Woody Ornamental Production

 

 

 

 

The Project
The objective of this project is to produce Asiatic jasmine ground covers so they can be harvested, shipped, and installed like turf sod - as 1 ft x 2 ft slabs. This would eliminate the intensive and expensive labor of installing containers, and provide an instant coverage like that achieved with turf sod. If the Asiatic jasmine lawn has acceptable public appeal, then its production in slabs should substantially lower the cost of installation compared to traditional container production.

This project is wholly funded by Tampa Bay Water under the direction of Mr. David Bracciano. The project has 2 phases:

Phase 1   consists of the actual production of Asiatic jasmine in slabs.
This phase was conducted at the Mid-Florida Research and Education Center at Apopka. We produced two types of Jasmine in temporary raised beds, 2-ft wide by 15-ft long, in an overhead-irrigated production area. The goal of Phase 1 was to determine the best method to produce these slabs of jasmine. We looked at four production factors: growing substrate, planting density, the use of an erosion mat, and jasmine cultivar.

From a preliminary study conducted last summer, we settled on 2 different substrates that were quite different from each other, but that produced the best root and shoot growth. The bark-based substrate is the same mix that we use to grow all woody shrubs and trees. The sand-based substrate is much closer to the sandy soil found in most of Florida.

60% bark : 30% peat : 10% sand substrate
50% sand : 25% bark : 25% peat substrate
We looked at 3 densities of planting: 6-inch, 8-inch and 12-inch spacing. With 1-gallon containers of Asiatic jasmine, a 12-inch spacing is recommended; however, these plants can take 6 months or more to fill in. In contrast, 6-inch spacing will allow the plants to fill in more quickly, and will likely produce an intact slab more quickly. However, the more densely the bed is planted, the more plants are required, increasing the initial cost.
The bed on the left is spaced at 12 inches, while that on the right has 6-inch spacing.
We  also included a biodegradable erosion mat in half of the beds to see if it helps hold the slabs together, further decreasing production time. The mat is made of woven straw, and will break down after the jasmine slabs are installed in a landscape.
A biodegradable erosion mat is included in some beds. The mat may accelerate slab production.
We  also looked at 2 different cultivars of Asiatic jasmine. `Minima' is a more common jasmine groundcover, and has been used in Florida for decades. The drawback of ‘Minima' is that it doesn't root well along the stems. `Texas Longleaf' was introduced in Florida about 10 yrs ago, and it has more narrow, lighter green leaves than ‘Minima' with an attractive copper color on the new growth. ‘Texas Longleaf' tends to root at every leaf node, which should make it easier to produce a harvestable slab.
‘Minima'dwarf Asiatic jasmine
‘Texas Longleaf' Asiatic jasmine
The raised beds were planted the third week of March 2001. The 'Minima' group was harvested in January 2002. The beds were cut into 1 ft x 2 ft slabs, stacked on pallets, and shipped to a model home in Fish Hawk Ranch in the Eagle Ridge Subdivision in  Southeastern Hillsborough County.  A month later, in February 2002, slabs of the cultivar ‘Texas Long Leaf' were similarly harvested and transported to the Hillsborough County Cooperative Extension Service office in Seffner. At both sites, jasmine was installed like turf grass sod. Slabs were lifted from a pallet and laid on the ground. Jasmine at both sites were overhead irrigated initially after installation.

Slab production of Asiatic jasmine was of limited success. The slabs produced did not have sufficient interweaving roots to firmly hold the slab together. During slicing of the15 ft long beds, unacceptably high percentages of shoots and roots were lost. As a result, the slabs were not the intact 1 ft x 2 ft sections sought. Slabs of the 1.5 plants/ft2 density and those in the Sand growing substrate were the worst. The best slabs were those grown in the Bark substrate at the 2.0 plants/ft2 density. Because the slabs were not intact, installation was slow and installed square footage was reduced to two-thirds that of the original bed area harvested. These characteristics were consistent across cultivars and installation sites.

Asiatic jasmine ground cover planted in raised beds at the MREC container production facility. The beds will be cut into slabs and installed arond a model home in the Tampa area in late 2001.
 
Phase 2   refers to the evaluation of these slabs once they are installed in a model home landscape.

Beginning about six weeks after installation builders, realtors, and visitors from the general public to the model home at Eagle Ridge, completed a survey querying them of their opinions of the jasmine beds. The majority of the respondents viewed the jasmine installation favorably. Building professionals most often cited greater aesthetic and more favorable economic considerations (lower irrigation and chemical inputs) for the jasmine beds compared to turf grass areas. In contrast, a simple majority of the general public thought the jasmine beds were less aesthetically pleasing than turf grass lawns. However about two-thirds of the general public respondents cited lower long-term maintenance of jasmine areas as reason to prefer it as an alternative to an entire turf grass lawn.

In conclusion, there are sufficient benefits, such as lower landscape water and pesticide applications, and interest from building professionals and general public, to justify continuing the pursuit of the goal of this project, i.e. to produce an easily installed jasmine slab that provides an "instant landscape" appearance after installation. On the production side, there are several important, but less critical, problems that should be solved relatively easily through further research. Critical problems stemmed from the loss of shoot and root mass with harvest. These losses magnified weak binding of a growing substrate by roots, and greatly diminished the quality and appearance of canopies. Possible solutions have been formulated and described. On the landscape side, information is entirely lacking as to how much and how long jasmine slabs should be overhead irrigated to achieve establishment.

The success of this project clearly rests on the response of the public. Asiatic jasmine cultivars are proven performers in Florida landscapes. We are quite confident that they can be grown in slabs, and in the future may possibly be produced in fields like turfgrass. Whether the public demand will be high enough for the industry to embrace this new production method is the key question we hope to answer with this study. The cost of ground cover slabs relative to turf, and future limits on residential landscape irrigation will also likely influence the ground cover's acceptance by the public.

 

Phase 3  Developing estimates of time and costs for production of harvestable slabs of Asiatic Jasmine 'Minima' in standard common nursery production trays based on liner density and root pruning treatments.   

In phase 3 of our project, we produced jasmine slabs grown in common nursery production trays.  Our objectives were to 1)determine the relationship between the number of liners per trays and the time to produce a harvestable slab, 2) determine the ability of air pruning versus copper impregnated cloth to limit root growth outside the bottom of the tray, and 3) develop estimates of the cost per slab for production of harvestable slabs based on liner density and root pruning treatment.   

Standard nursery production trays (10X20inch) were filled with a 70:30:10 Pine bark: Fl peat: sand substrate amended with dolomite limestone and micro-nutrients.  Three inch liners of jasmine were transplanted into each tray at densities of 2,3, or 4 liners per tray

Half of the trays were placed on Texel propagation fabric, which is impregnated with copper hydroxide to inhibit root growth, and the other half were elevated on a 2x4 treated lumber frame to allow for air-pruning.   Each tray received about 3 oz per liner of a 350ppm liquid fertilizer 20-10-20 and a broadcast application of Ornamental Herbicide II within a week after transplanting.  Polyon, a 9 month fertilizer was also applied the first week.  Routinely they were maintained by hand weeding or applying RoundUp original (without surfactant) at a rate of 1oz/gal.  They were irrigated daily  by overhead sprinklers with .20" initially for the first 2 months , then increased to 0.25" thereafter.  Root integrity, or 'knitting'  was evaluated qualitatively at 24, 30, & 36 weeks of production.