Building the Jungle

After opening our doors in 2003, we thought it would be appropriate and interesting to reflect upon the progress of this Jungle built from scratch. It is also an opportunity to review the means and methods of the horticultural decisions that were made during the two-year process of landscape installation.

The design of the 18-acre gardens was based on a number of factors. The successful horticulture programs developed at Parrot Jungle and Gardens (Jungle Island’s original site), combined with the landscape design and unique nature of our new site, facilitated the growth and evolution of Jungle Island's lush, tropical landscape.

Jungle Island, one of Miami’s premier attractions, has earned the U.S. EPA’s Pesticide Environmental Stewardship Program’s Gold Level designation. This mark is awarded to organizations that have made a conscious commitment to adopt technologies and practices that reduce pesticide risk to human health and the environment.

Horticultural Programs

The Integrated Pest Management program (IPM) on Jungle Island was developed over a period of 15 years and resulted in an insect control program that used a minimum of pesticides (none restricted). Biological controls were introduced with good results, for example Nosema for Lubber Grasshopper control, and Bacillus thuringiensis to control chewing insects and mosquitoes. The philosophy behind the IPM program was based on another program, Plant Health Care (PHC), which utilized strict control of irrigation, the extensive use of park-produced compost, constant mulching, and specific cultivation techniques.

Soil

Watson Island is an 86-acre island that was created from the limey sand and rock that was excavated to create the  ship channels for the adjacent Port of Miami in the early 1900’s. 

The top 10 feet of this island consists of sand with varying amounts of shell or limestone fragments. The first 4 feet contains an organic component of up to 13%, which has accumulated on the island over time through the natural decomposition processes that accompany the growth of vegetation or naturally occurring ground cover. Originally, the site was about 8 feet above sea level. Since Watson Island is classified as a flood zone, buildings are mandated to be built at 11 feet above sea level. This necessitated the importation of almost 27,000 tons of structural fill to be placed under all of the park's buildings and venues.

Before the structural fill was placed, the existing fill was removed down to 4 feet above the water table, and stockpiled to be used as landscape soil.
The indigenous soil was used as a landscaping-medium for several reasons: the island never seemed to flood in a heavy rain, therefore it had excellent drainage characteristics, and with excellent drainage comes excellent aeration. 

Many different species of trees and palms were already successfully growing in this soil; and when a different soil type is layered onto another soil type, a perched-water table can be created that will not allow water percolation to take place until the upper layer of soil is totally saturated. This can be deadly to many species of plants. Finally, the cost savings of not exchanging the landscape soil was tremendous.

Compost

The park’s original site had been a licensed composting facility that composted 100% of the park's organic waste, with the exception of food waste. This compost was then returned to the park as top soil and plant nursery soil media. During the last two years in Pinecrest, more compost was made and stockpiled, with the purpose of utilizing it at the new park to help establish the new landscaping.

During the transition to Jungle Island, we moved about 400 yards of this resource to the Island, and began to use it as a soil conditioner and top-dressing.
The purpose of using the compost was to inoculate the soil with beneficial microorganisms and mycorrhiza (fungi that have a symbiotic relationship with plant and tree roots) and to further add organic material to the existing soil, aiding in moisture retention.

The micro flora and fauna that occurs in the compost functions as a constant nutrient source to the plants. They are supplied in small enough amounts that there is not a large burst of nitrogen into the plants, which would merely serve to attract plant pathogenic insects. This is a very important part of reducing our reliance on pesticides and fertilizers.

Compost and mulch are also utilized to secure the sides of berms to prevent erosion, allowing the eventual vegetative cover to do the work of artificial stabilizing materials. This application alone saved considerable cost by not having to install ground cloth and rip-rap (large rocks used to stabilize slopes).

Mulch

This mulch is derived from arborist tree-trimming operations. Any clean mulch is accepted and used almost immediately as a ground cover. This mulch has several purposes: it has excellent aesthetic qualities; it holds down weeds; and it insulates the ground, thereby reducing soil water evaporation. If the upper horizon of the soil is cool and moist, there will be more beneficial organisms and tree-root-hairs in this zone. Mulch continues to decompose further adding organic material and nutrients to the soil. It also encourages earthworms to live in this zone, which will improve soil aeration and add more nutrients to the soil.

Green Mulch

Many landscape plants are short-lived or need to be cut back on a regular basis. Certain plants accumulate nutrients that can be infused back into the soil when they are cut down and used as mulch. Leguminous plants accumulate nitrogen. Tithonia diversifolia, Mexican Daisy, is a plant that accumulates phosphorous. When we cut back these plants, the resulting plant material is utilized as mulch and in the case of the Mexican Daisy, it grows back as a nice landscape plant.

Irrigation

Without irrigation, a collection of tropical plants will not grow and thrive on Jungle Island; there is too much wind and of course, heat. To reduce evaporation, irrigation is only done at night, and the sprinklers are designed to throw as large a droplet as possible. The larger the droplet of water, the less actual surface area per droplet, and less evaporation per gallon of water. The droplet is also heavier and less wind throw will occur, leaving fewer drier landscape areas due to windy conditions.

There are several large water features on Jungle Island and there is a mechanical filtration system to filter out organic matter, etc. Instead of pumping-out the resulting sludge and waste into a septic tank for off-site removal, we pump the sludge into a biofiltration pond where the heavier sludge will precipitate-out and the excess water is pumped back into the irrigation system. The sludge is periodically removed and used as a soil amendment.

There are areas of landscaping that were designed to have only temporary irrigation for a couple years to get the plants established and growing. These plants, once established, will be able to live on rainwater and most likely will be taken-off the irrigation system.
Water harvesting is also being considered for future irrigation use.

Cultivation Techniques

The selective pruning of leaves and inflorescences on many plants, for instance bananas, palms, Heliconias, is a proven way to mitigate insect pressure. Hand-picking leaves off Geiger trees that are full of Geiger Tortoise Beatle larvae is a more efficient, cost-effective, and environmentally-sound method of controlling these insects. There are many species-specific ways to nurture plants, which in the long run, are more efficient and better for the environment.

Plant Selection

There are literally thousands of species of tropical plants growing on Jungle Island. The key to the plant selection was utilizing plants that are native to areas with climatic and soil conditions similar to ours’. This obviates the need for fertilizer. These plants normally grow very well under our composting and mulching regime. There would also be fast growing and usually short-lived (r-selected species) plants and trees that would be used to create an immediate canopy or vegetative barrier. Planted amongst these would be slow-growing and long-lived (k-selected species) plants and trees that in time, would become the main horticultural component of the Jungle.

Canopy Trees

Before Jungle Island took root on Watson Island only about 150 trees were growing there. After a site analysis, it was determined that, to save as many trees as possible, we would move them off the site to a holding area and then back to the island when construction allowed. Of the original 150 trees, 80 were unsalvageable due to poor trunk structure, extensive trunk damage or rot, or they were in the invasive exotics category. The 70 trees that remained were successfully moved offsite and then back on; a handful of trees were actually moved three times due to changes in site design. Two years later we had 100% success. Moving and maintaining the full-size trees proved to be very cost effective and productive, when compared to transporting pruned, smaller trees (due to size regulations of moving them down a public thoroughfare) and waiting years for a new canopy to grow.

In the initial stages of construction, a majority of the largest trees were replanted on the site and protected from the ongoing construction. These horticultural “islands” were also under-planted with smaller trees. These became field nurseries as we selected trees when needed. This limited the amount of time a plant was out of the ground as it was moved into place during the construction and landscaping phases, thereby reducing shock and damage to the tree.

Design and placement of the canopy trees was done along an east-to-west configuration, and to the south of the concrete trails. This was done to provide shade for guests of the Jungle and mitigate the summer ‘heat island’ effect.

Grass and Lawns

There are two lawn areas on Jungle Island: one is in Flamingo Lake and the other is our Jungle Outpost. This presented a number of challenges. Flamingo Lake is a water exhibit with fish surrounded by lawn and trees with a flock of breeding Flamingos. At issue is keeping the lawn healthy through a method that is safe for all of the resident animals. The exhibit is in a basin and all chemicals used on the lawn will eventually run-off into the lake. The Jungle Outpost does not have animals but is used for picnics and other public events. A lawn and the underlying soil that is walked upon, at times by thousands of people, is typically compacted by all the activity and is difficult to keep in good condition.
The issues of keeping the lawns green, disease free, and able to deal with soil compaction problems, was resolved by utilizing what grows naturally on Watson Island.

There are many species of grasses and herbaceous plants that grow freely (some call them weeds) in heavily trafficked areas and do quite well under this kind of pressure. Many of these plants are natural nitrogen fixers and look quite green. We have allowed these plants to grow into the lawns with very good results. Eventually, after studying the growth habits of the different species, we decided to select the best plants to grow and remove the others. The ability to grow a resilient lawn that does not require pesticides or fungicides seems to be an attainable possibility.

Results

Today, through a holistic approach to landscape development, we have successfully built a jungle. In the first year the Jungle was open, the foliage and the tree canopy had grown many times over. We have been planting epiphytes; Stag horn ferns of several species, other species of ferns, and orchids are now established on our trees. We are increasing our collection of Bromeliads, Bananas, flowering trees, and Palms. An incredible collection of Cycads has been donated to us. These fossil plants are in the gardens and have successfully established themselves.

Through stable climatic conditions (the winter low temperatures have mild), better soil, and a more efficient landscape layout, the gardens have rapidly matured and become a horticultural showcase.

Jungle Island is a member of the Green Scapes Alliance of the U.S. Environmental Protection Agency's Environmentally Beneficial Landscape program and a member of the EPA’s Pesticide Environmental Stewardship Program. This project has shown that a holistic approach to landscape-site development is a very cost- effective and environmentally sound method by which a landscape, garden or even a jungle can successfully established.