March 29, 2009
written by Francis Ching
Lasca Leaves 20:37, 1970
For many years mulching practices at the Arboretum were carried on only to a limited extent. One reason was that since the Arboretum is adjacent to the Santa Anita Race Track, a great number of residents in the immediate area have always been conscious of flies and have related any kind of mulching and composting with fly infestation. Many times in the past, the Arboretum has been able to obtain manure as well as bedding material from race tracks, yet, despite thorough inspections by the County Health Department, the fly problem has been erroneously blamed on the Arboretum.
Another reason why mulching practices have been resisted is that it was thought the general public would not appreciate large mulched areas as compared to a well-manicured lawn.
Further, there was the question of salts and possible damage to plants from an accumulation of salts from manures. In the final analysis, it was determined that if manure were properly used as a mulch, salts, if present in even damaging proportions, would be leached away before being able to cause any damage.
A fear that slopes heavily mulched would be subject to severe erosion from heavy rains or irrigation practices was thoroughly discounted by a timely demonstration. Although mulching to any extent had not been practiced since the Arboretum was started in 1949, and plants apparently grew “all right,” serious consideration was given in 1964 to a review of its advantages. lt was well known that in the early days of development, whatever topsoil there was, was scooped up, pushed around and eventually lost. Not only were there hardpans present in many areas but surface layers were also compacted due to heavy equipment causing poor aeration and an intolerable condition for adequate infiltration and percolation of moisture. It was glaringly noticeable following heavy winds in 1962, 1963, and 1964 that many trees were lost due to uprooting. All of these uprooted trees possessed a very shallow root system which made them prime candidates for “pushovers.” In addition, during digging and moving operations of large trees, many of the plants also had a very shallow root system which made moving operations quite difficult.
Realizing the poor soil conditions, checks were made on actual moisture penetration. Even after a relatively heavy rainstorm of two inches in twenty-four hours, moisture penetration amounted to as little as two inches in some areas. Checks made after leaving rainbirds on for seven hours showed that moisture penetration was less than four inches.
Poor Root Systems coupled with poor soil moisture penetration brought the sudden realization that irrigation practices were insufficient. This situation was worsened by the fact that it had always been more important to irrigate according to the needs of the lawn, taking it for granted that the trees and shrubs were receiving adequate amounts of moisture.
Maintenance of a lawn in a heavily planted area poses many problems besides watering. Having to mow regularly between plants subjects plants to possible damage. On the other hand, if lawns are not adequately mowed, the area takes on an unkempt appearance. In order to keep all lawn areas mowed during the spring, summer, and fall months, six men were assigned to the task. This did not include the great amount of time necessary for servicing and repairing the equipment.
Besides mowing, it was also necessary to spend endless hours in hand trimming grass away from the base of trees and shrubs. When this is not done regularly during the summer months, Bermuda grass has a tendency to climb up into the low branches of shrubs and up the sides of tree trunks.
(This is the first part of a two-part article)
March 29, 2009
Your Aunt Etta left you her mammoth staghorn fern. It took three of your friends and a pickup truck to get it to your patio. It seems that being a dutiful nephew is now requiring you to ascend to levels of horticultural science that you would rather not traverse. All is not lost. The following is a short overview of staghorn fern culture that will help you preserve both the memory of your wonderful aunt, and the fern.
Staghorn ferns belong to the genus Platycerium and are native to tropical regions of Africa, Southeast Asia and Australia, where they grow on trees as epiphytes. There are perhaps 18 different species in the genus. The most common species grown in Southern California is P. bifurcatum, which will withstand temperatures as low as 20-22° [ degrees ] with only a lath structure for shelter. Several other species such as P. superbum, P. hillii, P. willinchii and P. stemaria are available from specialty nurseries. These species require greater protection from frost. Most of the remaining species require greenhouse cultivation.
Two Types of Leaves
Staghorn ferns produce two types of leaves or fronds. The sterile fronds are persistent, flat, and pale green, aging to tan and brown. They support the plant, enclosing the massed roots, rhizome and humus. Fertile fronds are deciduous, erect to arching or pendent and are divided into a few or many deep lobes. Due to the division, the fertile fronds resemble deer antlers. On the lower surface of the fertile fronds brown patches of spores form. The number and placement of the spore patches is distinctive for each species.
Potting or Mounting
The Staghorn ferns perform best mounted on bark, wood slabs, or slatted wood frames, furnished with moss and attached to the mount with either wire or nylon fishing line. They can also be grown on tree fern stem or, in the case of clumping species, in hanging baskets. Established plants will envelop whatever they are mounted on. All rely on atmospheric moisture rather than water directly at the roots. Daily spraying of the fronds during warm weather is beneficial with water being applied moderately to the roots. Fertilization is best applied as a monthly foliar spray on actively growing plants. Staghorn ferns grow best is bright shade or early morning sun , and will burn if given too much exposure to summer sun.
Propagation of clumping species can be performed by division of larger offsets in the spring. The rhizome is buried beneath layers of many dead, closely packed, sterile fronds. Cut through the layers of sterile fronds until the rhizome is severed and then mount it on a fresh support. Species which do not branch can only be propagated from spores.
The most common pests of Staghorn ferns are armored scale insects. Armored scale insects live their entire adult stage attached to one spot on the host plant. They have a waxy shell-like covering that protects them from natural enemies and insecticides. If the infestation is light they can be picked off rather easily. When a valuable plant is heavily infested you can clean off all the stationary adults and then spray with broad spectrum insecticide to control the crawling juvenile stage (first test the insecticide on your fern by mixing a small amount and then applying it to a small, inconspicous area of your fern).
Common Staghorn Fern
The common Staghorn fern is P. bifurcatum. The sterile fronds are up to 24 inches wide by 18 inches long. They are papery, erect, rounded to heart- or kidney-shaped, and shallowly or irregularly lobed on the upper margin. Fertile fronds are leathery and grow up to 3 feet in length. They can be erect, spreading, or pendent, and are 2 or 3 (occasionally to 5) times dichotomously forked. Their growth habit is clumping, producing new plants as the rhizome branches. There are a number of named cultivars such as 'San Diego', which has longer fertile fronds that are darker green. Platycerium bifurcatum is native to Southeast Asia, Polynesia, and subtropical Australia.
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