How to Grow Mangrove Trees
by Nick Hammond on Aug 28, 2022
*Please follow all local laws and regulations regarding obtaining, planting and trimming of mangroves
Mangrove trees are tropical trees that grow in brackish water along coastlines and estuaries. Often characterized by their elaborate root systems, mangroves play an important role in stabilizing shorelines and providing habitat for fish, crabs, birds and other wildlife. Growing mangrove trees can help protect coastal areas by reducing erosion from storms and floodwaters. With some planning and care, you can successfully grow mangrove trees to restore shoreline areas.
Choose a Suitable Location
Selecting the right location is key when planning a mangrove planting project. Mangrove trees thrive best in tropical and subtropical climates located between 25°N and 25°S latitude where temperatures stay above 60°F year-round. Coastal areas such as shorelines, bays, coves and rivers located within this climatic range provide ideal conditions. Specifically, look for a calm, shallow water area where sediment accumulates and tides ebb and flow regularly. Soft substrate containing mud, sand and clay allows mangrove roots to establish easily. The water must be brackish - a mix of freshwater and seawater with a salinity range of 10-25 ppt. Measure the water salinity over several seasons and different weather conditions to ensure it stays in the ideal brackish range before selecting a site.
Obtain Mangrove Seedlings
Mangrove forests contain different mangrove species suited for varying water depths and salinity. Common species used for shoreline restoration projects include red mangrove, black mangrove and white mangrove. Buttonwood trees are sometimes included as well. Mangrove seedlings can be purchased from reputable aquatic plant nurseries that harvest seeds from existing forests and propagate them sustainably. Select young mangrove plants that are 12-18 inches tall with healthy, green leaves and no signs of disease. The three main mangrove species have different optimal planting sizes:
- Red mangrove: 12-18 inches
- Black mangrove: 8-14 inches
- White mangrove: 6-12 inches
Request the appropriate species and sizes for your particular site and growing conditions. Plan to plant seedlings 1-2 feet apart so trees have sufficient space as they mature. Mangrove seedlings are sensitive to temperature and require shading, so time delivery to coincide with your scheduled planting date. Keep seedlings moist and cool until ready to be planted.
Plant the Seedlings
Once you obtain your mangrove seedlings, prepare to plant them at low tide when the site is exposed and not flooded. Measure the tidal fluctuations to determine the best time for planting. Dig holes or trenches in the sediment spaced 1-2 feet apart for each seedling. The holes should be wider than the seedling's roots to allow for future growth. Carefully place each mangrove plant into its hole and backfill sediment around the base. Plant seedlings at a depth so the bottom 2/3 of the stem is buried beneath the sediment. Only the top leaves should stick out above the surface. This allows the seedling to stand upright, establishes the roots and reduces stress. Complete all planting during the same low tide period to keep the seedlings moist.
Care for the Mangroves
Caring for newly planted mangroves will help ensure their survival and growth. Gently flushing the plants with tidal water is important. Allow tidal water to naturally flow through the site at high tide. You can also manually flush salt water over the seedlings using a hose twice a week. This mimics the tidal currents mangroves need. Check for invasive weeds and remove any debris that collects around the seedlings. Add a thin layer of fresh sediment each year around the base to encourage upward root growth. Place plastic guards around young seedlings to protect from predators. Monitor the plants regularly for signs of disease or stress. Extreme weather such as heatwaves or cold snaps can harm mangroves, so take measures to shield the site during unusual conditions until the trees mature.
With the right growing conditions, mangrove trees can reach 20 feet tall or more at maturity. Be patient, as it takes at least 5-10 years for planted mangroves to fully establish and longer to develop into a mature forest. But in time, your efforts will create an important new coastal habitat for wildlife and protect the shoreline from erosion. Enjoy watching your mangrove trees prosper.
When you purchase from MANG you join a movement of people who are banded together to protect, preserve and restore our ecosystems. The future depends upon stewards like you stepping up to the cause to protect our Earth today.
