How to choose and grow a tree in Laguna

October 18, 2002

The Garden Fanatic

"October is the fallen leaf ...."

-- Hal Borland

"Old gardeners never die ... they just fade away."

-- Anonymous

There have been a number of defining moments in my life: the first

kiss, leaving Laguna for college and marrying Catharine come to mind


quickly. I also recall selecting my first tree for a client, and it

was Fritz Toohey who sold it to me.

I was thinking about Fritz last week, as I noted that the

liquidambars and sycamores had begun to turn color in and around

Laguna. It had been awhile since we had last chatted, so I promised

myself that I would call him soon. Later that day, my

ever-inquisitive wife asked, "Why do some trees turn color?" And I

answered ....

Trees are planted wherever one chooses, but grow naturally only

where they can survive and prosper. In the wild, environmental

factors determine success or failure for a particular species of


Northern latitudes and higher altitudes, as on our recent mountain

visit, are characterized by cold winters and periods of winter

drought (unavailability of water due to snow). Deciduous trees

(cottonwood, maple, etc.) must shed their leaves to protect against

adverse conditions, and are native to these climes.

The desert, which has an excess of summer heat, and Laguna Beach,

which does not provide sufficient winter cold, are inhospitable to

many species of deciduous trees. Although many cultivars of trees

provide fall color in Laguna, one must travel as far away as Maine,

or as close as Idyllwild, to view the truly spectacular turning of


Every broadleaf, deciduous leaf is attached to its tree by a stem

called the petiole. The petiole not only holds the leaf, but contains

the conducting pipelines, which carry water (xylem) to the leaf and

returns food (phloem) out of the leaf to the plant. This versatile

structure also rotates the leaf to the proper angle to receive more

sunlight and elongates to ensure that each leaf reaches enough light.

As a leaf matures, it changes in color from light green to darker

green. When temperatures become chillier and water becomes less

available, a biological signal is sent to the tree that winter is

approaching. From late summer to early fall, a ring of cork grows

across the petiole of many deciduous trees, slowly blocking the

pipelines of water and food to and from the leaf. These cork cells

are called incision cells. By early October, the conducting

structures of the leaf are completely sealed off. Depending on the

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