Plant diversity. Soil biology. Increased soil organic matter. These topics are at the forefront of minds of growers and agronomists around the world today. There’s a reason 2015 is the International Year of Soils.
But often when people think of these issues, it’s in the context of farmland, rangeland, or prairies – not the coastline. But the coast environment and maritime ecosystems can be equally well served by thinking about those factors.
That was one of the messages conveyed by Chris Miller, Manager of the Cape May Plant Materials Center (PMC) in New Jersey, in a recent online presentation. For growers and nursery operators located in coastal areas, the renewed attention to coastal plant complexes – which in the mid-Atlantic have risen in recent years particularly in response to the devastation wreaked by Hurricane Sandy – means opportunities to develop and market new products.
“The whole idea is to have a higher level of plant diversity,” said Miller, “rather than a monoculture.” Conservation plants are often thought in the context of coastal restoration projects (after events like Hurricane Sandy). But such crops can have other purposes, too.
American beachgrass, probably the most commonly known early succession coastal grass in the mid-Atlantic, is also used, Miller said, “inland on mine sites to jumpstart succession,” as well as on granatic soils along highways in New England to help control sand from spreading across the roads.
The plants can also be used in water quality applications, in agroforestry as windbreaks and buffers, as well as possibly in bioengineering and biofuels. Many of the plants are suited for the sandy, low-nutrient soils of the coastal plain as well as in coastal dunes. Some species, like the beach plum, can even be grown for value-added products such as wine and preserves.
What’s more, growing coastal conservation plants can bring diversity to your business. American beach grass is one of the best known coastal restoration plants. The Cape cultivar was the first plant released by the Cape May PMC, in 1972. It is grown successfully by a number of nurseries from North Carolina to New England.
The grass is a pioneer plant and does best where there is moving sand. On the dune, the plant is perennial, but in production it’s managed as an annual – undercut, divided and replanted every year – to maintain vigor. When the plant grows longer than a year or two without the disturbances found on the primary zone of a dune (without moving sand) the stems in the middle of the plant start to die.
The Cape May PMC was established 50 years ago, after the Great Nor’easter of 1962, which in its effects was similar to Hurricane Sandy. Both storms were more devastating for their flooding rather than high winds and both caused a considerable amount of damage. The 1962 storm crashed the land with 40-foot offshore waves, significant coastal erosion and a 42-inch snowfall in some places.
In the aftermath of both storms research showed the value of well-established, well-vegetated dunes. After Hurricane Sandy, scientists are pushing for wider selection and commercial production of distinct ecotypes as well as the development and use of a broader number of coastal plant species. In both cases, the goal is to develop plants and strategies that can stabilize the coastal dunes stretching along the Atlantic coast. That means opportunities for nurseries willing to grow these plants.
Dunes are important because they protect inland development from storms, flooding and erosion. They also act as a sand trap and sand reservoir as well as provide habitat for a variety of plant and animal species. Miller cited research that showed that in New Jersey dunes and coastal beaches are most the valuable ecosystems in the state on a per-acre basis. Dunes typically exhibit zonation. The primary zone is closest to the water, the secondary zone further back and will have a scattering of shrubs, and the tertiary zone, if it exists, is where you may find a maritime forest. “Each plant species has a niche in a particular zone,” Miller said.
For some years after the Nor’easter of 1962, beach grass, mainly Cape but also some Bogue produced in North Carolina, was used as the primary restoration plant – even in zones where it was ill-adapted, such as the zones farther back from the waterfront.
In a natural system, Miller said, “Beachgrass has most of its vigor and most of its growth on the frontal dune area where the sand is accumulating,” In the back dune area, it will likely be a small component of the plant inventory.
That means for coastal planting projects, there’s room for a variety of species, such as those typically found in nature in the different zones of a dune. For example, in the back dune area you often find species such as bayberry, coastal little bluestem, and saltmeadow cordgrass.
Beachgrass, Miller said, “is not the be-all and end-all of dune stabilization. It has its purpose, its function, as a pioneer plant.” In areas with a stable sand structure it can provide initial cover but it’s not going to “thrive long-term. You need other species in there to provide longer-term stabilization and cover.”
Since Sandy, there has been a shortage of beachgrass supply. That has led researches to look at other species that can survive in the primary zone of a dune. Some options include bitter panicgrass, sea oats (testing is underway to find a cold-tolerant strain of this plant typically found in warmer climes) and saltmeadow cordgrass, which, though associated with marsh environments, “performs very well on the crest and back side” of frontal dunes.
In addition to those grasses, forbs and wildflowers can provide dune strengthening while also adding diversity, creating a “sustainable plant system.” Suitable legumes include partridge pea, beach pea, trailing wild bean, to name just a few. In systems with a broad enough dune to accommodate woody species, bayberry, eastern red cedar, dwarf sumac, and beach plum are just some of a number of good options.
If you’re interested in adding any of these types of plants to your nursery mix, check with your local extension agent or contact the Cape May PMC for more information.