Native to Australia, the carrotwood tree (Cupaniopsis anacardioides) has made an impression in ornamental horticulture in the narrow region where it thrives since being introduced. The carrotwood's success has given places like California a beautiful new evergreen selection to plant in coastal areas as a street tree, while at the same time becoming so invasive in Florida and Hawaii that its planting and cultivation have been prohibited.
The carrotwood became popular because it is an attractive tree. That cannot be denied, providing year-round interest, attractive foliage throughout the year, whimsical blooms that give way to interesting brightly colored, and most of all, it is very easy to maintain. When introduced in Florida, these traits made the plant too attractive. It soon became too popular and an ecological disaster, which led to it having to be prohibited, but oddly enough, it was still available. Before planting, it would be a good idea to check with local ordinances and your state’s Environmental Protection Agency and Departments of Agriculture. Even if the tree is allowed in your state though, you should still consider planting a more ecologically responsible tree that is native to your area.
|Common Name||Carrotwood Tree|
|Botanical Name||Cupaniopsis anacardioides|
|Mature Size||40 ft. tall, 30 ft. wide|
|Sun Exposure||Full sun|
|Soil pH||6.0 to 8.5|
|Hardiness Zones||10-11 (USDA)|
Carrotwood Tree Care
Besides the care from occasional watering in dry climates and pruning to desired form or size, the carrotwood tree is very easy to manage once it has reached maturity. This ease of care is one of the reasons it has become so notoriously invasive in Florida and Hawaii. That level of invasiveness should be listed as among the care concerns, as a permit must be obtained to possess or grow the plant or seed in Florida. The species is of less concern in other states because of their drier climates. But, where there is humidity and swampiness, Cupaniopsis anacardioides has the potential to become invasive. Another tree might be a better alternative in these places, maybe the beautiful Gordonia lisianthus, loblolly bay.
No matter where your carrotwood is getting planted, you can ensure it will stay healthy by following a few easy and basic guidelines that will keep you and your tree happy for a long time.
One of the few demands the carrotwood tree makes is sun exposure. It needs full sun to thrive and stay healthy and vigorous. Plant it in an area that gets at least six hours of sun daily to ensure it grows to its full potential. A noticeable difference will be spotted in growth rate if it's planted in a shadier spot, so plan or make those considerations in your landscape design when choosing plants or site selection.
Carrotwood trees benefit from being adaptable regarding soil, though they naturally prefer sandy locations. Planting it in a location that provides moist, rich soil will guarantee its success, but the tree will also thrive in clay and loam. The pH of the soil is not a real concern either, with the species being able to manage slightly acidic and slightly alkaline soils.
The strange thing about carrotwood trees is that they thrive in hot, humid, and wet environments like the coastal areas of Florida and Hawaii but do not require much water once it is established. Carrotwoods do not take long to establish themselves and only need to be watered during that first calendar year using standards that are pretty normal, 10 gallons per caliper inch of trunk diameter. After the first year, you can taper it off and just water when there are droughts or long spells without rain. It is an evergreen, so you will base your first year of watering on a 12-month timeline from when you planted it since it does not have a dormant period. Water occasionally, and it should be content.
Temperature and Humidity
This is the one area that will outright make your carrotwood tree unhappy if you go outside the goldilocks zone and place it in an area that is not hot and humid enough or, much worse, too cold. The lack of moisture and the small area where cooler temperatures rein it in keep the carrotwood from becoming invasive in other locales outside of areas other than Florida, Hawaii, and coastal regions in its habitable zones. A fear that lingers in ecologists' minds as climate shifts cause the USDA zones to push southward is that the habitable zone of the species moves north, making its invasiveness more widespread. As of right now, its habitable zones are USDA 9-11.
The carrotwood tree usually has a high demand for supplemental fertilizers, even when planted in less than ideal soils. If your tree is lagging, adding an all-purpose slow-release ornamental tree fertilizer may help it reach its full potential. An NPK formula of 16-6-12 is a good value for an all-purpose fertilizer for giving a little helping hand to an ornamental tree.
Types of Carrotwood Trees
There are no cultivars or varieties available of Cupaniopsis anacardioides other than the wild type. This is unfortunate as it is attractive and can serve some horticultural purposes. With the production of a cultivar, the ability to easily reproduce and disseminate would be eliminated. This trait is one of the largest issues that cause the species to be invasive in especially receptive areas like Florida's hammocks (i.e., a dense stand of usually hardwood trees growing on a natural rise of only a few inches in elevation).
As a caregiver to a carrotwood, most are relieved to find out that pruning is usually not a labor-intensive job. Pruning is usually only done to form the tree, control its size, and keep overcrowding branches to a minimum. The species can be single-trunked or multi-trunked, which increases its spread greatly but can lend to a wow factor when in bloom and set by itself in a garden.
To properly prune a carrotwood, you will need the proper tools: shears, loppers, a pruning saw, and alcohol or a concentration of water and bleach diluted 10:1 to clean your tools. Unlike most trees, you can do this job at any time of the year since the carrotwood is a tropical evergreen and does not have a dormant period.
First, look for any dead, dying, damaged, or broken branches and remove them. Use your pruning shears for anything cutting branches up to 3/4 inch in diameter, anything larger up to two inches, use your loppers. Beyond that, use the pruning saw using the proper technique. After all of these branches are removed, step back and assess the situation and see what needs to be done.
Now go to the interior canopy, look for branches directed towards the trunk, and remove those branches. Look for any X intersections, rubbing branches, or branches that may cause overcrowding. Finally, once again, step back and assess and consider what, if anything, still needs to be removed, and remove only the very end of the branches and areas that may touch structures over trees.
When the tree gets to a point where the job can only be done by ladder, it is usually best to call in the pros, which means calling in a professional certified arborist.
Propagating Carrotwood Tree
The best method of getting a carrotwood tree for your landscape is through a trusted commercial dealer. As they are available online, it is possible to have them shipped into areas where they are prohibited from being sold, but the sale, distribution, and propagation are prohibited for a good reason. Where is not prohibited, they are easily commercially available and the propagation compared to the effort of buying a tree is not worth it. A viable tree for landscape use will take 5 to 10 years before maturity, so the best bet is to buy one set to go into the ground and avoid the wasted time and if you are in a prohibited area a possible hefty fine.
Common Pests & Plant Diseases
One last reason, and possibly the largest reason why the carrotwood is so invasive, is its lack of pests. It is not known to suffer from any serious pest issues, so if it is an area where it is not invasive, you are in luck; if not, you will see why it outcompetes everything else. You may see insects on the tree, some causing damage, but the damage won't threaten the tree itself. It may open the door to a threat, though.
While seemingly impervious to most native insect damage, it is not immune to disease. Two fungal issues are prevalent in the carrotwood tree Verticillium Wilt, which affects the tree across the continent, and Fusarium Dieback, a newer pathogen appearing only in Southern California. The best treatment for both diseases is the prevention and removal of damaged plant material.
Both diseases will be evident by yellowing and dieback. In cases of wilt, the foliage will wither and shed. In both cases, it is advised to call a professional to consult and advise on remediation measures. Any removed branches and waste should be removed from the site; this is best done by a professional who will dispose of it properly.
Common Issues With the Carrotwood Tree
As was mentioned but bears repeating, the largest problem in this country with the carrotwood tree that one may encounter is the possibility that it is illegal to grow one in your town. Before considering planting, purchasing, or designing with carrotwood, Cupaniopsis anacardioides, check your local and county ordinances and state regulations concerning the species.
How fast does the carrotwood tree grow?
You can expect the tree to grow fast, 12-24 inches a year in the full sun.
Are carrotwood berries edible?
Yes! They are edible and very sweet, and an Aboriginal treat known as a Tuckeroo.
Is the carrotwood an evergreen or does it lose its leaves?
The carrotwood is a tropical evergreen. It may drop some leaves, but it keeps most of them throughout the year and never loses all of them completely.
Florida Noxious Weed List. Florida Administrative Code & Florida Administrative Register.