Emerging Crops: Today’s Euphorbia: A New Breed By Rick Schoellhorn

Growers are always looking for the next breakthrough in crops, something that brings a new look, and a new price point, to their businesses. Once you have been in the industry long enough, you begin to see that certain breakthroughs are simply the recycling of crops that were once popular and then faded from the consumer's eye. Of course, some breakthroughs are just that — a true exploration of new crops. Recycling crops is easier because the information is already out there on how to grow these plants. Breaking new ground in crop diversity is a bit more complicated because there are a lot of unknowns, and let's face it, unknowns scare people; they wait to try the truly new plants until the kinks are worked out of production. Sadly, those who wait also miss the chance to make the higher price points that a truly new crop offers.

The discovery and marketing of new species in the genus euphorbia include a bit of both plant-introduction models: recycling the old and inventing the new. Basic production information for euphorbia is available in the form of poinsettia production guidelines, but the new species and hybrids making their way into the market are much simpler to produce than our traditional holiday crop. Better yet, they have a wider market season and should offer wholesalers and retailers a chance to make money on the crop rather than just maintaining cash flow. So, as we look at some of the promising new euphorbs (slang for euphorbia) remember the basics are the same, the uses and markets are a lot less limited.

Varieties To Watch

The family euphorbiaceae is a huge family and awesomely diverse; there is so much out there to work with, and we are seeing just the tip of the iceberg on the market so far. The family is tough, with great performance under hot and dry conditions, and some species do quite well under cooler conditions. Experiment with what you can find, and you'll see the potential for market expansion.

Euphorbia amygdaloides (and its hybrids) also are growing in popularity, despite their name. They are easy crops for the grower and homeowner to succeed with. The highlight here is the foliage and texture of the plant. Depending on the hybrid, leaves may be gray, deep purple, or tricolor white, green and pink.

Cooler production temperatures enhance foliage color and high temperatures reduce the impact of the foliage tone. This group is quite cold tolerant and usually rosettes from fall to winter, emerging in spring with luxurious foliage followed in late summer by distinctive "flowers" that are actually cup-shaped bracts with rather insignificant cyathea (true flowers). All in all, the flowering is spectacular for texture and adds a bit of otherworldly sci-fi to any garden.

My personal favorite is Euphorbia cotinifolia (cotinifolia refers to the plant's resemblance to Cotinus sp. or smoke bush). This plant is still a bit of a rarity on the market but really amazing for use in hot, dry climates where the burgundy foliage intensifies with heat rather than fades as it does with so many woody crops. It is not frost hardy but has excellent growth ç and performance in hot, humid and hot, dry locations. Inner foliage may turn bronze to gold as the plant grows, giving a luminescent quality you won't find elsewhere.

Euphorbia fulgens, the plume euphorbia, is an old standard in the cut flower industry and is now rarely seen in the United States. The arching stems literally are covered with small, intense, red, orange, yellow or white blooms. This plant deserves some more attention and would be a great drought-hardy addition to mixed containers.

Don't forget crown of thorns (E. milii ) and giant crown of thorns (Euphorbia x lomi); both are outstanding architecturally and for flower color. Slow, they are easily grown and spectacular when in flower. Best flowering is under short-day conditions, but they often continue well into summer with bicolor, salmon, red, pink and yellow bracts.

Pushing The Definition

Of all the great new euphorbia on the market, two really stand out as completely different from anything else currently available.

'Diamond Frost'. The release of euphorbia 'Diamond Frost' (Euphorbia hypericifolia, recently reclassified as Chamaesyce hypericifolia) from Proven Winners opens a new market on the use of euphorbia as a bedding plant. This hybrid is ever-blooming and requires no photoperiodic manipulation. In form and texture, it resembles baby's breath (gypsophila) and works equally well in mixed containers or monoculture 4-inch pots or hanging baskets. As with all euphorbia, it is drought and heat tolerant, but it also is tolerant of cool early season conditions. For best performance, 'Diamond Frost' requires high light levels, so it should be kept in the warmer, brighter portions of the greenhouse. Gauging by the responses from trial gardens around the United States, 'Diamond Frost' has a continental appeal and uniformly strong performance from Canada to the Southern U.S.

To date 'Diamond Frost' is the only euphorbia of its type on the market in the United States. In Europe, the genus has a longer history, and though this crop does not offer a lot of color variation, a pink form is floating out there somewhere as a diamond in the rough; perhaps in the future we'll see more from this genus.

'Dulce Rosa'. Part of the Ball Centennial collection, this intergeneric hybrid with poinsettia is barely recognizable as the standard holiday plant. It has long, thin bracts of shocking pink and a very un-poinsettia-like presentation. This kind of breeding innovation (Ecke Ranch) could possibly be the bridge many of us have been looking for that will expand the poinsettia into spring markets. 'Dulce Rosa' is a beautiful addition to spring offerings but easily lost in holiday poinsettia production. The plant will make a big impact in Mother's Day and Easter sales, if we can convince growers to be brave and produce it at those times.

'Dulce Rosa' is photoperiodic, forming bracts under short day conditions, which makes it a great early season crop. It looks weird as a poinsettia but great as a bedding plant grouped together in masses. It is sure to make a unique statement in spring sales, very popular in consumer trials and definitely worth trying.

Culture Tips

With the exception of day length, culture is similar for most euphorbias. Specific culture follows, but the main items to watch are light and watering. If you give plants bright light and low water, you shouldn't have any problems.

Light: High light is a requirement. These are usually desert-type plants, so the brighter the light the better

Temperature: Give warm production temperatures and avoid chilling except where noted in text. Typical guidelines are 65¼ F nights and 75-80¼ F days.

Watering: In all cases, the quickest way to kill this crop is to overwater, especially under cool conditions. Always use low moisture levels and allow to dry between waterings.

Fertility: Like poinsettias, a higher fertility range of balanced fertilizer will work best. A good starting point is moderate to high fertility levels.

Humidity: Remember, these are typically desert plants; they like moderate to low humidity levels.

Soil: Always use a well-drained media to prevent overwatering and make sure there is plenty of air around the roots.

Pests and problems: Most varieties do not have lots of pest problems. The most common are root rots from overwatering, aphids and mealybugs.

Growth regulators: In most cases, no growth regulators are required.

Uses: Since there is such a wide range of plant material, euphorbias can be used in most container formats: mixed containers, 4- and 6-inch containers, and hanging baskets.

Rick Schoellhorn is the director of new products for Proven Winners LLC; he can be reached at rick@provenwinners.com.

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