March 18, 2013 03:46

Choosing the Right Seed

It all starts with a seed. Before a plant rises up, a seed has to be planted. Choosing the right seed for any project is so important, because it sets the tone for the finished product.

That beautiful lush green lawn that you see from your window didn’t just happen. It, too, had a beginning, a seed. A combination of factors went into achieving those results.

When choosing the proper seed, one must take into consideration how the area will be used. In addition to your choice of seed, the soil type must also be taken into account—pH levels, shade and sun exposure. How much maintenance will it require? Is erosion control a primary concern?

The quality of products you choose to apply is also important. Nowhere do these variables come into play more than with seed. Excellent results come from using the highest quality seed in the best mix for the application.

All of these questions, plus more, must be factored into choosing the proper seed for a particular site. Poor, substandard seed choice leads to disastrous results. The wrong variety will result in an expensive redo of a project, adding unnecessary cost to your bottom line. Doing it right the first time should be a guiding principle.

So, how do you pick the right seed? We turned to some professionals who deal with this question all the time—the Departments of Transportation (DOTs). We contacted DOT landscape architects in Texas, Georgia, and New york, to get some insight into the way they select seed.

Just the sheer volume and variety of seed that a landscape architect working for a DOT has to deal with can be overwhelming. They ask many questions and get soil samples of the given areas before even one single seed is purchased. Their step-by-step pro-cess is helpful for any landscape architect or contractor deciding on seed varieties, blends and mixes.

As you can imagine, each DOT has a different approach, based on the needs in their state. Within each state, there is such a diversity of ecologies, climates and topography that no one seed is used exclusively. So, how do they go about covering massive amounts of land with the proper seed?

All three of the landscape architects we spoke with start with simple questions. What are the goals for each project? What do they want to achieve on a particular project? Is the land being prepared for aesthetic value, or just being prepared to control erosion? How can specific plants, flowers, grasses, forbs, legumes, annuals, perennials, trees and shrubs affect the project’s goal? Is soil erosion of specific interest? All of these questions help the erosion control professional decide what seed will be planted for a particular site.

More states are putting a stronger emphasis on the beautification of their projects. Many grasses, plants and forbs are selected for their visual appeal. They may be planted at different times of the year to suit a variety of seasonal needs.

Color is also considered in beautification projects. Wildflower species are of great interest to the public. The seed selection in this process reflects visual aesthetics over more practical concerns.

Another question that goes into the decision process include the location of the project. Does the location receive a large amount of sunlight, or sit entirely in shade? Are there transition zones? Is it a high traffic area? Is it near a school? Will children or other members of the public be trampling on it?

What type of region will the seed be planted in? Different plant material grows at different times of the year and does well in different regions. Planting seed that requires a lot of moisture in a dry desert environment will have an obvious outcome; the same is true for elevation and soil types. A rocky or sandy soil in the high mountains will need plant material that can survive in harsher environments. The climate zone of each location will determine the best type of seed to use. A warm weather seed will not be successful in a colder climate, and vice versa.

Each region of the United States has a diversity of wide-ranging ecologies. Regional offices within a state will differ in their requirements from area to area. However, some basic needs remain the same from region to region and from state to state. Stabilization and cover are essential to any reclamation or restoration project. Soil retention is paramount to maintaining natural plant life and grasses, as well as biodiversity.

Some state DOTs focus on environmental concerns from the getgo. Davie Biagi, landscape architect for the Georgia DOT, says, “We focus on environmental mitigation projects, historical mitigation projects and ornamental landscapes, where we want to do a more natural landscape.”

The DOTs also know seed selection is a project design issue. A designer who mixes seed will know the different requirements of both the project and the state standards. They have vast reference lists of seed from which to choose.

Nancy Alexander, landscape architect for the state of New york DOT, says her state usually allows contractors to select seed for jobs as long as it meets state specifications.

Peter Dunleavy, head of the Specifications Unit for the New york DOT and a former landscape architect, added that, “Our goal with our turf mixes is to reflect the basic industry standards, to get a basic, sustainable stand of turfgrass.”

In Georgia, they like to use their most recent specifications (GDOT 700 Grassing Specs) which includes native grasses and native herbaceous perennials and forbs. The mix is made from three species of native grasses and two species of herbaceous forbs. This mix goes on the natural landscape and disturbed areas, and provides a very successful and reliable cover for stabilizing with native species. A lot of the time, this is used in conjunction with large canopy native shade trees and native understory trees and shrubs, in order to create the multi-tropic landscape, as required by the state’s Environmental Protection Division.

A major concern for all three of the landscape architects interviewed for this article is the issue of seed that is native to the project site. All three would prefer to use more native seed. Using native seed makes sense because it’s going to do better over time. Why mimic what is already succeeding in nature?

Natives are usually more successful in the long run, but they typically take longer to establish. However, they will be adaptive to the water/moisture levels, the climate, the elevation and biodiversity, and will also be less expensive to produce and maintain. Exotic foreign seed that has to be harvested and shipped from a long way off will be more expensive and runs the risk of bringing non-native pests or disease with it.

“We really have seen a big push in expanding the native seed market,” said Dennis Markwardt, landscape architect for the Texas DOT.

“And one of the things that they’re really pushing—and it’s helping us—is not so much looking for forage production out of these plants, but for stabilization and the biodiversity that these plants provide.

In a lot of cases, the lower succession-type plants germinate and establish much easier than those that have traditionally been on the seed market.”

In Georgia, DOT landscape architects would like to go native as much as possible. But for roadside projects, where a clear zone exists, this is difficult. Clear zones require more vigorous seed that can stabilize the soil in less than fourteen days and can be mowed regularly. Native tree seedlings must be prevented from establishing in these zones.

This question will also be addressed by any landscape architect trying to settle on what their goals are with regard to a given project: Go native or stick with commercial blends?

Wildflowers

The State of Texas has been a pioneer in wildflower preservation and proliferation. Their native wildflowers bloom at different times of the year, and in a state as big as Texas, this can prove challenging. This is especially an issue when it comes to orchestrating their picturesque blooms with year-round needs of sometimes competing fauna and flora. In some places, grasses that are normally maintained along roadsides and highways are not mowed, to allow the native wildflowers a chance to set seed.

However, the use of wildflowers has its limitations. “Preservation and propagation of our native wildflowers has always been the utmost on our list,” says Markwardt. “But we’ve really had a limited amount of native grasses available that actually perform statewide.”

Other areas of concern to DOT landscape architects is how to create unique spaces that will control erosion, use native plant material, and preserve wildlife. If a wild hog or deer feeds on a specific kind of grass or clover, it’s probably not wise to use this seed along a highway project. A plant that brings an animal close to traffic can result in dangerous and costly collisions. Accidents could result in personal injury, damage to public and private property and potential lawsuits. And it certainly doesn’t preserve the wildlife.

These concerns, as well as issues of climate, microclimate, exposure, water needs, erosion prevention and stakeholder requirements all go into the seed selection process. So, now we’ve gotten a glimpse of what elements of the seed selection process are similar from state to state, and which are different. Longterm versus shorter-term needs and goals have to be addressed too. The use of commercially-blended mixes has to be weighed against the desire of a state to adhere to Conservation Reserve Program needs with native grass and plant seed. Historic, environmental and ornamental concerns all affect seed selection as well.

If a project is to be successful, whether in aesthetic terms or in a utilitarian sense, it all begins with the choice of seed. That’s the beginning.

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In many ways, we are fortunate that, in our chosen profession, we are able to help people when certain disasters occur: the tornadoes in Missouri, Oklahoma, Louisiana and Georgia, the flooding in Louisiana, the snows in the northeastern part of the country, the rain in California, and the snow in Colorado....

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