Duranta, even though it is commonly known as sky flower, is not named after Kevin Durant, a 7 foot tall basketball player who launches himself skyward on a regular basis. Indeed, the notoriety of Duranta, the plant, is not nearly on the level of Durant, the $25 million dollar a year NBA star. But maybe it should be. The name sky flower, in fact, is not in any way a reference to this plant’s stature, which is more on the scale of a large shrub than of a tree, but rather to the color of its large hanging clusters of bluish flowers. Varieties whose flowers are either white or purple with white trim are also available, as is ‘Gold Mound,’ a dwarf cultivar that grows only eighteen inches tall.
Duranta erecta (also known as Duranta repens) came to mind the other day while perusing an email from Sheila Brenton. “I am in the midst of a pool remodel due to root damage to deck and pool from tree roots,” Brenton wrote. “As a result, I’ve had to remove several palm and ficus trees. This has has left me with no privacy from neighbors. I was hoping you could advise me on what to plant that will give me back my privacy. Looking for an evergreen that is tall, quick growing, hardy,clean and drought resistant. I live in the foothill of Rancho Cucamonga (zone 10) so soil is quite rocky. One area is about 3 and 1/2′ wide by approx 40’ in one area and another is about 5 ‘ wide by 25 feet.”
I do not know how high you require your hedge or screen to be, but I have seen a wonderful cultivar of sky flower known as ‘Sheen’s Gold’ at a height of seven feet and, who knows, it might get taller. ‘Sheen’s Gold’ is the only golden yellow hedge I know of other than Euonymous ‘Old Gold,’ a standby in the nursery trade not only useful as a low hedge but as an evergreen perennial accent whose bright and sunny visage is on display 365 days a year. The standard, green-leafed Duranta erecta, by the way, when properly trained, will grow quickly to a height of ten to twenty feet.
Having rocky soil suggests you should work compost into these areas prior to planting, no matter which species you ultimately select. As in any area of work, selection of the right tool when adding soil amendents can make all the difference in the world. A spading fork has thick tines that make it easier to incorporate soil amendments than it would be with a shovel or spade, the latter being a flat shovel which is also used for this purpose but will require more effort to do the job than a spading fork. Beginning gardeners may confuse a spading fork with a pitchfork, the latter coming in handy for baling hay, as part of a Halloween costume, or in a political protest, but not of much utility in the garden.
A few caveats regarding Duranta should be mentioned. This plant is also known as golden dewdrops on account of the color of its abundant fruit which, although ornamental, is poisonous. This fruit is also consumed and then excreted by birds which has led to this plant’s status as an invasive species in more tropical climates than our own. But in arid Los Angeles, at least, Duranta is utterly tame. In addition, the natural growth habit of Duranta is arching or fountainesque. This means that it can be trained up an espalier lattice or encouraged to spill over a block wall. If you wish it to grow into a hedge, you will need to prune out any growth that shoots outside the boundaries of the hedge you have in mind, at least for the first few years, until it begins to fill in the area you have in mind. From that point forward, a hedge trimming two or three times a year will be sufficient to keep it within bounds.
Duranta can handle a freeze just fine, at least down to 25 degrees Fahrenheit. Although it does not top the list of drought tolerant plants, the fact that it will be growing in a narrow planter means that most of its root system will be under hardscape that not only seals off evaporation from the soil below but also keeps roots cool, and unstressed roots invariably impart a significant degree of drought tolerance to any plant. Notice that trees situated in asphalt parking lots or in concrete parkways, even when young, are seldom, if ever, watered except by winter rain.
Two privet species come to mind as hedge possibilties. The most robust choice would be glossy leaf privet (Ligustrum lucidum). This is probably the toughest evergreen hedge plant you could choose. It grows rapidly and is drought tolerant. You can let it grow to any height. The one drawback is its fruit, which can be messy. However, you can eliminate this issue by spraying its flowers with a product that prevents fruit from developing or by simply pruning off its flowers before they can set fruit. California privet, which is available in both green leaf and green and gold variegated leaf versions, produces a mass of fragrant flowers in the spring. Paperbark (Melaleuca quinqunervia) is also sometimes grown as a hedge in a confined space but you will want to line each side of your planters with a modular root barrier down to a three foot depth to keep the roots under control. Another species you might want to consider, although it is slower growing than those mentioned above, is the California bay tree (Umbellularia californica), which handles both sun and partial sun exposures. A relative of the bay laurel tree, its leaves may also be used in cooking, albeit in smaller quantities than conventional bay leaves due to the greater pungency of California bay leaves.
Tip of the Week: Another option for creating a screen in a narrow space is a sturdy metal trellis, which may be constructed to any height that you desire, accompanied by planting of your favorite vining plant along side it. Of course, this means an initial investment in the trellis but you would not have to worry down the road about roots pushing up the surrounding hardscape. Star jasmine (Trachelospermum jasminoides) is an excellent choice of a vining plant in this regard as it grows reliably in both full sun and partial sun exposures. For full sun, bougainvillea would be a sensible selection as well as any of the trumpet vines, in colors that include yellow, orange, red, and purple.