Indian River County Extension Service
1028 20th Pl, Suite D
Vero Beach, FL 32960
20 March 2002
FOR RELEASE : 24 March 2002
Daniel F. Culbert, County Extension Director
PALMS FOR ZONE 10
Often people ask our office for planting suggestions appropriate for local growing conditions. Cold hardiness is of major importance in making these recommendations. For the past ten years, the common wisdom was that our areaís winter temperatures would annually dip into the 20's. Recent temperature data may now indicate our local average minimums stay in the 30 degree range. For landscape enthusiasts, this means that "Zone 10" palms could be added to our Indian River area with a little more assurance that they will stick around a while longer.
Todayís Palm Sunday column will offer my suggestions for some zone ten palms that would work well in our Florida Yards, and offers some ideas on why others species of these tropicals might be avoided. Information for todayís column comes from the National Arbor Day Foundation, local palm enthusiast Dr. John Kennedy and University of Florida Extension Specialists Bob Black and Ed Gilman.
Are we getting warmer?
Most avid gardeners are familiar with USDA Hardiness zones, which are seen on maps of the U.S. as bands of regional minimum temperatures stretching from east to west. In a column last spring, I mentioned that these zones are based on actual weather data collected before 1990. The National Arbor Day Foundation recently examined current data from 5,000 national weather stations. Their review indicates the local boundary between zone 9 and 10 ought to be moved northwards. If these minimum temperature averages hold true over the next few years, successful landscape plant selections for Indian River could be made more tropical.
Choosing the more tropical palms for our Florida Yards may make local landscapes fit our image of paradise. But there are many other factors to consider in selecting these plants. Soil acidity/alkalinity, moisture, fertility requirements, ultimate size, pests, initial plant cost and the level of effort needed to maintain a plantís appearance all need to be considered before planting.
Our area has demonstrated several different palm species generally have been proven successful. Among them are many of the Date Palms (Phoenix spp.), Fan Palms (Livistonia spp.), Washington (Washingtonia spp.), plus our native Cabbage Palm (Sabal palmetto) and Saw tooth palmetto (Serenoa repens). If we take a look at other landscape palms under local conditions and management practices, some of the underutilized "Zone Ten" palms might add diversity to our Florida Yards - as long as Jack Frost will indeed take his winter vacations well away from our area.
Try these Tropicals
European Fan Palm (Chamaerops humilis) is native to the dry climates of southern Europe, and produces a clump of heavily thorned fan shaped fronds. Keep them on the dry side and watch for sucking insects which can quickly cover the blue-green fronds with black sooty mold. This palm will serve as a low-maintenance accent palm where the height available is less than 15 feet.
Bismark Palm (Bisamarkia nobilis) is one of the Florida Nurseryman and Growerís Associationís Plants of the Year for 2002. With broad fan-shaped silver blue fronds, it makes a bold tropical statement in Florida Yards. Give it plenty of room, at least 20 feet from other plants or buildings, and donít try to move it until the trunk is well formed. It is drought and salt tolerant.
Needle Palm (Rhapidophyllum hystrix) is a Florida native palm. It is very slow growing, and as a result, will be more expensive that other palms. True to itís name, it is heavily armored with sharp needles among the fibrous matting on its trunk. The palmate leaves are darker green above and silvery below. This small palm can be a long-lasting low maintenance fixture in the landscape, and will form a three to five foot tall clump.
Paroutis or Everglades Palm (Acoelorrhaphe wrightii) is one of my favorite palms that is a Florida native of the Cape Sable area. Paroutis Palms sprout into clumps that can reach up to 25 feet tall. The fan shaped fronds are heavily armored, and the clump will need periodic thinning for it to look its best. Paroutis Palms do well in wet locations, but do need to be provided with palm fertilizer to prevent yellowing. There is one growing in front of our office, and another fine specimen was enjoyed by the late Dr. Mike Baker in his front yard. ("Doc" was a 13 year Master Gardener volunteer in our office, and was Chairman of the Vero Beach Tree Commission.)
Foxtail Palm (Wodyetia bifurcata) is gaining favor in our Florida Yards. Its smooth trunk can grow up to 30 feet tall, and its arching fronds resemble a fox tail, which give it its name. With moderately fast growth, good drought tolerance and a mild tolerance to salt and sweet soils, it may be a better choice than more commonly used landscape palms.
Pindo Palm (Butia capitata) looks at first glance a bit like our state tree, the Cabbage Palm, but because it can hybridize with the Queen Palm, some specimens may have variable characteristics. Its feathery fronds have a distinct blue-green color. The coarse trunk may reach 20 feet tall or more, but it will take time to get there. The salt and drought tolerance of the Pindo Palm is high. The orange fruit can be used to make preserves, and give this palm its second name, the Jelly Palm.
Palms with problemsThe Coconut Palm (Cocos nucifera) in the minds of many is THE palm tree that makes the tropics. Their use in our landscapes has been recently on the rise, but ought to be limited because they are very cold sensitive and are susceptible to an incurable virus disease known as Lethal Yellowing. If the site is protected from cold, and if the golden fruited "Malayan Dwarf" type coconut palm that has resistance to LY is used, local residents may enjoy their taste of the tropics for a period of time. If these factors cannot be assured, the Coconut Palm will become nothing more than a expensive "annual" that will have to be replaced.
Royal Palm (Roystonia sp.) The large smooth gray trunks and boldly arching feathery fronds may be tempting to homeowners. However, remember that only a few survived locally during the freeze of 1989. And, unless you have a large estate with tall buildings, leave this 50 to 80 foot tall palm to public planting locations - it will look out of place in the average residential yard. You can enjoy them in places like McKee Botanical Garden, and in several places along, where else, Royal Palm Boulevard/Place/Point in the City of Vero Beach.
Adonidia or Manila Palm (Veitchia merrillii) has recently re-appeared in local nurseries. It gives the look of the Royal Palm, but its 20 foot height is much more appropriately scaled to residential areas. It has red fruit at Christmas, which gives rise to its other name, the Christmas palm. So why is it not on my recommended list? It is one of the most highly sensitive palms to Lethal Yellowing, the killer that eliminated Coconut Palms from much of south Florida.
Queen Palm (Syagrus romanzoffiana) - the "Plumosa" Palm - is one of the most commonly used landscape palms in our area. They can top out at 40 feet and provide bold arching feathery fronds in no time flat. Itís fast rate of growth means it is fairly inexpensive. But on our sweet, alkaline soils, if adequate palm fertilizers are not regularly supplied, they will yellow and develop "frizzle top". The best looking Queen Palms are growing so fast that they need constant pruning to remove brown fronds and the messy seed branches. Do you really want to spend your time pruning and picking up?
The Majesty Palm (Ravenca sp.) has attractive flat arching fronds but does not have messy fruit to clean up. There is some discussion on the species differences: one will reach 20 feet while the other may exceed a 50 foot height. This palm may do well in better soils and shady areas, but like the Queen palm, it will require lots of palm fertilizer if planted in sandy soils or marly fill soils which are common around developed sites.
The Areca Palm (Chrysalidocarpus lutescens) carries many other common names; the Butterfly Palm and the Golden Cane Palm are also marketing monikers for this clumping palm. It is probably the most commonly sold potted indoor palm, but when used as a landscape screening plant, sufficient room must be given for its 30 foot tall sugarcane-like stems that may crowd fences or buildings. Thinning is a must; and without attention (or a hard freeze), it may become a security hazard if placed too close to the home.
If you need additional information on selecting or using tropical palms, visit our Master Gardeners, or call or stop by our office. For those with other questions about Florida Yards, our office holds Master Gardener Clinic hours at the Extension office (1028 20th Place, Suite D, Vero Beach) every weekday morning and most afternoons, Wednesday morning at the Sebastian City Hall Council Chambers in Sebastian, and the first Saturday of the month at the Environmental Learning Center. Our phone number is 770-5030, and you can e-mail us at Indian@mail.ifas.ufl.edu . Happy Palm Sunday!