Repotting the Tiger Orchid
On June 28, Aquatic House curator Dave Horak and members of the Horticulture staff repotted BBG’s Grammatophyllum speciosum, commonly known as the tiger orchid. Considered to be the world’s largest orchid species, the plant on display at BBG is a beautiful specimen weighing approximately 300 pounds.
The basket holding BBG's Grammatophyllum speciosum, commonly known as the tiger orchid or great orchid, needs to be replaced. Years in the hot and humid conditions of the Aquatic House has caused the basket to rot, and the orchid needs to be repotted in a new one.
The orchid was purchased for BBG’s orchid collection in 1998 from the estate of Don Richardson, a prominent orchid specialist and head grower for Greentree, the 400-acre estate of Mr. and Mrs. John Hay Whitney in Manhasset, Long Island.
BBG’s Grammatophyllum speciosum has only blossomed twice since coming to the Garden; blooming requires a tremendous amount of light and heat that isn’t always easy to provide given Brooklyn’s winters, even in a glasshouse. The short day length and lower light intensity of this latitude makes blooming an uncommon event here; the last time it flowered was in 2008.
Tiger orchid (Grammatophyllum speciosum) in bloom. Photo by Dave Allen.
In its natural habitat in tropical Asia, the tiger orchid grows as an epiphyte in crotches of sturdy trees, where its roots intertwine to capture leaf litter and other sources of nutrients. In BBG’s Aquatic House it is planted in a wooden basket and fertilized frequently. Over the past five years the basket had begun to deteriorate, threatening to drop this heavy plant into the pool below.
Plants living in the pool below the Grammatophyllum speciosum must be moved out of the way before the plant can be lowered.
Aquatic House curator Dave Horak runs a support line that will be attached to the basket to lower it.
The hook of the support rope is in place and ready to bear the weight of Grammatophyllum speciosum, considered the world's largest orchid species.
Curator Dave Horak (in pool) and BBG staff discuss how to best lower the orchid to the pool, where it will be repotted.
Dave Horak guides the orchid to pool level, where the old basket will be cut away and the orchid repotted in a new, rot-resistant basket.
Curator Dave Horak inspects the plant and moves the support table into place.
Cinder blocks are put in place to keep the orchid out of the water as it is repotted.
BBG’s Dave Horak and Uli Lorimer guide the orchid on to the platform.
A shade cloth doubling as a drop cloth is placed in the pool under the orchid and surrounding area to catch any debris that may fall once the orchid is removed from its basket.
Curator Dave Horak carefully cuts through the long metal screws holding the old orchid basket together.
After cutting through the old basket, the orchid is lifted so that the lower part of the basket can be removed. Since the plant has grown through the top slats of the basket in several places, they have been left in place and wired to the rigging to help support the plant as it is lifted. Even with the top slats in place, the entire weight of the plant is borne by the stemlike pseudobulbs that have grown through them.
As the orchid is carefully lifted out of the old basket, the roots and pseudobulbs are examined and decaying material removed.
The underside of Grammatophyllum speciosum.
Once the old basket is down, it is easy to see the extent of the rot and broken slats.
Senior arborist Chris Roddick mans the hand crank and guides the line used to raise and lower the plant with the help of grounds foreman Leonard Paul and arborist Travis Wolf.
Grammatophyllum speciosum from above as it awaits repotting.
The new basket was constructed by David Mueller, a BBG volunteer, and is made of ipê (Tabebuia species), a heavy, neotropical wood very resistant to insects and rot. The repotting of the orchid was a long process taking seven hours.
The new basket that will house the orchid is assembled by senior foreman Lou Provost and Dave Horak.
Charcoal is added to provide the “bones” of the potting mix; as other components of the mix break down, slow-decomposing charcoal allows sufficient drainage and air exchange for the survival of epiphyte roots, prone to rot in dense soils.
After adding charcoal, fir bark is added to the new basket to help with aeration and drainage.
Fresh potting medium in the new orchid basket.
The new orchid basket is lowered onto the support table in the pool.
BBG’s Dave Horak and Uli Lorimer center the orchid above the new basket and ready it to be lowered into place.
The orchid is successfully lowered by a hand crank into the basket, and Dave Horak and Uli Lorimer carefully remove the remaining slats from the old basket to allow the plant to grow without constriction.
Curator Dave Horak carefully measures and attaches the metal wires that will suspend basket.
The team begins to lift the orchid in its new basket, checking to make sure it is level and balanced.
Dave has decided to move the orchid a few feet away from its original position, so a new support line needs to be added. The team sets a ladder in place for arborist Chris Roddick, who will climb up and set the line.
Success! The Grammatophyllum speciosum is hanging beautifully in its new basket in the Aquatic House.