heat tolerant. Reblooming was to be introgressed into our heat tolerant lilacs. And seven years later, we are still at the work bench.

Viburnum

From my University of Georgia days to the present, I attempted viburnum breeding. Most nursery visitors showed minimal or no interest, however, Pearlific (from UGA), Spring Lace (also from UGA), and Opening Day (PII breeding) are now in commerce. It is humbling when one has to beg, plead, and cajole nursery visitors to at least test the plant. Pearlific is compact, maturing to 6 feet, with lustrous dark-green evergreen foliage, fragrant white flowers, and red to black fruit. It is licensed to McCorkle Nursery in the Gardener’s Confidence collection. Spring Lace, a sister seedling to Pearllific, is evergreen to semi-evergreen, with larger, shiny, leathery, dark green foliage; fragrant, white lacecap flowers; and, to date, no fruit on the 10-year-old parent plant. The flowers are reminiscent of the lacecap ‘White Wave’ Hydrangea macrophylla. Both have been extremely heat, drought tolerant and are Zones 6-9 adaptable. Bailey Nursery introduced Spring Lace in 2016.

I received an email from Kevin Spellman with photos of a bird-planted, V. plicatum f. plicatum, with an upright habit and snowball-shaped flowers. I requested and received cuttings and a few fruits in 2009-2010. The original plant was shared with Gary Ladman of Classic Viburnums in Upland, Neb. He named it ‘Spellbound,’ and in flower and foliage it has that mystic quality.

Three seedlings were grown from ‘Spellbound’ resulting in two snowballs and one lacecap. PII’s Spellbound-01-11 was compact and developed pretty, red-purple-maroon fall color. Like ‘Spellbound,’ the dark green, pleated foliage is heat and drought resistant. Bailey Nursery decided to introduce the plant under the name Opening Day. Side-by-side in the Dirr garden, Opening Day is two-thirds the size of ‘Spellbound,’ estimating 5-8 feet high and almost as wide. Most impressively, the first wave of cuttings from Griffith Propagation Nursery is sold out.

The above viburnums, happily ensconced in the Dirr garden, have exceeded expectations for performance. Bonnie and I love them all.

Bush honeysuckle

Diervilla species in their typical native garb never excite, however, breeders and selectors have been dressing them with color. The early Summer Stars and ‘Butterfly’ introductions moved the dial a degree, but Cool Splash with white-margined foliage, as well as Kodiak Orange, Kodiak Black, and Kodiak Red have piqued interest. In North Georgia, Diervilla sessilifolia is everywhere, yet goes unnoticed because of non-descript green leaves, small yellow flowers, brown capsular fruits, and brown winter stems. I collected seeds from diervilla in the wild that had bronze/copper in the foliage (capsules persist). Many seedlings later, there is nothing to compete with the above mentioned selections. Diervilla species are extremely adaptable plants growing in sun, shade, acid, rocky, gravelly habitats. On Georgia’s second highest mountain, Rabun Bald, it is common at 4,696 feet elevation. Like the proliferation of colorful weigela cultivars, I theorize diervilla will travel the same path. In fact, diervilla and weigela are related, and hybrids between them have been consummated.

Ural false spirea

To further build the case for color, let’s examine Sorbaria sorbifolia, Ural false spirea, with green leaves, white flowers, suckering habit and potential invasiveness. In Maine, I observed large Sorbaria colonies in the shade of native trees. Then along comes ‘Sem’ with coppery-orange new growth, dark green mature foliage, and slightly smaller stature. Actually, quite elegant for foliage color and a free-flowing habit. At PII, a seedling selection with red new leaves and red-purple fall color was bred. An old raggedy, unkempt species has become acceptable with the addition of color.

Chaste tree

Let’s wrap up this color therapy session with Vitex. Some 250 species are known with only V. agnus-castus, V. negundo, and to a lesser degree V. trifolia showing cold hardiness (with V. negundo the hardiest). Most V. agnus-castus cultivars are behemoths with the popular ‘Shoal Creek’ ascending 15 to 20 feet high. The beauty resides in the summer flowers, lavender-lilac to almost blue on new growth, beloved by bees and hummingbirds. Vitex has the magical DNA that fosters remontancy, so new growth will produce flowers into autumn. Even in Zones 5 and 6 it functions as a dieback shrub and still flowers. In the past, breeders showed little to no interest in manipulating the genes for new flower colors, foliage colors, and habit. However, I stumbled upon information from Texas, Louisiana, California, and Georgia, pointing to a modern day epiphany with the genus.

North Dakota State University

My son, Matt, called me about a compact V. agnus-castus with deep violet-blue flowers. He asked me to take a look, and I told him he might have discovered the Mother Lode for breeding. Indeed, seedling populations were dwarf, intermediate, and about the size of the original. The original became Delta Blues, 8-10 feet high and wide, dark blue-green foliage, dense habit, and the darkest blue-purple flowers. One seedling became Blue Puffball, 3 feet by 3 feet, with lighter blue-purple flowers. Growers are excited about both cultivars for the reasons enumerated.

At PII, dusty lavender-purple coloration was integrated into a vitex hybrid, but unfortunately only on the undersides of the leaves. Our hope is to flip the color to the upper surface. A hybrid with lavender-purple foliage and blue flowers would prove a major advancement. The foliage color does not fade in the heat of summer. This hybrid has never developed leaf spot under overhead water or garden culture. I trained it into a small tree and the colorful undersides are evident in the slightest breeze.

I am hopeful that it will be introduced in the future. And that’s what breeders do best – dream! On occasion, the dreams become reality and our gardens richer and more colorful.