Salt Tolerant Plantings

Rising water levels, freak winter storms, hurricanes and coastal flooding have all been common occurrences here in southern New England over the past two years. What used to be a relatively protected coastline unaffected by major storms, Connecticut has recently been battered on a regular basis by these once in a century storms. The landscapes along the coast from New Jersey to Maine have been inundated with sea water and many residential landscapes have been killed off by the floods of salt water. Have you considered the salt tolerance of the plants in your garden?

Those residing in Coastal Connecticut as well as other homeowners up and down the Eastern seashore have been challenged by the impact of salt on their coastal landscapes. Salt impacts plants in the form of salt spray from winds or accumulation of salt in the soils from inundation during periods of flooding or high tides. Brackish or salt water and even de-icing salt can pose a risk to many landscapes. In some area salt is only a few feet down at the water table. Why is salt bad for plants? First salt causes plants to lose water, secondly salt interferes with the absorption of nutrients so that the plant will become deficient and lastly it interferes with the plant's metabolism making the plant less efficient and less productive in the uptake of water and nutrients necessary for growth.

Many people have landscapes filled with plantings that are not salt tolerant and fear losing their entire landscape when storms hit. There are ways to salvage some of your favorite plants if you've been flooded. Perennials can be dug up and the roots rinsed and replanted in fresh soil. This is not an option for trees and shrubs. The best way to salvage these plantings after being exposed to or covered in salt water is to flush the soil out completely by using fresh water. There is no guarantee this will work but is better than doing nothing at all. So turn on your irrigation system and let it run or water thoroughly with a hose. Also try to rinse off foliage that has been contaminated with salt spray.

If you intend on installing plants that are not tolerant of salty soils, you will need to plan to remove any soil inundated with salt water and install new topsoil down to a depth of 12-18" before planting. It is usually recommended to amend the typical coastal soils with plenty of compost to increase the water holding capacity, since these soils tend to be very sandy. It is recommended that you take a soil pH test to check the levels and add specific amendments to adjust it to optimum levels to improve the landscape plantings ability to absorb mineral nutrients.

It is recommended to use native plantings that are local and adapted to your coastal environment. Changes in taste and environmental awareness have brought about the focus on using more native plants rather than non-native or exotic plants for landscapes.

Top ten reasons to use native plants in your landscape:

1. Once Established, Native Plants Require Little Care and Maintenance
2. Native Plants Save Money on Landscaping Cost
3. Native Plants Are Pest and Disease Resistant
4. Once Established, Native Plants Require little or no Watering
5. Once Established, Native Plants Require No Fertilization (Or Pesticides)
6. Native Plants Survive Harsh Winters and Hot Dry Summers
7. Native Plants Provide Wildlife with Food and Protection
8. Native Plants Help Reduce Erosion To a Minimum (Good For Shorelines)
9. Native Plants Are Non-Invasive
10. Native Plants Look Like They Belong in the Landscape (Gets Us In Touch With Our Surroundings)

Native plants when used in the landscape provide ecological benefits to local wildlife while also requiring less maintenance by property owners, since the plants are more adapted to the local climate and soil conditions. Most native plants require little or no irrigation or fertilizer to thrive. They are normally more resistant to local insect pests and diseases so in the long-term cost less to maintain.

Native shrubs that will grow along Long Island Sound and can be planted in a sandy dune or just above high tide line are Beach Plum (Prunus maritima) and Northern Marsh Elder (Iva frutescens). They can handle occasional inundations and salt spray besides having lovely flowers and ornamental fruits. Further away from the high tide line other native shrubs that have ornamental value, which are both tolerant of salt spray and salty soils, include Coastal sweet pepperbush (Clethra alnifolia), Sweet fern (Comptonia peregrine), Common winterberry (Ilex verticillata), Carolina rose (Rosa Carolina), Highbush blueberry (Vaccinium corymbosum), Southern arrowwood (Viburnum dentatum) and Staghorn sumac (Rhus typhina).

Some non-native ornamental shrubs that are tolerant of salt spray and found commonly in seaside plantings include Hydrangeas, Rose-of-Sharon, Rugosa roses, Butterfly bush, Bayberry, Potentilla, Weigelia and Pyracantha.

Native trees that have ornamental value and are tolerant of both salt spray and salty soils include Allegheny serviceberry (Amelanchier laevis) and American Holly (Ilex opaca). Some larger shade trees that are also tolerant of both salt spray and salty soils include White oak (Quercus alba), Post oak (Quercus stellate), and Sassafras (Sassafras albidum). More common are the native trees that are tolerant of salt spray but are intolerant of salty soils, these include Pagoda dogwood (Cornus alternifolia), Cockspur hawthorn (Crataegus crusigalli), Eastern red cedar (Juniperus virginiana), Pitch pine (Pinus rigida) and Sycamore (Platanus occidentalis). You could plant these trees on property that is near to the seashore but is high enough to never be flooded.

Some non-native trees that are tolerant of salt spray and found commonly on seaside properties include Crabapple, Little Leaf Linden, Stone Pine, Black Pine, Mugo Pine, Blue Spruce, Paperbark Maple and Honey Locust.

Some of the best native grasses that can be used for seaside plantings are American Beach Grass (Amnophila breviligulata), Big Bluestem (Andropogon gerardii), and Switchgrass (Panicum virgatum). Some of the top non-native grasses that are tolerant of seaside conditions and that are found commonly in seaside plantings include Fescue grass and Fountain grass.

Some of the best native perennials that can be used for seaside plantings are Sea lavender (Limonium carolinianum), Seaside goldenrod (Solidago sempervirens), Perennial saltmarsh aster (Symphyotrichum tennifolium), Beach Heather (Hudsonia tomentosa) and Beach pea (Lathyrus japonicus var. maritimus).

Gardening near the coast and along the water has a unique set of challenges not found in other environments. For a successful and attractive coastal garden that will survive the worst mother nature has to throw at it, start with planting the right plants.

Landscape Architects can help you plan and design a garden near the coast. Not sure where to begin planning your coastal landscape? Rock Spring Design Group, LLC, Landscape Architects, Site Planners and Sustainable Designers can help you. Give us a call at 203.268.6979begin_of_the_skype_highlighting 203.268.6979 FREE end_of_the_skype_highlighting or email us at info@rockspringdesign.com to set up a free one hour consultation to discuss your upcoming landscape project.

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