Recipe for Beauty: An Introduction to Hippeastrum

As a child I remember the sweet smells of cake batter in the kitchen, and the occasional sneeze from too much cake flour in the air; my mother basting the Thanksgiving turkey and the aroma of delicious sweet potato pies baking in the oven. Now that was a recipe for good eating!

I remember my instructor as we worked together for the first time. “Today we will learn to make bread.” he said. Childhood memories of my mother’s cooking came to mind and I thought I must be in the right career field. Plants and eating, what a job! As we crafted medium for a bulb, it wasn’t the fresh baking of bread that would be filed away in my memory but this would be my first encounter with Hippeastrum. Who would have thought the same way one uses a recipe to create a superlative dish is the way I was introduced to Hippeastrum?

Upon being introduced to this bulb, I was overtaken with inquisitiveness to learn everything about this phenomenal plant. I discovered brilliant cultivars such as ‘Christmas Star’ and ‘Miracle’, learning that these bulbs were also wonderful additions to the Christmas assortment. My search led me to discover that most Hippeastrum cultivars were marketed as potted plants, mostly during the winter in the United States. I had discovered a new recipe and now it was time to gather the ingredients on how to maximize the potential for a wider market spectrum through alternative production methods such as cut flowers

Hippeastrum or Amaryllis?

For any grower entering into the world of Hippeastrum, the first thing that must be learned is the difference between Hippeastrum, and amaryllis. Although ‘amaryllis’ is the common and trade name for the species, Hippeastrum, is the genus name, and is used to botanically separate the two groups.

While great for pot production during special holidays, this plant can be further explored outside of its marketed window through field and cut flower production. For these, bulbs are planted in late January and grown for harvest in late March through early May. Hippeastrum, is native to subtropical and tropical environments, meaning it would be comfortable most of the year in zones 8 to 11. For cut flower production, however, it is best to limit production to zones 9 through 11, which includes Florida and parts of Texas.

While Florida’s subtropical humidity may seem attractive, it may not be the best environment for field production, which requires moist soil and warmth during the growing period, yet dryer and cooler conditions in dormancy. Some areas of the South such as coastal Texas may fit this description. With a growing season from March through December, hot summers and warm winters, and well-drained suitable soils, this region could lend itself for field production.

More Than Just a Pot Crop

Bulbs are grown mainly by specialized growers in the Netherlands, Israel, and Brazil. For pot production, compact cultivars are used. Cut flowers, however, need the exact opposite criterion. When growing any flower for production, long stems, and plants with high floral output is highly desired.

Selecting the Right Supplier

Before ordering, consider bulb grade, cultivar habit, and flower type. Bulbs may be grouped by  single-, double-, and specialty-flowered varieties. Select a supplier who carries cut flower cultivars, and not only pot varieties. It is also important to research which cultivars will give you high market return. Selecting a cultivar that is inexpensive to purchase but has a low market return will result in low profit margins and high expense outputs.

Preparing your Hippeastrum

Growing my first Hippeastrum bulb crop for a display at Longwood Gardens was like working with a recipe for the first time. Light, temperature, and water volumes were something that had to constantly be monitored. Too much of either could tip the scale and throw off the “recipe”.

They generally need 6 to 8 hours of direct sunlight, and prefer well-drained, moist, and loamy to nearly sandy soil. The medium should be low in organic matter, meaning no compost or pine bark-based amendments.

Light is key, and its consistency is important. Increasing the light duration during blooming phases will increase the bulbs’ transpiration and put more energy into flower production. Maintaining a consistent, high light environment will reward you with bold colors. Be sure no structures or other plants cast shade on your crop.

Temperatures are not as critical, but it is good to monitor soil temperatures in winter, as bulbs are highly susceptible to frost damage. In summer, ambient air temperatures should be monitored as high temperatures can cause scapes and buds to burn. Hoophouses and shade structures are simple solutions to maintaining your field crop.

The main concern for water is around the roots. The soil needs to stay well drained, as pooling water around the bulb and roots can lead to bacterial and fungal disease. Avoid overhead watering late in the day to minimize moisture and prevent fungal buildup. Keeping these environmental factors in order will allow you to prepare a field prime for producing optimal plant growth and flower development.

Balanced and timely fertilization is important. A moderate to low amount of fertilizer is preferred over intermittent highly concentrated applications. Fertilization occurs during the active growing season, as soon as foliage develops, until foliage starts yellowing with the onset of summer dormancy.
Slow-release fertilizers can be applied to the field and slowly release into the soil over the course of the growing season.

Fertigation may be the preferable option if a soaker hose system is installed.

In the post season, it is important to go through the field and remove any yellowed foliage to control disease pressure for the next cycle.  During this dormant time, the field should be scouted for any bulbs that are producing adequate pups for division and further propagation of your crop. This is possible only for cultivars that are not protected by breeder rights or plant patents.

Caring for Cut Hippeastrum

When preparing cut flowers for postharvest, three questions must be addressed: “When do I harvest?”; “How do I transport the cut flowers?”; and “What is the shelf life?”. It is preferred to harvest the stems as soon as the bud has set and has taken on color to prevent any bruising during shipping. It is important that the stem be cut at a 45-degree angle to avoid damage to the stem. After cutting off the stems, like the most basic of recipes, just add water! Hippeastrum scapes are hollow, and if left exposed to air, the tissue can quickly dry out and slow transportation of water to the bud. To remedy this, fill the scape with water and plug the opening with a soft material.

Once the stems are cut and plugged, they are ready for packing and shipping. The cut flowers must be shipped at a cool temperature of around 41F to keep the buds tight. Transportation must be quick as the flowers are perishable.  Once placed in a vase, the ‘plug’ can be removed and warm temperatures will promote the opening of the bud. Flowers can last up to two weeks after being removed from the bulb and opening completely.

Bulb Burdens

A number of diseases and pests can affect your crop. Constant vigilance is in order; you should be scouting consistently to keep your bulbs healthy. Slugs damage bulbs by chewing on emerging scapes. Control by chemical means or manually discarding them.

Soil-borne diseases such as fusarium and phytophthora rot are also a problem, especially when plants are stressed by too little or too much water. Symptoms of root disease are usually evident in stunted growth of the scape. The best preventative method for these pathogens is to limit overhead watering in the field to avoid spread. Remove the infected bulb from the crop as soon as possible.

Scouting for disease vectors in your crop is a must as insects transmit hippeastrum mosaic virus. Signs of infection include discoloration of the leaf in a mosaic pattern. Thrips are also a common pest and are vectors for tomato spotted wilt virus. Symptoms include wilting and browning of leaves. While virus infections do not normally kill the plant, they affect vigor and the overall appearance of the scape and blooms.  The only feasible means to manage viruses in the field is removing any plants showing symptoms.

New Horizons

Hippeastrum cultivars are grouped by flower type and growing habit. When selecting new cultivars, choose colors which sell best for your region in a given season, and vigorous cultivars with an attractive habit that produces multiple tall scapes during one season. Look for exciting cultivars that intrigue both the florists and the consumer.

A factor that carries a bit more weight is proper flower time. The peak times for cut flower sales are late March through early May, which includes holidays and events such as Easter, Mother’s Day, and spring weddings.

Renowned floral designer Dorien van den Berg told me that cut amaryllis are among the top arrangement flowers in the European Union and Middle East. Her favorites include:

Hippeastrum papillio
—a species with brick-colored markings on lime-green petals.
‘Aphrodite’—a cultivar with a brilliantly soft pink double.
‘Red Peacock’—a double-flowered cultivar with a deep red bloom.
In trials at Longwood Gardens, I found the following varieties offered variety in arrangements:
‘Miracle’—quick to bloom and showy with crown of vibrant trumpet flowers.
‘Inferno’—large bloom of double ember-colored petals, often lustrous in direct sunlight.
‘Bellisimo’—wonderful pink flowering bulb with large scapes that promises to be a good cut flower cultivar.

Much like following a recipe, having the proper ingredients, such as favorable environmental conditions, correct storage, and willingness to explore, can result in a great Hippeastrum cut flower program.

C. LaDell Sumpter

Virginia Tech

C. LaDell Sumpter, a recent graduate of Virginia Tech, is a college intern at Longwood Gardens in Kennett Square, Penn. He works with forcing bulbs such as daffodils, tulips, and Amaryllis. Contact him at [email protected]