Vanilla Cultivation in Southern Florida (and beyond)
BY: Alan H. Chambers, Pamela Moon, Vovener de Verlands Edmond, and Elias Bassil
Scientific Name: Vanilla planifolia
Common names: Vanilla orchid
Family: Orchidaceae
Origin: Mesoamerica
Distribution: Globally from latitudes 27°N to 27°S.
Abstract
Vanilla extract is popular around the world as an ingredient in ice cream and various other desserts. The botanical source of vanilla extract is primarily the cured beans of Vanilla planifolia. The United States is the world’s largest importer of Vanilla beans, but domestic production is minimal. Southern Florida has a favorable growing environment for Vanilla cultivation. This document includes information relevant to growers interested in establishing a vanillery.
History
Vanilla seed capsules (commonly called beans) have long been appreciated for their distinct aroma and flavor. The major commercial species is V. planifolia with V. x tahitensis cultivated to a lesser extent. Madagascar leads the world in Vanilla production with Indonesia, Uganda, India, Comores, Mexico, and other countries significantly contributing to global production. The United States is the largest importer of Vanilla beans that are further processed into vanilla extract. Vanilla extract from Vanilla beans is now widely used in ice cream, baked goods, chocolate, cosmetics, and many other products.
V. planifolia spread from its native range in Mesoamerica across the Caribbean islands, into Europe, and globally starting in the late 1500s. Colder climates relied on greenhouses to maintain this tropical species. The vines were not production outside the native range in the absence of natural pollinators. The development of manual pollination methods in 1837 and 1841 by Charles Morren and Edmund Albius, respectively, unlocked the potential of this species for commercial production outside Mesoamerica. This timely development supported expanded production in the 1850s and 1860s in response to supply constraints from Mexico. Today, clonal descendants of the original plants are grown commercially in several countries.
Vanilla has been cultivated in the United States since before the early 1900s in Puerto Rico, Hawaii, and Florida. V. planifolia was introduced from Florida into Puerto Rico twice before 1909. A vanilla industry in Puerto Rico included a grower cooperative. The USDA station in Puerto Rico conducted horticultural, breeding, and bean curing research in support of the vanilla industry. The industry in Puerto Rico grew until the 1950s when it declined after World War II as industrialization superseded agriculture. Hawaii received Vanilla as part of trade routes before 1900. Hawaii still has Vanilla production, but mostly favors tourism business models. Additionally, Florida has four native Vanilla species (V. barbellata, V. dilloniana, V. phaeantha, and V. mexicana) with naturalized V. planifolia (Figure 1). Puerto Rico has seven species growing wild (V. barbellata, V. dilloniana, V. poitaei, V. pompona, V. claviculata, V. pompona, and V. planifolia). The native Florida Vanilla species are endangered and should not be collected from natural areas without proper authorization and permitting by regulatory authorities.
Figure 1. Flowers of V. planifolia (top left), V. pompona (top right), V. phaeantha (bottom left), and V. mexicana (bottom right) growing in southern Florida. V. barbellata and V. dilloniana are leafless species that also grow in southern Florida, but flowering has not been observed in our collection.
Importance
Vanilla extract is the second most valuable spice (second to saffron), and is the world’s most popular flavor. Natural vanilla extract comes predominantly from the cured beans of V. planifolia, which is the major commercial species, and to a lesser extent from V. x tahitensis and V. pompona. The aroma and flavor profiles vary for each species and from each growing environment. These differences could be useful for a variety of applications including as food ingredients, in cosmetics, and for various other applications.
Description
Plant: V. planifolia is a fleshy, perennial vine with green stems. The vines live for many years and some species reach 60 m (200 ft) in length. The stem diameter increases as the plant matures. Vanilla is semi-epiphytic meaning it is capable of rooting in the ground and also growing on other plants without direct soil contact.
Leaves: V. planifolia has succulent, bright green leaves. Mature leaves can be variable in size ranging from 8-25 cm (3-14 inches ) long and 2-8 cm (0.75-3 in ) wide. They are lanceolate to oval-shaped with pointed tips and can survive about 3-4 years. Some types of V. planifolia have variegated leaves and are usually grown for ornamental purposes.
Flowers and Fruit: V. planifolia flowers are large and fragrant. Waxy cream-green sepals form on axillary inflorescences. V. pompona flowers are diagnostically yellow compared to V. planifolia. Flowers can reach about 6 to 8 cm (2.5 to 3in) in length and about 5 to 10 cm (2 to 4in) in diameter. Two of the petals are similar in appearance to the sepals. The third petal is modified into a lip shape. This lip-shaped petal contains two pollinia (pollen masses) and the stigma, mounted on a column. A structure situated between the stigma and pollinia, called the rostellum, effectively prevents autopollination.
The flowers are formed in axillary bunches with a few to many flowers per cluster called racemes. They first appear 2-3 years after planting a new cutting. Vanilla tends to flower on larger vines when the diameter reaches 6-13 mm (0.25 – 0.5 in). Usually one, but sometimes up to three, flowers in a cluster can open at a time, usually early in the morning. Flowering usually occurs over a period of about 2 months, once a year, but each individual V. planifolia flower lasts for only one day. Flowers of some other Vanilla species can remain viable longer than V. planifolia.
Following pollination, the ovary swells to produce a long seed capsule (bean) that can reach about 20 cm (8 in) in length and takes between 8-9 months to ripen. Vanilla beans contain thousands of tiny black, round seeds. At maturity, the bean will split open along two longitudinal seams, exposing the seeds and ruining the bean for commercial purposes.
Roots: Vanilla produces two types of roots including aerial roots and terrestrial (ground) roots. Aerial roots are generally non-branching and are formed on the stem opposite the leaves. Aerial roots primarily function to support the vine’s climbing habit and are therefore very effective at adhering to supporting plants or structures. Terrestrial roots are usually found at the base of the vine, are branched, and possess root hairs that are often associated with mycorrhizae. Like other terrestrial roots, the primary role of these roots is the uptake of nutrients and water from the soil.
Pollination
Autopollination of V. planifolia flowers is rare to nonexistent in regions where native pollinators (bees and, perhaps, hummingbirds) do not occur. Though not native, the orchid bee Euglossa dilemma (Figure 2) has become established in southern Florida and could potentially be a pollinator of Vanilla orchids. Otherwise, our observations in natural areas show that native Vanilla species will set pods in the absence of manual pollination (Figure 3). One hypothesis is that a native orchid pollinator in southern Florida could also pollinate V. planifolia flowers reducing the need for manual pollination.
Figure 2. Euglossa dilemma lured and captured at the University of Florida Tropical Research and Education center. This bee could be a pollinator of Vanilla orchids (Photo credit: Daniel Carrillo, University of Florida).
Figure 3. Bean development in the absence of manual pollination for V. phaeantha (left) and V. mexicana (right) in natural areas.
V. planifolia is generally self-compatible meaning that pollen from one flower can be used to fertilize the same flower and will lead to seed and bean development. Pollination is reportedly low (~1%) in the native Mexican range even when pollinators are present. Thus, commercial Vanilla production is heavily reliant on hand pollination.
To pollinate a Vanilla flower, the rostellum that separates the pollinia and the stigma needs to be bypassed. Pollinations should be attempted in the morning usually between 6 am and noon. Hand pollination can be accomplished using a toothpick or other narrow implement. Sectioned V. planifolia and V. pompona flowers are shown in Figure 4 to aid in describing pollination. The lower petal can be torn to expose the anthers with pollen (pollinia), rostellum, and stigmata. The rostellum is gently pushed up and away from the stigmata until the pollinia flap can be pushed towards the stigmata and make gentle contact with the stigmata. If the pollination is successful, the flower will be retained on the plant, otherwise it usually drops off in 2-3 days. Beans will rapidly begin to swell and elongate over a few weeks if successfully pollinated.
For commercial purposes, only the flowers on the lower side of the cluster are pollinated. The beans produced from here will grow into straight beans and command a premium price. If the plant is vigorous, a total of 8-12 flowers on 10-20 clusters can be pollinated. Around 10 beans per cluster is desirable.
Figure 4. V. planifolia (top) and V. pompona (bottom) flowers with anthers (pollinia), rostellum, and stigmata. The stigmata are shielded directly behind the rostellum.
Varieties
V. planifolia has not generally benefited from modern plant breeding, so few named cultivars exist. Only a single cultivar, ‘Handa’, has been patented. This variety was developed by researchers from Reunion Island, and the future availability of this material is unknown. Otherwise, a few distinguishable types of V. planifolia have been characterized. These include ‘Mansa’ types originating from Mexico and that are commonly cultivated for commercial production. There are also two types of variegated V. planifolia generally available online and grown only for ornamental purposes.
V. x tahitensis is the second Vanilla type grown on a commercial scale. Our current understanding is that V. x tahitensis is mostly V. planifolia genetically with a little V. odorata (another Vanilla species) in its ancestry. The “x” denotes that this is a hybrid and not a separate species. The genetic contribution of V. odorata to V. x tahitensis seems to be minor, but has major impacts on bean splitting and aroma. The increased anise flavor notes of this type are popular in French desserts. Cuttings claiming to be V. x tahitensis can be purchased online but our research has found that many online vendors are unknowingly (hopefully) selling V. planifolia as V. x tahitensis. Most international sources of verified V. x tahitensis are unwilling to share their material. Research is currently underway to verify and distribute verified V. x tahitensis to interested growers.
There are also risks associated with purchasing stock plants that have undesirable qualities including sterile, low yielding, or poor quality types. Many of these will produce the classically beautiful vine and flowers, but are not optimal for commercial cultivation. Unfortunately, the sources of these types are difficult to track because of the length of time it takes to obtain a mature, flowering vine. Research is currently underway to identify types that can consistently produce commercial quality beans to reduce the risk to growers.
V. pompona is commonly grown in southern Florida by hobbyists and is also commonly mistaken for V. planifolia. V. pompona is vigorous, but reportedly produces a lower quality extract. V. pompona flowers are diagnostically yellow compared to the cream green color of V. planifolia flowers.
Environmental Conditions
Southern Florida with its hot, humid climate is suitable for Vanilla cultivation. Vanilla is sensitive to cold temperatures including freezing. Therefore, a location with reduced risk of freeze events should be selected for Vanilla cultivation. Optimal rainfall for Vanilla has been reported around 170 to 280 cm per year (67 to 110 inches/year). Vanilla requires about two months of a dry season to initiate flowering. Excessively wet conditions during capsule ripening can lead to bean rot. Supplemental irrigation can be useful for establishing new cuttings and potentially for frost protection. Figure 5 shows average monthly rainfall and temperatures as recorded by the FAWN weather station at the University of Florida’s Tropical Research and Education Center.
Figure 5. Average monthly rainfall and max, average, and min temperatures for Homestead, FL. Data are averages from 10 years spanning 2006 to 2016.
Propagation
Vanilla is primarily propagated by cuttings. It is important to let cut sites heal prior to planting by leaving fresh cuttings at room temperature under low light for 1-2 days. All other factors being equal, the longer the cutting the more quickly the vine will establish and begin to flower. Cuttings that are 30 cm (12 in) long will generally require 3 to 4 years to flower while meter long cuttings should flower in 2-3 years.
Cuttings can be placed directly on top of the growth substrate (usually mulch) as soon as the cut sites have healed. Misting will help vines retain leaves and support the rapid development of new roots and shoots. The apical end of longer cuttings can be tied to a support post with only the distal 1-2 nodes in contact with the substrate. Leaves should be removed from nodes that are in contact with the growing substrate.
Tissue culture V. planifolia plants are available from a few companies. Tissue culture plants are attractive as a clean source of starting material, but will take 3 to 4 years to mature and flower. Tissue culture plants received in enclosed containers will need to be hardened in soilless mix under humidity domes and bright indirect light for a few weeks to months before they can survive in an environment with lower humidity and free-flowing air. Regular, light misting will increase the survival of young tissue culture plants.
Vanilla is not commonly propagated by seed due to germination challenges. The thick, highly lignified seed coat prevents timely germination and takes significantly longer to grow into mature plants than cuttings. In addition seed germination is likely reliant on associations with fungi or other microorganisms. Such constraints have supported the use of cuttings as the primary propagation method.
Production Methods
Vanilla vines require trellising to maximize production. Two major production methods are used. One uses “tutor” trees to provide both shade and a suitable structure on which the vines can climb. Tutor trees can be selected based on hardiness in a given location, availability, and co-cultivation considerations. This type of cultivation can be less expensive in some areas, and also naturally reduces the risk of vine death by Fusarium by increasing the distance between plants. Growers in southern Florida should consider Vanilla as a secondary crop on existing fruit trees. Figure 4 shows V. pompona growing on an avocado tree. Any agricultural inputs will have to compatible with both species under the intercropping model.
