January 2015

Coleus: Foundation in Foliage By Terry Howe

In today’s gardens, drama doesn’t have to come from a showy bloom. The modern gardener is appreciating foliage plants more and more. The appeal goes beyond just color – there’s texture, shape and versatility, too. Gardeners are exploring gardening as décor, and they’re selecting plants with fashion-forward traits. One particular crop that meets all these needs is coleus (Solenostemon scutellarioides). In the garden it’s durable, with a wide range of garden-use potential (from landscape to containers). On the bench, coleus grows quickly with few production complexities. The National Garden Bureau has tagged 2015 as “Year of the Coleus.” This article will take a closer look at how growers can benefit from the latest breeding efforts, and how they can ultimately sell these qualities to the consumer.

Breeding & Selection

Since its revitalization in the 1980s, coleus has evolved to become a premium plant option. One of the singular breakouts was the Kong series back in 2005. The appearance of the ultra large leaf size really evoked a second look at a plant that was typically seen as a workhorse for filling bed space. With Kong, now there was a reason to have coleus as a focal point. Followed up by the surge in the quart-sized container segment, the continued healthy rise of mixed container sales, and the demand for unique plants that can multi-task, the coleus on the market in 2014 are a far cry from the coleus of 10 years ago.

There are a remarkable number of recent introductions for both seed and vegetatively propagated coleus. Breeding companies continue to strive for varieties with more sun tolerance, delayed (or non-existent) flowering, better branching and compact habit, as well as trailing forms. Sun performance is a primary concern for the breeding teams at PanAmerican Seed. The more versatile we can make the product in outdoor performance, the more worry-free it is for the landscaper or home gardener. The key is to make coleus easy and carefree. It is this, plus the quick establishment after planting, that has made coleus lately indispensable.

Vegetative coleus with late- or non-flowering performance provide vigor in the landscape that many consumers are looking for. Varieties like Ball FloraPlant’s ‘Wasabi’ or ‘Henna’ tolerate sun conditions well, and can grow to bush-like sizes. In general, coleus assortments that can take either sun or shade have increased longevity in the garden, along with a broad range of unique colors. This gives gardens and containers a focal point that is not only beautiful but durable, too.

Today’s coleus are also selected for exceptional tolerance to a wide range of environmental conditions and disease pressures, especially looking for tolerance of downy mildew. Its resilient nature is what keeps coleus at the top of the list for shade alternative plants as a replacement for Impatiens walleriana.

Plus its foliage shape is very ornamental, and the leaf texture should be a consideration when planting coleus in mixed combinations. The new Marquee coleus collection from Burpee Home Gardens has a lancelate leaf shape, while the deeply dissected and coral form leaves of the Under the Sea collection from Hort Couture keep things interesting for the gardener seeking the unique. Trailing types like Lava Rose offer a smaller leaf size and a complementary habit for containers and vertical gardens.

But let’s not undersell coleus’ broad color range. Selections can feature solid color or an alternate hue on the leaf underside. It could also exhibit blotches, splashes, veining, flecks and margins. For color options, PanAmerican Seed’s focus is to put our most unique colors into our Sun Premium assortment. The best leaf coloration is achieved with exposure to morning sun and some degree of afternoon shade. Lime Delight, a striking chartreuse, mixes with any color in the garden and continues to be a great focal point with eye-popping color. The “chocolate” types like ‘Chocolate Mint’, ‘Chocolate Covered Cherry’, ‘Chocolate Splash’ and ‘Mighty Mosaic’ were introduced to extend coleus beyond your more basic solid color offerings. Their habits vary widely, from petite to majestic, which was the breeder’s intent.

More Coleus Tips

The best thing about coleus is that it is easy to produce. Culture for growing vegetative coleus is pretty straightforward. Some things to remember on the bench:

• • Coleus are low to moderate feeders. Excessive fertilizer can dull the color.
• • Vegetative coleus benefit from an early pinch (two to three weeks after transplant).
• For shade coleus, and some special tips for large-leafed Kong:
• • Don’t pinch Kong. The leaf size will be much diminished on new growth.
• • Spacing encourages best branching for full, lush plants.
• • Watch out for too much sun exposure. This will reduce the leaf size.

The best recommendation for garden retailers who want to sell more foliage plants is to add coleus to ready-made mixed containers – from smaller decorative pots to large showpieces. Sell in quarts or gallons, and encourage planting of coleus and other foliage plants as thrillers in garden beds or combos. Definitely use signage to indicate to the customer if a particular coleus can take sun and shade. Finally, one forgotten retail category is that coleus makes a fantastic indoor lifestyle plant. Why not have a pop of textural color in your home or office?