I would like to know how much I should water my carrotwood tree. I also wanted to know when and how much I should prune it.

>Steve Voigt, Downey

The carrotwood tree (Cupaniopsis anacardiaoides), like many tree species native to Australia - including eucalyptus, paperbark (Melaleuca) and bottlebrush (Callistemon) - is a highly adaptable tree, only more so.

In Southern California, carrotwood grows rapidly to a height and girth of 30 feet in a variety of soil types and endures both drought and overwatering without complaint.

It makes itself at home in sandy or clay soil, whether inland or on the coast.

The advantage carrotwood has over its Australian compatriots is that it does not get chlorosis, a condition brought on by alkaline soil and characterized by yellow leaves with green veins.

Carrotwood does have its drawbacks, however.

Like most other small to medium-sized ornamental trees (such as flowering pear, purple-leaf plum and crape myrtle), carrotwood starts to lose its luster within two decades of planting. It also does not grow well in windy areas. Named for its interior orange color, carrotwood is not especially cold-hardy and is thus unsuitable for the Antelope Valley.

In more tropical climates, such as south Florida, it has become an invasive, weedy tree that has smothered native plant communities in which it gained a foothold. Its sticky seeds, which adhere tenaciously to sidewalks, are disseminated far and wide by birds.

In our area, carrotwood's main problem is a structural one.


Here I speak from personal experience since, about a dozen years ago, a stout carrotwood stood in the parkway (that strip between sidewalk and street) in front of my house. One morning, after a windy night, I walked outside and found the tree had split in two.

Carrotwood branches, you see, have a tendency to grow out of the trunk from the same point. In time, as the branches get heavier, there is enormous stress placed on this point of branch origin, referred to as the "tree crotch."

Eventually, unless some of its large limbs are pruned off, breakage may occur. The deciduous ornamental pear (Pyrus calleryana `Bradford'), by the way, exhibits this habit of growth to an exaggerated extent, as does the coral tree (Erythrina caffra).

Carrotwoods grow rapidly during their early years and should be pruned frequently so that major branch development is staggered, no matter how slightly, along the trunk. After the primary limbs are in place, only occasional, light pruning is needed.

Ask a homeowner about tree pruning and you will get a sigh of weary resignation in response.

Tree pruning is an endless pursuit, made costly by the close proximity of trees to structures. We want to live in an urban forest but should try to keep that forest, in terms of planting distance, at least 30 feet from our walls.

It is notable that the city of Los Angeles is on a schedule to prune street trees every nine years. I have not noticed that the health of street trees has suffered as a result. It would seem that tree health is not determined by frequency of pruning.

Why do we prune trees close to our houses more frequently? Probably because they grow against our windows, drop dead or split branches on our roofs, interfere with utility wires, block sunlight or, hemmed in and leaning toward the sun, threaten to fall over.

Fuchsia success stories

Helen Mulliner, who lives in Woodland Hills near Mulholland Drive, wrote about her success with fuchsias:

"A fuchsia I bought at Trader Joe's several years ago, with red and purple flowers, has grown to 3 feet high and flowers profusely and continuously. It grows in a large pot under a Shamel ash and gets partial sun. I fertilize it once a week with orchid food (Grow More Urea Free 20-10-20) at half the recommended dose.

"I also have a `Gartenmeister' fuchsia, which is treated the same way. A third fuchsia is growing in a hanging basket under a tree. When the weather gets too hot, I take it down and put it among my ivy until the heat subsides. All my fuchsias suffered frost damage but, after pruning, returned to full vigor."

Nancy Hall of Porter Ranch got creative with her fuchsias:

"I made numerous attempts to grow fuchsias to no avail," wrote Hall. "However, I decided to plant one in a large self-watering pot and I have beautiful flowers most of the time ever since. The pot is located on a patio which has a slat cover. The yard is shady most of the day. I am very careful to keep the reservoir filled and occasionally add a few drops of Schultz fertilizer. Surprisingly, the extreme winds up here don't bother it."

Tip of the week

I recently learned about a remarkable plant that flourishes on the slopes of Mount Ryoko in Japan. It is a daylily (Hemerocallis thunbergii) that grows to a height of 7 feet. (Daylilies are typically around 2 feet tall.) The flowers are brilliant yellow and sweetly fragrant. This plant grows to its full height two years after being transplanted from a 2-inch pot. In the same period of time, it will have formed a clump 2 to 3 feet in diameter.

You can acquire this giant Japanese daylily from a nursery in West Virginia called Sunshine Farm and Gardens (www.sunfarm.com).

Joshua Siskin's column appears every Saturday. He welcomes questions from readers and will answer them in his column once a month. If you have a question, please send an e-mail to Joshua@garden18.com. Include your full name and the city you live in. His Web site is www.garden18.com.