Grow Ornithogalum In The Greenhouse

'Orange Star Improved' ornithogalum

Potted sun stars (Ornithogalum dubium) are nearly unknown in the U.S., but in Europe, they are prized and sought-after pot plants, consistently fetching top price at the flower auction.

O. dubium is a geophyte, or bulbous perennial plant. Depending on the cultivar, the bulbs produce five to eight deep green, glossy leaves that are arranged in rosettes. Cultivars suitable for pot culture produce short, linear foliage ranging in length from 3 to 4 inches with a width of less than 1 inch. Strong pot cultivars produce more than one flower shoot per bulb. Each sturdy shoot grows 5 to 7 inches tall, bearing a compact cluster of brilliant flowers. Some clusters may produce up to 20 flowers.

Sun stars come in orange, yellow and white. Potted ornithogalum can be used indoors to brighten up the house. These plants are also ideal for window boxes, patio containers and planters early in the season, as soon as temperatures remain above freezing.

Ornithogalum Hybrids Are Compact And Colorful

Perhaps the best-performing pot cultivar for both bulb sales and crop performance is Ornithogalum ‘Orange Star.’ The majority of these bulbs are sold to the European markets and more recently to the markets in China and throughout Asia. Sales to the U.S. are still marginal compared to the other markets. Ornithogalum ‘Orange Star’ is an improvement over cultivar No. 511, which still is considered a reliable and high-performing plant. ‘Orange Star’ is more compact, making it better suited for smaller pot sizes. The newest additions to this product line are O. ‘Fire Star’ and O. ‘Orange Star Improved.’ Both new cultivars maintain a compact growth habit, but the pigmentation of ‘Fire Star’ is more pronounced — a sparkling, vivid orange. New yellow-and-white-flowering ornithogalum hybrids will be released soon.

Store Bulbs Properly To Avoid Blue Mold

Check your bulbs for problems upon arrival at your greenhouse. They should be plump and free of mold and other signs of disease. Take the bulbs out of the box and place them into a well-ventilated area. The proper storage temperature is 79°F to 82°F, which is considerably warmer than that at which most other bulbs are stored. The bulbs need to be protected from direct sunlight and relative humidity should be moderate, ranging from 50 to 60 percent.

In my experience, the most common problem is excessive relative humidity causing bacterial soft rot (Erwinia carotovora) and blue mold. A slight infestation with blue mold is unsightly, but does not affect plant growth. Excessive amounts of blue mold, however, can damage the bulb tissue and may lead to deformed foliage and blooms. Comparatively, bacterial soft rot is a very serious problem.

Bulb Preparation Varies With Geographic Location

To control plant development, growers should prepare the bulbs before planting. This preparation or flower induction process takes place in a cooler, temperature-controlled environment and is very similar to that of dry vernalization of tulips. The bulbs are moved into a space with a set temperature point of 55°F and a relative humidity of 60 percent.

Keep the bulbs in this environment for three weeks or until roots start to develop. During this stage air circulation is particularly important. Once the roots start to grow, it’s time to plant — so plan accordingly. Planting time varies depending on geographic location and the grower’s preferred method of production. Suppliers ought to give specific instructions based on production protocol and geographic location.

Prevent Fungal Infections With Adequate Spacing

A number of commercial potting mixes can be used for growing ornithogalum. In general, the media should be well draining with excellent aeration. My preferred bulb mix contains washed sand, peat moss and vermiculite. Apply lime to the media to adjust the pH to a range of 5.5 to 6.

The new cultivars of O. dubium are compact plants that show best in small pots. Plastic pots work fine, but I prefer to grow them in clay pots. The suggested sizes and number of bulbs per pot are as follows: 3-inch pot, 1 bulb; 4-inch pot, 3 bulbs; 5-inch pot, 5 bulbs. The bulbs are planted just below the surface of the potting mix and should be covered by approximately 0.25 inch of media, slightly less is better.

The pots should be watered and moved into the greenhouse. Initially they can be kept on carts or spaced pot-to-pot on the bench. As foliage develops, though, pots need to be moved to final spacing. A spacing of 1 to 1.5 inches between pots is sufficient. Choosing a slightly wider spacing increases airflow, which may prevent fungal infections such as Botrytis.

Water Evenly And Feed Lightly For Successful Growth

Sun stars require firm water management and even moisture during the growing stages until flowering. The potting media needs to be well drained, allowing for excellent aeration. Waterlogging and underwatering are common troubles in the greenhouse.

Intermittent drying out of the media causes significant damage to ornithogalum. When the media becomes too dry, the delicate roots desiccate. Plants usually do not recover from a damaged root system. Fungal infestations start from the damaged roots and slowly kill the affected plants.

Both drip irrigation systems and hand watering work to alleviate this problem. Watering should be limited to the early morning. Otherwise, water might stay in the rosette too long, resulting in rotting of the plant from the base. For most of the production cycle, watering two to three times per week is sufficient.

Ornithogalums are light feeders. Overfeeding quickly becomes a problem that is most commonly expressed by brown tips on the foliage. Using an appropriate water/fertility program results in dark-green foliage, which is an improvement over the old varieties. Yellowing and browning of the tips was a common problem in older varieties. This issue was successfully eliminated through breeding.

A complete 17-10-27 liquid fertilizer is recommended for ornithogalums. I had good experience using Excel 15-05-15 Cal-Mag complete water-soluble fertilizer. A 75 to 100 parts per million nitrogen fertilizer solution is sufficient. Keeping an eye on salts is very important and you should monitor your electrical conductivity (EC) frequently. The optimal EC is between 0.8 to 1.2 meters per second.

Use Warm Temperatures And High Light

Ornithogalum flourishes at moderate temperatures and high light conditions. The optimum temperature range is 62°F to 71°F. They grow best at moderately-warm temperatures and high light.

Growing ornithogalum at low temperatures is possible (and an option for conserving fuel), but bench time is significantly increased. Depending on your growing temperature, the production cycle for the crop is between 100 and 120 days, even longer for low-temperature growing.

Especially in the northern temperate regions, supplemental light is shown to ensure excellent crop development. High light in combination with high temperatures, however, is detrimental to the crop. In southern regions of the U.S., as well as with the late-season flower dates of northern regions, greenhouse shading may be necessary.

The new ornithogalum introductions are genetically dwarf cultivars and do not require plant growth regulators (PGRs) under optimal growing conditions. Under low light, or when speeding up production time, an application of GA3 will produce good results. You can expect to reduce your bench time by two
weeks. The PGR is applied as a spray at the four-leaf stage. For the proper
concentration, inquire with a supplier or extension agent.

Leave a Reply

4 comments on “Grow Ornithogalum In The Greenhouse

  1. Love these little flowers , but can’t find a source to purchase bulbs . Are there any online sites you know of ?

More From Varieties...
crider-rd2-internal_Rough-Brothers_featured

July 1, 2015

Rough Brothers Is Acquired By Gibraltar Industries

RBI Solar Inc., Rough Brothers Manufacturing Inc. and affiliates have been acquired by Gibraltar Industries, a manufacturer and distributor of products for residential and industrial markets, for $130 million. Capitalizing on its 80 years of design-build experience and leadership as the largest greenhouse manufacturer in North America, Ohio-based RBI has established itself during the past five years as North America’s fastest-growing provider of photovoltaic (PV) solar racking solutions. The transaction will enable Gibraltar to leverage its expertise in structural metals manufacturing and materials sourcing to meet global demand for solar racking solutions. The company also announced that it anticipates its second-quarter 2015 financial results will be in line with its previous expectations. “Acquiring RBI is an important step in the transformation of Gibraltar into a company with a higher rate of growth and best-in-class financial metrics,” says Gibraltar CEO Frank Heard. “This acquisition directly aligns with key end markets and product platforms […]

Read More

June 30, 2015

Opportunities Abound For Women In Horticulture, Says Dosatron International’s Lela Kelly

My love for horticulture goes back to my grandparents who were farmers in upstate New York. My family’s involvement in agriculture left a lasting impression that has spanned decades, and still drives my passion for our industry today. I started my career in horticulture when I owned a greenhouse, nursery and garden center in Sayville, Long Island, N.Y. We specialized in ground cover production, later branching out to producing perennials and bedding plants.     I then went onto wholesale hard goods distribution. In the 1980s, I was the first woman salesperson on Long Island. What an eye opener that was! New York is a very special place, different from anywhere else in the country. You cannot imagine how difficult it was walking into greenhouses and nurseries as a woman, in a man’s world. Luckily, I grew up in New York City in an Italian family, who taught me great […]

Read More
Medal of Excellence Award

June 30, 2015

Get To Know The 9 Variety Finalists For Editor’s Choice And Industry’s Choice Awards

Greenhouse Grower‘s Evening Of Excellence reception is rapidly approaching. Here, you can learn more about the varieties that are finalists for the Medal Of Excellence Editor’s Choice and Industry’s Choice Breeding Awards. Thank you to the 2015 sponsors of Greenhouse Grower‘s Medal Of Excellence Awards, Landmark Plastic, Nufarm and Stockosorb. Editor’s Choice Asclepias ‘Monarch Promise’ (Hort Couture) Basil ‘Balsamic Blooms’ (EuroAmerican Propagators) Celosia ‘Dragon’s Breath’ (Sakata Seed) Dianthus Jolt Series (PanAmerican Seed) Salvia Grandstand Series (Green Fuse Botanicals) Scabiosa ‘Kudos Pink’ (Hishtil Nurseries) Industry’s Choice Basil ‘Balsamic Blooms’ (EuroAmerican Propagators) Bidens BeeDance Series (Suntory Flowers) Celosia ‘Dragon’s Breath’ (Sakata Seed) Dianthus Jolt Series (PanAmerican Seed) Lobelia ‘Starship Deep Rose’ (Kieft Seed) Vinca Valiant Series (PanAmerican Seed)     Join us Monday, July 13 in Ballroom 2 at the Columbus Convention Center to find out which varieties will receive the coveted awards. The reception begins at 5:15 p.m. and the ceremony […]

Read More
Latest Stories
Medal of Excellence Award

June 30, 2015

Get To Know The 9 Variety Finalists For Editor’s …

Greenhouse Grower‘s Evening Of Excellence reception is rapidly approaching. Here, you can learn more about the varieties that are finalists for the Medal Of Excellence Editor’s Choice and Industry’s Choice Breeding Awards. Thank you to the 2015 sponsors of Greenhouse Grower‘s Medal Of Excellence Awards, Landmark Plastic, Nufarm and Stockosorb. Editor’s Choice Asclepias ‘Monarch Promise’ (Hort Couture) Basil ‘Balsamic Blooms’ (EuroAmerican Propagators) Celosia ‘Dragon’s Breath’ (Sakata Seed) Dianthus Jolt Series (PanAmerican Seed) Salvia Grandstand Series (Green Fuse Botanicals) Scabiosa ‘Kudos Pink’ (Hishtil Nurseries) Industry’s Choice Basil ‘Balsamic Blooms’ (EuroAmerican Propagators) Bidens BeeDance Series (Suntory Flowers) Celosia ‘Dragon’s Breath’ (Sakata Seed) Dianthus Jolt Series (PanAmerican Seed) Lobelia ‘Starship Deep Rose’ (Kieft Seed) Vinca Valiant Series (PanAmerican Seed)     Join us Monday, July 13 in Ballroom 2 at the Columbus Convention Center to find out which varieties will receive the coveted awards. The reception begins at 5:15 p.m. and the ceremony […]

Read More

June 24, 2015

Perennial Container Combos And New Intros Shine At 2015…

Despite a rainy start to the day, more than 300 perennial enthusiasts showed up at 2015 Darwin Perennials Day to see the latest perennial introductions first-hand and connect with some of the best suppliers in the business.

Read More
2015 Readers' Choice

June 24, 2015

The 2015 Readers’ Choice Finalists Up Close And P…

You’ve narrowed the Readers’ Choice Finalists down to top picks in the Annuals, Perennials and Best of the Rest categories. Now it’s time to pick the overall winner. Here’s a closer look at the three finalists to help you make your choice. Then join us during Cultivate'15 at Greenhouse Grower's prestigious Medal of Excellence reception on Monday, July 13, where we will reveal the winner.

Read More
WavePetunias-GrowIt_contest_featured

June 18, 2015

Wave Petunias Sponsors Photo Contest Through GrowIt! Ga…

The gardening season is heating up and the Wave Petunias Team wants to see the #WildestWave. The popular plant brand has joined forces with the GrowIt! Garden Socially app to host a two week contest in June that encourages Wave Fans to share and rate photos of their favorite Wave Petunias. The grand prize is a $100 gift card to the garden center of the winner’s choosing. “We are excited to work with GrowIt! and see our Wave Petunias tagged in cities from coast to coast,” says Claire Watson, brand manager for Wave. “Seeing gardeners’ creative photography, awarding a winner, and learning what each region likes about Wave Petunias will be extremely useful as we further promote our ‘Wow ’em With Wave’ ad campaign this season.” Gardeners can place an entry into the contest by downloading GrowIt!, filling out a profile, and uploading photos of Wave Petunias. Placing the tag #WildestWave in the photo’s comments section […]

Read More
Kaleidoscope Abelia (Plant Haven International)

June 17, 2015

PlantHaven International Launches National Campaign To …

PlantHaven International has partnered with BlueSkye Creative to initiate a national consumer ad campaign that carries across radio, video, print and social media to increase sales of Abelia Kaleidoscope.

Read More

June 17, 2015

Green Leaf Plants Plans Two Open House Events June 25-2…

Green Leaf Plants will hold two open house events this summer to give the public a chance to view trial gardens, take guided tours and learn about new varieties and programs. Both events will be held at Green Leaf Plant's facility in Lancaster, Pa. The event in July will coincide with Penn State University Extension Trials in nearby Manheim.

Read More
Suntory_EuroAmerican Propagators_CAST2015

June 17, 2015

ePlantSource Welcomes EuroAmerican to list of Partners

ePlantSource recently announced a new partnership with EuroAmerican. A complete assortment from EuroAmerican is now available on ePlantSource.com and varieties are available for sale now to customers for the 2015-2016 season. In addition to the innovative varieties included in EuroAmerican’s “Growing Opportunities — 365 Days a Year” program, Savvy Succulents, the Sunny Collection, the Senetti Collection and offerings from breeders such as Suntory and Ball Ornamentals, ePlantSource customers will also gain access to the well known Proven Winners assortment and combination containers. “During the recent California Spring Trials, I had the opportunity to sit down with John Rader at the impressive display in Ventura from EuroAmerican and I couldn’t be happier to now offer the complete EuroAmerican assortment to our customers,” says Gary Falkenstein, president/CEO of ePlantSource. “EuroAmerican is a visionary company and we are proud that they have chosen to work with ePlantSource for the coming seasons.” Catalog listings, […]

Read More
Pleasant View Gardens Open House

June 14, 2015

Pleasant View Gardens And D.S. Cole Growers Open House …

D.S. Cole Growers and Pleasant View Gardens, both a short distance away from each other in Loudon, N.H., have set July 30 as the date for their open house events. Attendance is free, but registration is required.

Read More

June 13, 2015

Bailey Nurseries’ Minnesota Expo 2015 Takes Place…

Bailey Nurseries will hold its Minnesota Expo 2015, a jam-packed event showcasing its farm and plants, on July 30 from 8 a.m. to 4 p.m. in St. Paul, Minn. In addition to farm tours, participants can enjoy new varieties, hot picks and merchandising displays, as well as attend various seminars through the day. Registration is required.

Read More
2015 Readers' Choice

June 12, 2015

Vote For Your Favorite Finalist For Greenhouse Grower&#…

It's time for you, our readers, to decide which variety is picked as the best new introduction in 2015. Voting is now open for Readers' Choice Finalists.

Read More
gapanthus DuchessofDazzle_featured

June 10, 2015

24 Plants That Can Handle Drought

These drought and heat tolerant varieties are both eco-friendly and worry-free garden performers.

Read More
hort couture_Asclepias Monarch's Promise_featured

June 9, 2015

ePlantSource And Hort Couture Partner On Variety Availa…

ePlantSource, a Colorado-based online broker of live goods to professional greenhouse growers, recently announced that the complete collection from Hort Couture is now available to be purchased through ePlantSource.com for the 2015-2016 season. The collection from Hort Couture, which offers exclusive varieties to be retailed through independent garden centers only, includes a full line of annuals, tropical, succulents, herbs, vegetables and ornamental grasses. “We are very excited to add the Hort Couture collections to what ePlantSource offers to professional greenhouse growers,” says Gary Falkenstein, president/CEO at ePlantSource. “We feel they have an exciting concept and they do a fantastic job at selecting products that bring a great draw to independent garden centers.” In making the announcement, ePlantSource touted Hort Couture’s pride in selecting varieties that will help independent garden centers stand apart from their big box counterparts, as well as its rigorous genetic evaluation program to ensure success for growers, […]

Read More
Allan Armitage At Tradeshow

May 15, 2015

Allan Armitage On Plants: We Are Alive And Well, Thank …

Allan Armitage tells why the horticulture industry is about the people, not the plants, not the marketing and not the social media, and why horticulture is here to stay.

Read More
Coleus-Campfire-BallFloraPlant

May 6, 2015

Costa Farms Releases 2015 Midseason Top Performers

Costa Farms has announced the mid-season top performers in its 2015 Season Premier Trial Garden. Its research and development team has been working to grow and evaluate hundreds of varieties and their findings have been published online.The plants presented in the report have thrived in Miami’s mid-spring conditions. Every spring, the company’s research and development team trials more than 500 varieties of annuals, perennials and tropical plants from plant breeders around the world. All of the varieties have been tested in Costa Farms’ 2-acre Season Premier Trial Garden in Miami, Fla. The team assesses the plants for abundance of bloom, crop uniformity and overall performance. Within the report, the varieties are organized by their color. “There’s one thing pretty much everyone who shops has in mind when they step into a garden center: color,” the report states. Because of that, the report is divided by hue, so everyone can zero in on their favorite. Click here to […]

Read More

May 1, 2015

18 New Grasses To Grow

Ornamental grasses fit in with the needs of today’s landscapers and consumers better than ever. Whether your customers are looking for creative solutions for patio containers or a mass planting in a landscape, some of the 18 new varieties included here are sure to meet the need.

Read More
PP&L CAST 2015 intros

April 22, 2015

6 Breeding Companies Serve Up New Varieties At Pacific …

Pacific Plug & Liner’s theme this year, Labyrinth, a conservatory of the world’s most captivating plants, was perfectly topped off (pun intended) with fascinators for the women and newsboy caps for the men. The PP&L team dressed their part to act out the gothic “conservatory of the world’s most captivating plants.” Truly, the displays looked like they practically popped out of a catalog, and the costumes were a nice touch. Retailers take heed, the fully merchandised displays at Pacific Plug & Liner are worthy of emulating. We’ll let the pictures tell the story of all the fabulous variety introductions presented at  Pacific Plug & Liner’s 2015 California Spring Trials, where Cultivaris, Cohen Nurseries, Histil Nurseries, Jaldety Nurseries, Southern Living/Sunset Collection and Pacific Plug & Liner all highlighted their 2016 introductions.  

Read More
Speedling 2015 CAST intros

April 22, 2015

Speedling Inc. Presents New Varieties From ABZ Seeds, H…

You name it, we saw it at Speedling's California Spring Trials location in San Juan Bautista, where five companies showed off their new introductions for 2016.

Read More
Danziger_Coreopsis_Solanna Glow1

April 22, 2015

Industry Perspective: McHutchison’s Vaughn Fletch…

Vaughn Fletcher with McHutchison Horticultural Distributors is part of Greenhouse Grower‘s Medal Of Excellence For Industry’s Choice Panel. Fletcher recounts some of the standout varieties he saw while visiting Danziger "Dan" Flower Farms and Beekenkamp during California Spring Trials.

Read More