No Ordinary Mum

Come see our Thousand Bloom Chrysanthemum now in the East Conservatory!

Do you hear the word chrysanthemum and picture those simple household flowers from the local garden shop? At Longwood Gardens, we take the ordinary mum and make it extraordinary, turning it into a work of art—the Thousand Bloom Chrysanthemum!

We started our Thousand Bloom Chrysanthemum from vegetative cuttings of Chrysanthemum x morifolium ‘Sosono no Tsuki’ in May 2010. In order to grow this year’s mum, we had to overcome the challenges of heat, rain (Hurricane Irene!), stink bugs, and the 12’ 7” wide door of the East Conservatory (which was just barely wide enough to bring the mum through).

Each year, we grow two plants to help ensure we can reach our goal of more than 1,000 blooms on a single plant. Each month, both plants are repotted, pinched, tied, and framed as needed. In the end, we will use only one of them for display in the Conservatory. Here is a slideshow that documents the mum’s growth over the past year. Please enjoy!

MONTHLY PROGRESS:

May 2010: Several cuttings are taken from stock plants grown at Longwood. After two weeks they are brought into the greenhouse to harden off and are then transplanted into 4” pots.

June 2010: The plants are transplanted into larger pots and have their stems scratched (scarification) with a knife to apply rooting hormone. This creates a larger root system to support the enormous top growth.

Stem scarification

To prevent flowering, the plants are placed in a greenhouse lit at night. During  summer, the plants continue to grow and are pinched at around 2” tall to encourage 14-18 shoots by first pinching. We continue to pinch every 6-8 leaves depending on stem length.

December 2010: Two plants are selected and placed into final growing containers that are custom made by Longwood’s carpenters. The containers are made with dividers so that the volume of soil can increase as the plant grows. The main metal support structure is also put into place and will extend as the plant grows. Stems are bent down to begin forming the structure of the final plant.

February 2011: The first set of framing is applied to the main support structure. Each frame layer is constructed on site and is made of fiberglass rods wrapped in black tape. The tape makes the rods easy to handle and also adds a bit of friction to help us twist the ties used to hold the stems to the rods. The fiberglass rods are joined by custom-made connectors and tied together with zip ties.

March 2011: Another set of framing is added, increasing the overall width by about 5-8″. To increase the number of branches, we pinch and then tie each stem to the fiberglass frame with a twist tie.

After we place the mums into their final growing container, we continually coax them to grow bigger—with pinching (to encourage branching) as well as proper watering and fertilization techniques (to encourage healthy growth). The plants are monitored for any signs of disease or insects that are treated as needed.

Each month, depending on growth, the fiberglass framework is extended to help encourage growth and to continue to support the stems as we reach our final size.

July 5, 2011 – Before framing

July 7, 2011 – First layer tied

July 13, 2011 – Over half way

July 15, 2011 – All stems tied

September 8, 2011 – Stems are evenly spaced and tips lined up

September 2011:As the buds begin to form, we begin to disbud the mums. This process involves taking all of the smaller side buds off and only allowing the main center bud to continue to grow, resulting in one beautiful  4-5” flower on each stem.

Disbudding - removing the smaller side buds

Placing each flower into a Rindai support

October 2011: Less than one month before the beginning of Chrysanthemum Festival, we select our display plant and begin final flower placement. The frame is custom made each year based on the plant’s size.

Longwood’s Chrysanthemum specialist and her crew of interns, international students, seasonal, and part-time staff members begin by arranging the flowers on the top first and working their way down, making sure each row is placed perfectly in concentric rings and that each flower is lovingly placed into a Rindai support to properly position it.

View of the one stem, main support frame, and perforated pvc pipes (in place to aerate the soil)

The process of placing the flowers takes about 10 days, at the end of which we finally know the answer to everyone’s question, “HOW MANY BLOOMS THIS YEAR??” After achieving 991 blooms on the 2010 Thousand Bloom Chrysanthemum, our goal was to beat that number. And we did!!!  This year’s total is 1,167 flowers!!!

As you can see, a lot of time and effort goes into producing the Thousand Bloom Chrysanthemum. It’s on display now in the East Conservatory. Make sure to kneel down to see the one stem coming from the soil!

The Chrysanthemum Festival, October 29–November 20, showcases thousands of amazing chrysanthemums throughout the Conservatory, including Cascade style, topiaries, single stem mums and the Thousand Bloom Chrysanthemum.

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Mum’s the Word: Longwood Grows Mammoth Mum

Longwood’s Largest Thousand Bloom Chrysanthemum Ever on Display in the East Conservatory

What is it?

The Thousand Bloom Chrysanthemum (known in Japan as Ozukuri) refers to a technique, originating in China and expanding to Japan several hundred years ago, for growing an extremely large Chrysanthemum, with a goal of producing the maximum number of flowers possible on a single plant.

If that doesn’t sound difficult enough, the technique also requires that there is only a single bloom on the end of each individual branch; none of the flowers on the sides of the branch is used.  And to further complicate matters, each flower must be perfectly placed in concentric horizontal rows on a dome-shaped frame!

The largest specimen recorded in Japan had over 2,200 flowers—only a few growers in the entire world have been able to produce a plant that large.

How do we do it?
First, we choose a suitable cultivar—one that has large flowers, the ability to produce long stems, can grow well under a wide range of temperature and light conditions, and the ability to produce 3-4 branches each time the stem tip is pinched. The mum variety used this year is ‘Kenbu’, a Japanese variety that produces large, white, fully double flowers on long stems.
Our grower, Yoko, started the plant from a cutting taken in July 2008, and grew the plant in a greenhouse for about 15 months, enabling it to grow large enough and produce enough stems to be shaped into a Thousand Bloom.

During winter months, when days were short, supplemental lighting was provided to prevent the plant from flowering, and to insure the stems grew long enough.  The plant was watered very carefully, fertilized frequently, and the container size was increased multiple times to provide enough space for good root growth.  Temperatures were kept as close to 65-70 degrees Fahrenheit as possible to encourage continual growth.

Thousand Bloom Chrysanthemum just prior to its move to the East Conservatory

Yoko and her team pinched it (removing the shoot tip) periodically to cause the side branches to grow out. Every time a stem is pinched, 3-5 new branches will form below the pinch. The number of flowers on the finished specimen is dependent on the number of branches, since ultimately only one flower will bloom at the end of each branch.
In late September, the shortening day lengths caused the plant to produce flower buds.  When the flower buds are still very small, Yoko and her helpers removed the ones that formed on the sides of each branch, leaving only the bud at the end of each branch.

In mid-October, the metal frame was installed by a Dave B., a metal worker from our Maintenance Department.  The ribs and horizontal wires that create the dome shape used to hold the flowers in their proper positions was prefabricated by Dave B and his colleague Dave T.  Special wire circles are attached to each wire post to provide additional support for the flowers.  The overall frame size is determined by how long the branches are (the tips of each branch must be long enough to reach the frame) and how many branches there are.  It takes several days to install the frame.  The frame on this year’s Thousand Bloom is about 9 feet in diameter at the base.

Yoko and a member of her team at work, placing each flower into the dome-shaped frame.

Once the frame is in place, Yoko stopped watering the plant, allowing it to wilt slightly. This makes the stems more flexible so they can be moved easily without breaking.  She then brought together a team of four gardeners to place the flowers in their proper positions on the frame.  First, each flower is placed in a soft fabric sleeve to protect it during handling. Then, starting at the top of the frame, the flower buds are attached to the wire supports—resulting in perfectly spaced concentric rings of flowers. Once the flower buds are in place, the sleeves are removed so the flowers can fully open.
When the flower arranging was done, the Thousand Bloom was placed in its final location in the East Conservatory to be enjoyed by Longwood’s guests.

This year, Longwood has grown its largest Thousand Bloom ever—and one of the largest ever grown in the United States—featuring 718 perfect blooms and measuring more than 8 ft in diameter! This magnificent chrysanthemum is on display now through November 22.

Longwood would like to thank Japanese Master Growers Mr. Katsuo Ito, Mr. Minori Yusa & Mr. Tadashi Imafuku for sharing their knowledge and skills with us and helping us to produce our classic mum forms.

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