North America Non-native Plant

Gray Mangrove

Botanical name: Avicennia marina var. resinifera

USDA symbol: AVMAR

Life cycle: perennial

Habit: shrub

Native status: Non-native, reproduces and persists in the wild in the lower 48 states  

Gray Mangrove: A Unique Coastal Plant for Specialized Gardens Meet the gray mangrove (Avicennia marina var. resinifera), a fascinating coastal plant that’s as unique as it is challenging to grow. This distinctive shrub brings a touch of tropical coastline to specialized garden settings, though it’s definitely not your average backyard ...

Gray Mangrove: A Unique Coastal Plant for Specialized Gardens

Meet the gray mangrove (Avicennia marina var. resinifera), a fascinating coastal plant that’s as unique as it is challenging to grow. This distinctive shrub brings a touch of tropical coastline to specialized garden settings, though it’s definitely not your average backyard plant!

What Is Gray Mangrove?

Gray mangrove is a perennial, multi-stemmed woody shrub that typically reaches 13 to 16 feet in height, though it can sometimes grow taller or remain single-stemmed depending on environmental conditions. What makes this plant truly special are its distinctive gray-green leaves and unique aerial root system called pneumatophores – specialized roots that stick up from the ground like tiny snorkels to help the plant breathe in waterlogged conditions.

Native Status and Distribution

Here’s where things get interesting: gray mangrove isn’t actually native to the United States. This hardy coastal plant originally hails from Australia, Southeast Asia, and the Indo-Pacific region. However, it has established itself in California, where it now reproduces spontaneously in the wild without human assistance.

Should You Plant Gray Mangrove?

The short answer? It depends on your specific situation and goals. Here are some factors to consider:

Reasons You Might Want to Plant It:

  • Exceptional salt tolerance makes it perfect for challenging coastal conditions
  • Unique aesthetic appeal with distinctive foliage and interesting root system
  • Excellent for erosion control along coastlines
  • Educational value for learning about mangrove ecosystems
  • Attracts pollinators with its small white flowers

Reasons You Might Want to Skip It:

  • Requires very specific growing conditions that most gardens can’t provide
  • Non-native status means it doesn’t support local ecosystems as well as native alternatives
  • Limited to USDA hardiness zones 9b-11 (very frost-sensitive)
  • Needs consistent high moisture and coastal conditions

Growing Gray Mangrove Successfully

If you’re determined to give gray mangrove a try, here’s what you need to know:

Growing Conditions:

  • Climate: USDA zones 9b-11 only – this plant cannot tolerate frost
  • Sunlight: Full sun exposure
  • Water: Consistently moist to wet conditions; thrives in brackish or salt water
  • Soil: Salt-tolerant; can handle high salinity levels that would kill most plants
  • Location: Coastal areas with access to salt spray and high humidity

Planting and Care Tips:

  • Choose a location with consistent moisture and good drainage
  • Ensure the planting site can accommodate the plant’s mature size of 13-16 feet
  • Provide protection from strong winds while establishing
  • Water regularly, especially during dry periods
  • No pruning required – let it grow naturally for best results

Consider Native Alternatives

Before committing to gray mangrove, consider these native California coastal plants that might better serve your garden and local wildlife:

  • California saltbush (Atriplex californica) – excellent salt tolerance
  • Coyote brush (Baccharis pilularis) – coastal shrub with wildlife benefits
  • Beach sagewort (Artemisia pycnocephala) – beautiful silver foliage
  • Seaside daisy (Erigeron glaucus) – colorful coastal groundcover

The Bottom Line

Gray mangrove is undeniably fascinating, but it’s a plant for very specific situations and dedicated gardeners. If you have the right coastal conditions and are passionate about unique plants, it can be a striking addition to specialized gardens. However, for most gardeners, native alternatives will provide better results with less fuss while supporting local ecosystems. Whatever you choose, make sure it’s the right fit for your garden’s conditions and your gardening goals!

Gray Mangrove

Classification

Group

Dicot

Kingdom

Plantae - Plants

Subkingdom

Tracheobionta - Vascular plants

Superdivision

Spermatophyta - Seed plants

Division

Magnoliophyta - Flowering plants

Subdivision
Class

Magnoliopsida - Dicotyledons

Subclass

Asteridae

Order

Lamiales

Family

Verbenaceae J. St.-Hil. - Verbena family

Genus

Avicennia L. - mangrove

Species

Avicennia marina (Forssk.) Vierh. - gray mangrove

Plant data source: USDA, NRCS 2025. The PLANTS Database. https://plants.usda.gov,. 2/25/2025. National Plant Data Team, Greensboro, NC USA