Mast Young Plants window box trial

Novelty Window Box Planters By Vaughn Fletcher

These unique and innovative combinations incorporated creative design, interesting textures and intense colors.

I have been attending the Mast Young Plants annual trial in Michigan for over 15 years and have incorporated many of their new varieties in my trial articles. This is an extensive trial incorporating trials beds, hanging baskets, deco pots, saddle planters and window planters. I want to highlight and focus on window planters that have been a part of the trial since its inception.

This is the most extensive window box trial I have seen in all my years of trial evaluations. The components of these planters include genera and varieties from multiple breeding companies, and Mast offers many of them in their liner program. This gives the Mast team team the opportunity to display and trial many diverse accent plants in their creative designs, incorporating and combining multiple components.

The use of window boxes or planters may have begun with the Romans, but throughout history we see the utilization of window boxes for growing herbs, food, medicinals and ornamental plants. In the current marketplace, we see many different styles of window or porch planters including wire frames, terra cotta, wood, wrought iron and many different colors. They offer practicality and functionality in many urban settings where space is limited, and provide consumers with utility and aesthetics. The window planters in the Mast trial are mostly 36 inches long and were planted as liners directly into the garden week 24. The soil mix is Berger BM6, and the planters were fed twice a day during July and August with 17-5-17.

I am highlighting planters that comprised assorted components and demonstrated the attributes of texture, color, form and uniqueness when I visited in mid-August. There may be plants that I list that are not visible in the planter, and that is because they did not have the vigor to compete with the other components later in the summer. I hope you will find inspiration from these planters and glean design ideas for the spring season. Since these planters were created by the Mast team and incorporate assorted varieties from many breeders, they are listed only by number, and that’s how I will refer to them.

Components: Coleus ‘Campfire’, coleus ‘Great Falls Niagara’, alternanthera ‘Little Ruby’ and Muehlenbeckia axillaris Creeping Wire Vine

This design manifests the upright habit and striking coppery orange leaf color of coleus ‘Campfire’ from Ball Floraplant. This upright variety is complemented by the trailing coleus ‘Great Falls Niagara’ from Dümmen Orange, which exhibits bright bicolor leaves and is an outstanding filler for partial shade or full sun with excellent color stability. Alternanthera ‘Little Ruby’ is one of the best low-maintenance warm-season accent plants, with foliage shades of purple and burgundy. It is adaptable in containers, baskets and landscape beds. The Creeping Wire Vine is a ubiquitous component in mixed containers and baskets with its vining habit, lustrous small leaves and season long durability.

Components: Strobilanthus Persian Shield, artemisia ‘FanciFillers Sea Salt’, setcreasea Purple and tradescantia ‘Purple-Silver’

The colorful foliage components of strobilanthus, setcreasea and tradescantia have been in the market for many years. They offer vibrant purple shades and are adaptable as fillers and spillers. The artemisia is part of the Westhoff FanciFillers collection of accent plants with varied textures, leaf colors and trailing habits. Sea Salt demonstrates the power of gray as an accent component in mixed planters.

Components: Artemisia ‘FanciFillers Sea Salt’, impatiens ‘Double Silhouette’, setcreasea ‘Purple’ and coleus ‘Marrakesh’

The impatiens lacked the vigor to compete and disappeared in this combination, but the other components flourished, especially coleus ‘Marrakesh’, which is part of the Terra Nova Coleus Collection and has been in the Mast coleus program since its introduction. This is one of my favorite coleus varieties for many reasons, including the unusual foliage shape, striking multicolored foliage, mounded habit and exceptional garden performance from Florida to Michigan. It is recommended for partial shade, but I have seen it used in a sun exposure in northern regions. Incorporating the artemisia adds a unique color combination with the multicolored coleus and purple setcreasea.

Components: Rudbeckia ‘Rising Sun Chestnut Gold’, euphorbia ‘Star Dust Super Flash’, artemisia ‘FanciFillers Sea Salt’ and torenia ‘Moon White’

This versatile rudbeckia provides a canopy of color. I have highlighted the attributes and beauty of ‘Rising Sun Chestnut Gold’ in a previous article. This variety has received countless trial awards the past two years for its prolific flowering, excellent branching, compact habit and day length neutrality. It is new to the Mast liner program for 2021 and was chosen as a top 10 favorite by trial visitors this summer. It deserves consideration in summer and fall programs. ‘Star Dust Super Flash’ from Dümmen Orange is one of the most popular euphorbia varieties for spring programs with a compact, uniform habit. The vegetative torenia Moon series from Danziger is compact, available in six colors and excellent in mixed containers.

Components: Phlox ‘Gisele Red, ajuga ‘Feathered Friend Noble Nightingale’, lamium ‘Pink Pewter’, begonia ‘Elatior Clara’ and setcreasea ‘Purple Variegated’

In this combination, the standouts are the vigorous filler lamium ‘Pink Pewter’ and the vibrant and saturated red flowers of phlox ‘Gisele Red’. I highlighted the summer performance of this versatile phlox series from Selecta One in previous articles, and it is a significant component in many of the window planters. There are now eight colors in the series including the vibrant Red, which is outstanding in containers and landscape beds. The setcreasea accents the other components and adds verticality to the planter, giving it a more dominant presence.

Components: Geranium ‘Patriot Salmon’, petunia ‘Surfinia Dark Red’, verbena ‘Lanai Magenta’, calibrachoa ‘Cabrio Eclipse Strawberry’ and phlox ‘Gisele Red’

This is a colorful, well-balanced and sun-tolerant combination planter. The geranium Patriot series, introduced many years ago, continues to perform and is a uniform, vigorous, and well-timed series of 11 varieties with excellent garden performance. Petunia ‘Surfinia Deep Red’, introduced over 20 years ago, continues to be one of the best dark red petunias in the market. Calibrachoa ‘Cabrio Eclipse Strawberry’ was introduced last year and was one of the top calibrachoa performers in 2019 trials.

Components: Artemesia ‘FanciFillers Sea Salt’, salvia ‘Saucy Red’, petunia ‘Splash Dance Magenta Mambo’ and calibrachoa ‘Chameleon Blueberry Scone’

I want to focus on salvia ‘Saucy Red’ because of the value it brings to the garden. This is a splendens species available in three colors: Red, Coral and Wine. The series is sterile, vigorous, self-cleaning, and one of the most floriferous salvias in the market. Production application includes quarts, gallons, mixed containers and landscape beds. The plants mature at 2 to 3 feet, and Mast offers Red and Coral in their liner program. It is also in the Southern Living Plant Collection. Obviously ‘Saucy Red’ has overwhelmed the window box but it does demonstrate its impressive flower power. We are all familiar with the calibrachoa Chameleons, and their multicolor and transitional flowers provide a color palette unlike any other calibrachoa series. The ‘Splash Dance Magenta Mambo’ is a new speckled variety from Danziger for 2021. This series comprises three selections including Bolero Blue and Purple Polka, which I highlighted in my Costa Trial article in early summer.

Components: Osteospermum ‘Daisy Falls White Amethyst’, nemesia ‘Sunglow Yellow Bicolor’, setcreasea ‘Purple’ and petunia ‘Itsy Magenta’

As you would expect in mid-August, the osteospermum and nemesia were devoid of many flowers, but this window box was dominated by the petunia ‘Itsy Magenta’, which was exclusive to Mast Young Plants in 2020, but is open to the industry for 2021 and available from many different suppliers. I wrote about the beauty of this variety in my September 2020 article on my container garden, and it was in every trial that I visited this summer. It was displayed and trialed in mixed containers, mono containers, baskets and landscape beds. It was a top performer in multiple trials. I used it as a filler and spiller, and it was a carpet of color. In every trial it was consistent in growth habit, floriferousness, color vibrancy, color stability and heat tolerance. The vibrant magenta flowers are small but incredibly prolific with outstanding color coverage. The setcreasea is a multipurpose plant used as a ground cover in the Deep South, an indoor foliage plant, and an excellent accent filler and spiller in mixed containers and baskets. It offers durability and heat and humidity tolerance.

Components: Petunia ‘Big Deal Flamenco Dancer’, geranium ‘Calliope Medium Violet’, cuphea ‘Mexicana’ and phlox ‘Gisele Red’

This was one of the most colorful planters in the trial, and it demonstrated the vigor and heat tolerance of all the components. I have described the durability and toughness of the ‘Giselle Red’ earlier in this article, and it manifested the floriferousness that we have come to expect with this variety. Geranium ‘Calliope Medium Violet’ needs no introduction. This interspecific series and top garden performer is an integral part of geranium programs throughout the country. Cuphea ‘Mexicana’ is one of the most heat-tolerant varieties in the market and is outstanding in mixed containers with an abundance of small violet flowers. Petunia ‘Big Deal Flamenco Dancer’ exhibited heat tolerance, vigor, and floriferousness with grandiflora size flowers. The white petals with bright purple stars were eye catching. This series consists of six varieties with grandiflora size bicolor flowers, and consumer application includes baskets and landscape beds.

Components: Argyranthemum ‘Sunny Spring’, geranium ‘Patriot Salmon’, petunia ‘Itsy Magenta’ and senecio ‘Angel Wings’

I described the attributes of the Patriot series and ‘Itsy Magenta’ earlier in this article. Argyranthemum ‘Sunny Spring’ was introduced in 2020 and is one of eight varieties in the Danziger Angelica Collection. This variety was impressive in the trial with an abundance of bright yellow, anemone-shaped flowers positioned above the foliage canopy. It is available in the Mast Young Plants liner program for 2021. The plant that created the most interest for me was senecio ‘Angel Wings’. This is a new addition to the Mast liner program for 2021, and with this intense and stunning gray color will become an excellent accent plant for sun combinations, mono planters and beds. The velvety, silky silver leaves are unusual, bold and distinctive, and they add texture, color and form. This is a new addition to the Mast liner program for 2021.

Components: Artemesia ‘FanciFillers Sea Salt’, phlox ‘Gisele Red’, brachyscome ‘Fresco Candy’ and lantana ‘Santana Red Orange’

This planter is dominated by the phlox and the artemesia. ‘Gisele Red’ is ubiquitous in many of the planters — and for good reason. It is a prolific flowering phlox and manifests deeply saturated red florets. Additional attributes include exceptional heat tolerance and tight internodes. This series has been successful in mixed containers since its introduction and is now augmented by this outstanding Red variety for 2021. The silvery gray artemesia ‘Sea Salt’, with its unique leaf structure, growth pattern and stable gray color, would generally dominate a mixed container with its vigor, but it accentuates the phlox, creating an eye-catching arrangement. Lantana ‘Santana Red Orange’ (and Gold) comprise the most vigorous series in the Danziger lantana portfolio.

Components: Petunia ‘Itsy Magenta’, lysimachia ‘Variegated Lemon’, geranium ‘Patriot Salmon’ and bacopa ‘Calypso Jumbo White’

This is another example of the component petunia ‘Itsy Magenta’ dominating the container with a prolific flower canopy and a dense spreading habit. Lysimachia ‘Variegated Lemon’ is an excellent accent plant with a bright shade of green that works in sun or shade. It brings excitement and brightness to the combination without a heavy presence. The bacopa was flowering sparingly, competing with the other components. ‘Patriot Salmon’ was an essential thriller in many of the window boxes with multiple flowers above the canopy, which provided superlative color.

Vaughn Fletcher

Vaughn Fletcher is president of Fletcher Consulting. He has been in the horticulture industry since 1971, working in many areas including landscaping, garden center and greenhouse production, greenhouse and nursery sales and sales management. He can be reached at