Spring-Cleaning in the Nursery

While we do not exactly have a spring season in south Florida, I use the common phrase “spring-cleaning” to denote this particular activity. I initiated an effort to clean out some of the weedy and invasive species that we have growing in our nursery and shade house. We have very limited nursery space to grow seedlings, cuttings and pups from some of our collections, therefore space is at a premium. Last month we obtained new plant specimens from nearby Fairchild Tropical Botanic Garden and last week we received several new arrivals from Montgomery Botanical Center. While we finalize garden planning on where to place these specimens, they may wait in the nursery area for several weeks before being out-planted. By cleaning out the nursery and taking stock of what we have, we can make space for new arrivals, focus on keeping plants healthy, and most importantly, remove invasive species.

I realized that we had several plants that are considered invasive species in south Florida and the Keys, while doing an inventory of our nursery stock. This issue is important to me since I have worked on the land management side of botany and seen what havoc invasive species can wreck on the environment, not to mention the hours spent removing the pests and the amount of tax-payer dollars spent trying, in vain, to control these weeds. While oftentimes these plants are beautiful, if they make it out of gardens and into our natural areas, they become invasive and threaten our native, south Florida species, many of which are already rare. Our Gardens are about 0.5 miles from the nearest natural area to which birds could potentially spread seeds. By having these plant species in our Gardens, visitors may be inspired by their beauty and possibly plant them at their homes, spreading the problem further afield. I would like to inspire people to plant native plants and non-invasive exotic plants. By eliminating the potentially invasive species from our Gardens, we can rest assured.

Among the plants we have removed from our nursery so far are wart fern (Microsorum scolopendrium) and Asian sword fern (Nephrolepis brownii), tropical almond tree (Terminalia catappa), Mexican fan palm (Washingtonia robusta), and cardboard palm (Zamia furfuracea – a cycad). We have begun removing fountain and napier grasses (Pennisetum setaceum/ P. purpureum) from our landscape and are replacing them with native grasses. There are a few specimens of other invasive exotics in the Gardens that we are grappling with: strawberry tree in our fruit garden (Muntingia calabura), arrowhead vine (Syngonium angustatum) climbing up a palm trunk, Governor’s plum (Flacourtia indica) & Brazilian pepper (Schinus terebinthifolius) providing privacy along a property line and actually rooted on the adjacent property, and foundation plantings of Queensland umbrella tree (Schefflera actinophylla) that provide shade and block road noise for guests and have been on the property for over 20 years.

Removing plants from the nursery is one thing, but how do we deal with these mature plants in the ground? To remove a Schefflera is a huge task with a high price tag, and with nothing large enough to fill its place, would leave a gaping hole. When is having a specimen that you can educate the public with more beneficial than removing it? These are some of the tough decisions that botanic gardens must make when potentially invasive species are part of our collections.

Cardboard palm (Zamia furfuracea) ready to be composted. This species has been added to the Florida Keys list of invasive plants due to its tendency to spread from the landscape into natural areas by seed dispersal. It pops up all over our Gardens from existing plantings which we are working on replacing.

A Tropical almond (Terminalia catappa) sapling on its way out. Seedlings of this species pop up throughout the Gardens even though the mature tree was cut down years ago. New seeds may arrive in mulch deliveries, as well.

Wart fern (Microsorum scolopendrium) that has escaped its nursery pot and started to grow along the ground. Watchful botanists in Miami Dade county are adding this plant to the state invasive species list as it is showing up in natural areas. It is not yet invasive in the Keys, and in fact may not become invasive down here since we have a drier climate, but we have many visitors from the metro Miami area and do not want to encourage them to plant this fern.

Asian sword fern (Nephrolepis brownii) specimen. This species is listed as invasive for Central and South Florida and is invading hammocks in the FL Keys. It is also invading nearby pots in the orchid house (see photo below). Ferns can be particularly tricky due to the multitude of spores they release. The Old World climbing fern and Japanese climbing fern (Lygodium microphyllum, L. japonicum) are both major problems in Florida and in several other southeastern states. Since its introduction in the 1960s, Old World climbing fern now covers 50,000 acres of habitat in Florida, literally climbing over every other plant in its path.  

Small sporophyte of Asian sword fern growing in adjacent pots.

On the flip side, botanic gardens may be some of the first places that a new species’ invasive potential becomes known, or a new pest becomes evident. It is then our obligation to spread the word and inform the local extension service and regulatory committees of the threat. Having staff members that are part of a local invasive plant watch group is helpful to stay abreast of developing issues in your surrounding area. It is our duty as botanical gardens to educate the public about these issues and promote the sale and use of local native plants and non-invasive exotic plants.

In the Florida Keys, our local eradication network is called the Florida Keys Invasive Exotics Task Force. This group includes local, state, and federal agencies and non-profit and public utility personnel who are responsible for removing invasive plants from local natural areas like state and county parks. By working with this group and others like it in south Florida (Everglades Cooperative Invasive Species Management Area & Florida Exotic Pest Plant Council) I am able to stay informed and help prevent the spread of invasive exotic species. Publications such as the AlterNatives Plant Guide are a great way to share local knowledge on landscaping and gardening with the public. 

Emily B. Magnaghi

Associate Director

Plant Immigration and Naturalization

Coconut palm at Kona Kai

Nothing exclaims "tropical paradise" more than the coconut palm. They are so common in our landscape in south Florida that they seem to be native to our region, but alas they are not. Where exactly does the coconut palm come from and how did it get here?

Historic records on the introduction of Cocos nucifera, the coconut palm, are difficult to trace since humans have been carrying this portable source of nutrition throughout the tropics for thousands of years. Coconut DNA analysis has shown that two varieties originated in Asia, one in the South Pacific and one in the Indian Ocean region. As far as when the coconut arrived in Florida, I located two articles. One recounted a tale of coconuts from a shipwreck floating up along the Palm Beach coast in the 1800s and another indicated the presence of coconuts in the Florida Keys in the mid-1800s. DNA analysis of Cocos nucifera which, combined with historic shipping records, show that the Indian Ocean variety of coconuts were brought to Africa by Portuguese sailors; this variety was then brought to the Caribbean. Either way, they have been here for over a hundred years and have made themselves right at home.

Coconut palm at Kona Kai

The coconut is one of the most useful plants for humans, especially due to its portability for travel on sea voyages. They have nutritious water and fleshy meat which is also processed into milk and oil, the oil is used for cooking and in cosmetics and soaps; building materials are obtained from the husks, leaves and trunk; the coir on the outside of the fruit has many traditional and commercial uses, also coconut husks are used culturally for decoration, and on and on. Early farming records in the Florida Keys indicate there were plantations of coconut trees, pineapples, tomatoes and other hardier vegetables. It was, and is, a valuable crop. It is also a valuable botanical teaching tool as people readily recognize and enjoy coconuts and are interested in learning about their various attributes. However, the coconut is not a native plant to Florida and has naturalized in the Florida Keys to the extent that it is now on the Keys' invasive species watch list.

Coccothrinax argentata, Silver palm, at Lighthouse Beach,
Eleuthera Bahamas

Close-up of Silver palm's silvery leaf

The coconut has become a problem locally at two popular tourist destinations, Bahia Honda State Beach and Lignumvitae Key Botanical State Park. Coconuts are washing up on the beach dunes at Bahia Honda and becoming established, potentially outcompeting the native Silver Palm, Coccothrinax argentata. Coconut palms persist in the tropical hardwood hammock at Lignumvitae Key, where they were planted early in the last century by private landowners, and their thatch and debris is inhibiting the germination of native plants. Left unchecked, coconut palms become established in the ecosystem and may alter the ecology for the remaining native plants and animals. In the photo from Lighthouse Beach on Eleuthera, Bahamas to the right, there are numerous coconut palms in the distance, their canopies popping up out of the native scrub. We are not sure what their long-term impacts will be, but state and county land managers in the Keys are not taking any chances. They are on the lookout for newly sprouting coconuts and actively removing trees, but they have their hands full with other, more invasive, species that are a bigger threat to the habitats in the Keys, so they need our help.

Coconut trimming at Kona Kai

How can we help reduce the number of coconuts in the environment? We need to ramp up our collection efforts and harvest them! I'm not kidding! If you have coconut palms on your property, you likely have someone come cut down the coconuts so they don't endanger pedestrians and property when they fall. Keep up the good work!
These delicious fruits also provide many cottage-industry product ideas to local artisans: homemade Keys coconut soaps, body scrubs, lotions and hair oils; locally sourced coconut milk for cocktails and coconut pies - who says we can only be famous for Key Lime pie?; cooking oil for fried lionfish fritters - another invasive species that we are hunting and eating! We need to jump on the locavore band wagon and start providing tourists with locally grown food and locally sourced ingredients so their experience in the Keys is even more memorable. 

Raw coconuts and two clever uses for cleaned/dried coconuts 

By actually using this valuable resource, we can help remove the coconuts from the environment, limiting their ability to disperse and grow in the wild. There are so many coconut palms throughout the state that it is inconceivable to think about removing them all so we need to come up with other means of control. I'm going to start by cutting the coconuts down from the tree in my front yard. I can't think of a tastier way to control invasive plants!

For more information on the genetic research done to decode the origins of coconuts, follow this link: 

Deep history of coconuts decoded: Origins of cultivation, ancient trade routes, and colonization of the Americas http://www.sciencedaily.com/releases/2011/06/110624142037.htm

Thanks for reading!
Emily B. Magnaghi
Associate Director