UF/IFAS Okeechobee County Extension Service
458 Highway 98 North
Okeechobee, FL 34972-2578
Phone: (863) 763-6469
E- mail: firstname.lastname@example.org
April 26, 2006
Feature Article - for release the week of April 30, 2006
Dan Culbert - Extension Horticulture Agent
Boston Fern or Sword Fern?
One of the ferns growing in our area is the Boston Fern. Because of its common name, newcomers are at first surprised to learn it is a Florida native. Long term residents will be equally amazed to learn that there is a look-alike species is often confused with this native plant. And, one exotic cousin of these frilly plants is an invasive weed, and is becoming a problem in our natural areas.
Today’s column will discuss how you can use Boston Fern in Florida Yard, and will help you to tell the good guy from the bad guy. Information for this article comes from our University of Florida Extension specialists the Florida Department of Agriculture.
Have you ever tried to get grass to grow under shady trees? Healthy turf grass in shady areas is not often challenged by a lack of water, fertilizer, or pests. While some turf is tolerant of lower light, none can grow well in shade. Instead, the right plant for this place is one that thrives in lower light conditions.
Boston Fern can be planted in clumps under the darkest canopy of a tree. When placed two to three feet apart, it spreads and fills in, quickly forming a two foot tall ground cover. Later on, fern beds may need thinning to encourage new growth. Shady spots are often moist, and the Boston Fern can tolerate occasional wet feet. Frosts will kill this plant to the ground, but it will regrow from the rhizomes remaining in the soil.
There are few serious pest problems with this landscape plant. Among those pests to be on the lookout for are scales, mealybugs and mites. Under wet conditions, snails, slugs and fungal diseases can bother Boston Fern.
A nice place to use Boston ferns is in the base of palm fronds, called boots, where they grow as epiphytes. Palms that are often seen with these ferns covering their trunks include Date Palms, Pindo Palms, and Cabbage palms - our state tree. When growing in this manner, they are only taking up space and do not harm the palm. Their water and nutrients needs are not taken from the palm.
Boston Fern is a native groundcover plant in moist shady areas of southern Florida. Photo: Dan Culbert
Boston Ferns do well as hanging baskets or in indoor containers. Photo: Purdue University
There are hundreds of different varieties of Boston Fern available from nursery growers. Some common cultivars include “Fluffy Ruffles”, “Roosveltii” and “Whitmanii”. Boston Ferns can also be used in containers and in hanging baskets. “Bostoniensis” is a very common cultivar. Found near Boston in the 1890s, it became a fixture of the overstuffed parlors of the time. It is grown by Florida nurseries and shipped to northern markets for indoor use. If you need information on how to grow this as a house plant, call our Master Gardeners for details.
Native or Exotic?
Ferns don’t grow flowers - they produce clusters of dust-like spores under their fronds. Using a hand lens, look for a small plate that covers the bumps. Part of the botanical name refers to the kidney-shaped covering on these spore cases.
Five species of these ferns have been identified in Florida’s natural areas, but only two are natives. The differences between these plants are in the hairiness of the leaves, the shape of the spore covering, and the size and color of scales growing on the stem (rachis) of the fronds. Another key feature is the absence or presence of fleshy underground tubers.
The most abundant native (Nephrolepis exaltata) is found growing from Lake County south through the Florida peninsula. The other Florida native species (N. biserrata) grows naturally in Highlands, but not in Okeechobee County. Three other species of Boston Fern have naturalized in Florida, plus a hybrid of our two native species.
Of special concern to natural land managers is the Erect or Tuberous Sword Fern (N. cordifolia). This non-native fern has escaped from cultivation and grows in most of Florida and even into Georgia. It can spread aggressively in the landscape, forming dense stands that displace native ground covers. The Erect Sword Fern thrives in poor growing conditions with dense crowns of long, drooping leaves. Look for it in pine rocklands, flatwoods, marsh edges and hammocks.
Non-native Boston ferns can be distinguished from native species by two characteristics:
· Leaflets of the native Boston Fern do not overlap each other where sprout from the rachis or leaf stem; the leaflets of the Erect Sword Fern do overlap each other.
· Another feature is the presence of round fleshy underground tubers on the non-native fern; the native species do not produce these structures.
The leaflets of non-native Sword ferns overlap. Note that the leaf spots are spore cases. Photo: Jeff Hutchinson, Archibald Biological Station.
Invasive Sword Ferns have these tuberous storage structures; don't let them loose! Photo: Jeff Hutchinson, Archibald Biological Station.
Please be careful when purchasing these ferns if they will be used in the landscape – they may spread into wild areas. Be cautious when disposing of yard waste - there are better ways than to dumping this material on the roadside or in an undeveloped areas. Do your part to preserve and protect our natural heritage by inspecting the roots of your new fern to see if the tubers are present. Make a conscious choice to keep your Florida Yard a more natural place to enjoy our beautiful piece or paradise.
I’ve placed more information on our Okeechobee web page, http://okeechobee.ifas.ufl.edu. If you need additional information on these ferns, please email us at email@example.com or call us at 863-763-6469. Local residents can stop by our office at 458 Hwy 98 North in Okeechobee, and visit our Okeechobee County Master Gardeners from 1 to 5 PM on Tuesday afternoons.
Trade names, where used, are given for the purpose of providing specific information. They do not constitute an endorsement or guarantee of products named, nor does it imply criticism of products not named. The Florida Cooperative Extension Service - Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information, and other services to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin. Florida Cooperative Extension Service / IFAS / University of Florida. Larry A. Arrington, Dean Last update: 05/04/2006 . This page is maintained by Dan Culbert
Notes from Ken Langeland, 4/27/06: I've eliminated N. cordifolia from my yard here in Gainesville except for battling it at the property line (along with English ivy, Chinese wisteria, golden rain, camphor, etc.). I've planted both N. exaltata and N. biseratta in the yard (both are wild types). N. exaltata is really much more attractive than N. cordifolia; and, as a ground cover, I think it spreads as fast and fills in as well as N. cordifolia. N. exaltata also seems to be, at least, as cold tolerant as N. cordifolia.
N. biserrata is interesting as a specimen but doesn't fill in, seems to be less cold tolerant, and seems to come back very slowly after a winter when it gets knocked back.
Langeland, K. A. Natural Area Weeds: Distinguishing Native and Non-Native "Boston Ferns" and "Sword Ferns" (Nephrolepis spp.) [SS-AGR-22]. Gainesville: Florida Cooperative Extension Service, 3/05. http://edis.ifas.ufl.edu/AG120
Wunderlin, Richard. Atlas of Florida Vascular Plants. Tampa: University of South Florida, 2006. Insert "Nephrolepis" in the search box to see these species of Florida ferns: http://www.plantatlas.usf.edu/result.asp