Mangroves are among the most recognizable American trees. You’ve probably seen photos of mangrove trees growing on stilt-like roots in swamps or wetlands in the South. Still, you’ll find out some amazing new things if you involve yourself in mangrove seed propagation. If you’re interested in growing mangrove trees, read on for tips on the germination of mangrove seeds.
Growing Mangrove Trees at Home
You’ll find mangrove trees in the wild in shallow, brackish waters of the southern United States. They also grow in riverbeds and wetlands. You can start growing mangrove trees in your backyard if you live in USDA plant hardiness zones 9 through 12. If you want an impressive potted plant, consider growing mangroves from seed in containers at home.
You’ll have to pick between three different types of mangroves:
- Red mangrove (Rhizophora mangle)
- Black mangrove (Avicennia germinans)
- White mangrove (Laguncularia racemosa)
All three grow well as container plants.
Germination of Mangrove Seeds
If you want to start growing mangroves from seeds, you’ll find that mangroves have one of the most unique reproductive systems in the natural world. Mangroves are like mammals in that they bring forth live young. That is, most flowering plants produce dormant resting seeds. The seeds fall to the ground and, after a time, start to germinate.
Mangroves do not proceed in this manner when it comes to mangrove seed propagation. Instead, these unusual trees start growing mangroves from seeds while the seeds are still attached to the parent. The tree can hold onto seedlings until they grow almost a foot (31 cm.) long, a process called viviparity.
What happens next in the germination of mangrove seeds? The seedlings may drop off the tree, float in the water the parent tree is growing in, and finally settle and root in the mud. Alternatively, they can be picked from the parent tree and planted.
How to Grow a Mangrove with Seed
Note: Before you take mangrove seeds or seedlings from the wild, be sure that you have the legal right to do so. If you don’t know, ask.
If you want to start growing mangroves from seeds, first soak the seeds for 24 hours in tap water. After that, fill a container without drain holes with a mixture of one part sand to one part potting soil.
Fill the pot with seawater or rainwater to one inch (2.5 cm.) above the surface of the soil. Then press a seed into the center of the pot. Position the seed ½ inch (1 cm.) below the soil surface.
You can water mangrove seedlings with fresh water. However, once a week, water them with salt water. Ideally, get your salt water from the sea. If this is not practical, mix up 2 teaspoons (10 ml.) of salt in a quart (1 L.) of water. Keep the soil wet at all times while the plant is growing.