How to Grow and Care for a Carrotwood Tree

The carrotwood tree, also commonly called by its botanical name Cupaniopsis, is an evergreen tree in the soapberry family widely used in California coastal areas as a street tree. Carrotwood trees feature attractive leathery leaves and whimsical blooms that grow best in warm, humid, swampy regions, thriving in full sun conditions and nutrient-rich soil. The pH and soil type don't matter much to this plant. These trees can be grown indoors, provided they have enough light and warm temperatures.

Carrotwood Tree Care

Here are the primary care requirements for growing a carrotwood tree:

• Keep in a warm climate that receives full sun.
  
• Plant in enriched, nutrient-dense soil that drains well.
• Maintain high humidity in its immediate environment.
• Feed with a high-nitrogen fertilizer twice a year to support growth.

Light

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 the growth rate if planted in a shadier spot, so plan your landscape design accordingly.

Soil

Carrotwood trees benefit from being adaptable regarding soil, though they naturally prefer sandy locations. Planting it in an area 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.

 Water

Carrotwood trees are unique in that they thrive in hot and humid environments and require less water once established. Water them consistently during the first year, about once every one to two weeks. After that, you can taper it off and only irrigate in droughts or dry spells. Watering occasionally will keep the tree content. Because these are evergreen trees, there will be no period of dormancy.

Temperature and Humidity

Carrotwood trees thrive in hot and humid areas and should not be placed in areas that are too cold or lack moisture. As of right now, its habitable zones are USDA 9 to 11. They are only invasive in Florida, Hawaii, and coastal regions in those zones. As the climate shifts, the habitable zones may change, causing the species to become more invasive in other areas.

Fertilizer

The carrotwood tree usually demands supplemental fertilizers, even when planted in less-than-ideal soils. If your tree lags, 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 to give a little helping hand to an ornamental tree.  

Types of Carrotwood Trees

There are no cultivars or varieties of Cupaniopsis anacardioides other than the wild type. To identify a carrotwood tree, look for smooth gray outer bark and orange inner bark with alternating leathery leaves. Carrotwood trees produce white, non-descript greenish-white flower clusters in winter and woody orange and yellow fruit capsules that appear in clusters in summer. The fruits have three lobes or ridges.

Pruning

Pruning is usually 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 significantly but can lend a wow factor when in bloom and planted as a specimen.

Unlike most trees, you can do this job at any time of the year since the carrotwood is a tropical evergreen with no dormant period. All you will need is garden shears, loppers, a pruning saw and alcohol or a concentration of water and bleach diluted 10:1 to clean your tools. Here's how:

1. Remove any dead, dying, damaged, or broken branches. Use your pruning shears for anything cutting branches up to 3/4 inch in diameter; use your loppers for anything larger up to two inches. Beyond that, employ a pruning saw using the proper technique.
2. Assess the tree once these branches are gone and see what more it needs.
3. Move on to the interior canopy, look for branches directed towards the trunk, and remove those branches.
4. Remove any "X" intersections, rubbing branches, or branches that may cause overcrowding.

When the tree gets to a point where the job can only be done by ladder, it is usually best to call in a professional certified arborist,

How to Grow Carrotwood Trees From Seed

Carrotwood trees can easily propagate from seed when given a warm, humid environment to thrive in. Since birds enjoy the fruits, they become the primary seed dispersal method causing the invasiveness problem in Florida and Hawaii. When you mimic their ideal growing conditions, germination and fast growth are practically assured. Follow these steps to grow a carrotwood tree from seed:

1. Allow seeds to dry on the tree.
2. Remove the seed pods and remove the fleshy coating of the fruit to reveal the seed.
3. Soak the seeds in warm water overnight.
4. Place the seeds on top of a well-draining, compost-enriched potting mixture. Lightly cover the seeds with a scattering of the potting mix.
5. Keep the soil moist but not soggy.
6. Watch for germination in two to four weeks.
   

Potting and Repotting Carrotwood Trees

A carrotwood tree can be grown in a container as long as the vessel has adequate drainage and is deep enough to accommodate the roots. It's best to start with a pot that's at least 12 inches deep with drainage holes on the bottom. Fill with a combination of potting soil and compost and add a layer of mulch around the tree's base.

Carrotwood trees should be repotted after they double in size or at least once a year, depending on what comes first. The tree should be removed by gently loosening the roots out of its existing pot. Set in the new pot at the same depth and fill in around the roots with your fresh potting mix and compost. Water the tree thoroughly to help the soil settle, and make sure it's placed in a sunny location. If keeping the tree indoors, a spot that is about a foot from a window is perfect.

Common Pests & Plant Diseases

Few pests bother carrotwood—a big reason why this tree is so invasive. You may see insects on the tree, some causing damage, but the damage won't threaten it. 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 preventing and removing 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 Problems With Carrotwood Trees

The carrotwood tree is straightforward to manage once it has matured. But you may have to contend with unsightly leaves.

Yellowing Leaves

Yellowing leaves usually indicate something is wrong with your carrotwood tree. They can be anywhere from the tips to the edges, but they definitely signify an underlying issue. They may be accompanied by curling, browning, and wilting. First and foremost, test the soil to see if there's a nutrient deficiency. Then, feed with the appropriate fertilizer.

At the same time, assess the tree's moisture needs. Too much water can drown this tree and leave it in distress, but too little will leave it parched. Adjust your watering schedule according to the moisture levels of the soil.