April Tree of the Month: Victorian Box

By David Gress

The sweet perfumed air that has been wafting through Santa Barbara for the last several weeks is scented, in large part, from the “Victorian Box Tree”.  When one is in full bloom, it exudes a strongly heady fragrance, a blend of orange and jasmine, that is almost overwhelming!

Bell-shaped, cream-white flowers, ½ inch long, appear in 3-inch clusters at the ends of branches, all over the canopy, and bloom in profusion from late February through April.  Their copious nectar attracts great numbers of bees and, often, Anna’s Hummingbirds. 

After pollination, orange-colored roundish fruit capsules (berries), ½ inch in diameter, appear in the fall.  In the winter when the fruits mature, each capsule breaks open to expose 20-30 angular seeds, 1/8 inch-long, which are smooth, reddish-brown, and remarkably sticky. 

These tasty seeds draw in birds (particularly warblers and mockingbirds) which swallow and, eventually, spread them abroad – complete with a good dose of guano as fertilizer.  Consequently, baby trees may appear seemingly everywhere in the garden!  Victorian Box was considered for addition to the invasive plant list in California in 2013 but was not included, because the impact risk was deemed too low.  Fallen flowers and sticky resin-coated seeds are produced in such great numbers that they can be a temporary maintenance problem on walkways and patios.

Distinctive and appealing characteristics of the Victorian Box include its evergreen, glossy, dark-green leaves, 3 to 6-inch long, which have uniquely wavy edges, and its mottled gray bark that forms scales with age.  It is fire-resistant and, therefore, good for defensible space. 

When left to form into a tree in ideal growing conditions, a Victorian Box can grow to over 50 feet tall with a dense, rounded, umbrella-shaped crown in a spread of 40 feet.  However, this versatile plant is more frequently pruned from its start to become an attractive and functional evergreen shrub, screen, windbreak, or hedge – it is commonly used for this purpose in Montecito’s “Hedgerow District”.

Victorian Box is native to the east coast of Australia, appearing as an understory plant in Eucalyptus forests from south-east Queensland to eastern Victoria.  Having been quite popular for a long time as an ornamental tree, it has been carried to many of the tropical and subtropical regions of the world. 

Considering its moist tropical origins, it is surprisingly tolerant of drought, fog, and gusty or cold winds.  Unfortunately, after 7 years of our drought, many local Victorian Box Trees have begun to show signs of severe dehydration stress and, in some cases, have died.  Since they are susceptible to “oak root fungus” (which is common in Santa Barbara County soils), they can also die, ironically, from overirrigation or too much rain. 

Its botanical name is Pittosporum undulatum.  Pittosporum is a combination of the Greek words “pitta”, meaning pitch, and “sporum” meaning seed, referring to the resinous coating on the seeds.  The specific epithet, undulatum, is from the Latin word “unda”, meaning wave or surge, referring to the wavy (undulating) leaf margins.  Its other common names are “Australian Cheesewood”, “Sweet Pittosporum” and” Mock Orange”. 

Victorian Box Tree should be planted in sun to partial shade. Since it is naturally an understory plant, it can do well under larger trees.  While drought-tolerant when established, it does better with deep watering during dry periods.  It does well in all types of soil, but always requires good drainage.  Aphids are the only insect pest that seems to bother it – aphids can be easily controlled by occasionally spraying the tree with water or with organic pesticides.    

There are many fine examples of Victorian Box Trees in Santa Barbara: as street trees, they are found on Micheltorena Street (from Chapala to the freeway), on East Micheltorena Street, on East Sola Street, on East Victoria Street, and on the 400 Block of East Figueroa Street; and, as park trees, they have been planted in Orpet Park and in West Alameda Park.  Of course, there are innumerable Victorian Box hedges bordering private residences – and perfuming our yards these evenings.

Tree-of-the-Month articles are sponsored by Santa Barbara Beautiful, whose many missions include the increase of public awareness and appreciation of Santa Barbara’s many outstanding trees and, in a long-time partnership with the City Parks & Recreation Department, the funding and planting of trees along the City’s streets – a project which has resulted in the planting, to date, of more than 12,000 street trees.