Since the use of wildflowers in landscape design is relatively new, many Landscape Architects are not familiar with the writing of specifications for wildflowers. Ben Lednicky, ASLA, Houston, is specifying wildflowers in his projects from South Texas to the, Bahamas.

“Wildflowers are not meant to replace traditional plant materials,” said Lednicky, “they are alternatives to be used in areas where intense color is needed at a cost that is compatible with what the client has budgeted for his project.”

“Wildflowers are another tool we have to use in the landscape that we didn’t have five years ago because we didn’t have the availability of seed, the availability of equipment to successfully plant the seed, nor the general knowledge of how to conduct a planting program which included wildflowers.”

“Every area seems to have its own peculiarities as to soil type and climatic conditions,” said Steffens. “In choosing and specifying our wildflower mixes we look at a number of things. We first check the natives that grow in the area and determine what seeds from those plants are available. We then have to look at cost and we have found that one of the essential elements in this facet of the plantings is something that few Landscape Architects are aware of and that is the difference in the sizes of the seed and the ratios needed to produce a dense palette of color.”

The examples Steffens uses are popular wildflowers in Texas, Bluebonnets and Indian Paintbrush. Bluebonnet seed are more plentiful and seed producers, such as Wildseed, Inc., raise there own seed from the plants that s grow wild in the Texas countryside. Indian Paintbrush seed, on the other hand, are very scarce and very expensive. However, seed mixtures which include the two usually consist of 25 pounds of Bluebonnet seed and only one quarter pound of Indian Paint Brush seed. Indian Paintbrush seeds are about one hundreth the size of the Bluebonnet seed. Scarlet Flax, the brilliant red wildflowers shown in one of the pictures accompanying this article, for example, is planted by the highway department at a rate of eight pounds per acre, whereas Bluebonnets are specified at 30 pounds per acre.

Wildflower planting specifications must be easily read and understood by all prospective bidders. Specifications will be broken down into the two major sections of materials and installation.

Always specify wildflower seeds by botanical names (Genus and Species) as well as the common name to prevent confusion. The material rates should be specified by the acre or per 1,000 square feet.

The two ways to specify wildflower seed rates are in bulk lbs. or PLS lbs. (pure live seed).

Pure live seed is figured by multiplying the germination percentage by the purity percentage then divide the total by 100. This will indicate the percentage of pure live seed in the bag.

Please note that the contractor must make this conversion to comply with a specification that requires planting seed on a PLS basis.

The contractor must determine the PLS for each species prior to purchasing seed in order to place an order for enough bulk lbs. of seed to complete the job.

A more simplified method of specifying rates of Wildflower seed is by bulk lbs. A Minimum Acceptable Germination Standard (MAGS) is assigned to each variety of seed with a blanket purity for all species.

• All seed must meet the requirements of the Texas Seed Law (Texas Department of Agriculture) including the testing and labeling for bulk seed.
• All seed shall have been tested by a certified seed laboratory with certified results presented to the Texas Highway Department Engineer in writing prior to planting.
• All seed shall be of the previous season’s crop and the analysis shown on the container shall be dated within seven months prior to planting date.
• All seed must be as labeled and free of noxious weeds. All seed is to at least 95% pure. Each certified seed analysis must be placed inside of the container and one secured to the outside of the container. The seed tags shall indicate the botanical name, common name, purity, germination and shall certify that the seed enclosed meets all requirements of the Texas Seed Law. The Texas Highway Department reserves the right to test samples of any seed.
• Each variety of seed supplied and delivered to the job site in separate containers. Any mixture of seed without the specific permission of the Texas Highway Department will be rejected.

Installation

It is the responsibility of the contractor to inspect all proposed seeding sites during the bid period. Access to all sites without damaging surrounding areas is the responsibility of the contractor.

Planting

The amount and type of seed planted per acre shall conform to the rates indicated in the Materials Section of the Specifications.

The planting method used shall ensure that the seed make direct, positive contact with the soil.

The method of seed installation shall be subject to the approval of the Landscape Architect. Hydro-seeding, Cultipack seeding, fertilizer spreader seeding or any other broadcast method is not acceptable and will not be permitted as a method of distribution unless approved by the Landscape Architect.

A drill-type seeder, specifically calibrated for each type of seed, is recommended for the installation. Such as J-Thom Wildseeder or an approved equal.

Each seed type must not be mixed with other types. Seed of like size and shape may be mixed at the job site for planting with the specific approval of the Landscape Architect.

The method of installation must be capable of planting seed in all areas shown on plans, including any sloping areas.

If a calibrated drill type seeder is used for seed installation, the contractor is to test for calibration of each seed dispenser (to the satisfaction of the Landscape Architect) prior to beginning installation