December 14, 2009
What’s Blooming: Sweet Gum’s Bittersweet Horticultural Legacy
On the south side of the creek that meanders through the Arboretum’s Meadowbrook section three tall, upright trees can be seen right now covered in brightly colored fall foliage. Commonly called “Sweet gum,” Liquidambar styraciflua, is native to Central America, Mexico, and the Southeastern United States where it is a significant percentage of newly regenerated hardwood forests. Liquidambar grows rapidly in regenerating forests because it has the ability to fix nitrogen in the soil. Liquidambar’s name derives from the liquid, amber-colored, resin the tree produces to protect itself from insect attack. This resin has been used by Native Americans in Mexico and North America as a chewing gum and as a medicine for healing wounds. The Aztecs were even more creative with the gum, using it as ceremonial incense and adding it to smoking tobacco to create a potent sleep-aide. Liquidambar wood is beautiful; polished cross sections reveal red heartwood surrounded by a contrasting band of bright white sapwood. Unfortunately the moisture content of the wood and its poor durability make it almost impossible to work with; items made from the wood warp and wear out rapidly. Furniture makers can still exploit the Liquidmabar wood’s natural beauty by applying it as a veneer to furniture constructed of more durable but less beautiful woods like pine. During the late 1970’s and throughout the 1980’s, Liquidambar styraciflua was an extremely popular landscaping and street tree. Three varieties introduced in the late 50’s and early 60’s by the Saratoga Horticultural Foundation in Palo Alto came to dominate the California urban landscape because of their pleasing forms and reliable fall coloration. ‘Palo Alto’ has orange and red fall leaves, ‘Festival’ has a confetti-like combination of red, yellow and pink, and ‘Burgundy’ is a variety that reliably turns a dark red here in late fall. These are the varieties planted along the stream in the Meadowbrook section.
For a while Liquidambar seemed like the perfect tree for California; a deciduous tree that seemed to thrive here and gave migrants from the east coast a taste of the colorful fall display of leaves they were used to back home. It was also fast grower that didn’t get out of bounds (cultivated Liquidambar rarely get over 60-70 feet tall) and a tree that seemed to thrive anywhere because of its nitrogen fixing abilities. But when the Saratoga Horticultural Foundation introduced the trees they paid little attention to a characteristic of the tree that would later create what could be termed a horticultural disaster. As Liquidambar matures its nature changes; the trees develop a propensity to form damaging surface roots and their production of spiny seed-balls increases. This makes mature Liquidambars quite a nuisance and liability; a fact that many property owners and cities would become painfully aware of after removing tens of thousands the trees and repairing the expensive damage caused by them to nearby structures. A study published in Western Arborist that surveyed tree damage in several Southern California cities found that the ubiquitously planted Liquidambar accounted for the greatest number of trees causing damage. In the city of Alameda it was found that 69% of the Liquidambars planted in that city were damaging or starting to damage structures. Currently Liquidambar styraciflua is not the easy landscape choice it used to be, but it still has advantages in some situations; it is now recommended that the trees be planted in locations that are at least 15-20 feet from any structures, and in areas where their copious production of spiny seed balls is not a problem. They should never be planted as street trees.
December 1, 2009
Member Profile: Virginia Russell
1. What is your earliest memory at the Arboretum?
When I moved to Arcadia in 1968, I believe at that time the entrance was free and the natural settings were just majestic and beautiful.
2. What is your favorite place in the Arboretum and why?
Down by the waterfall, it is the most peaceful and serene place for reflection. There are not many places left like the Arboretum and the preservation of this jewel should be on everyone’s minds and hearts.
3. Why and how are you supporting the Arboretum?
There are so many ways I enjoy supporting the Arboretum. I have donated stock, purchased tickets to events like the LA Garden Show Preview Reception, enjoy many cups of coffee at the Peacock Café and that’s just to name a few off the top of my head. I support this wonderful place because it is one of the few green spaces left for future generations. I brought my grandson and he had not seen peacocks until that day, it would be a shame if his son someday cannot come and see the peacocks and enjoy nature right in the middle of the city.
Support The Arboretum for future generations.
The Arboretum has flourished for over 60 years as an educational and environmental organization focusing on unique plant collections, book collections, and historic preservation. This historic landscape is the setting of many rich cultural stories shared with us daily–from the days when this was part of a private ranch and residence to the present when visitors enjoy the beauty of the natural world in the company of the wildlife that inhabit the area.Donate NowBecome a Member NowVolunteer Now