Date: Fri 03-Sep-1999

Publication: Bee

Author: SARAH

Quick Words:

Gardener-Bleach-trees

Full Text:

SUBURBAN GARDENER: Dry Summers And Big Trees

By Anthony C. Bleach

The summer of `99 was the best time to read The Flamboyant Garden by Elisabeth

Sheldon. If we are in for a succession of Sahara summers, we should forget the

pinks and pastels of the English tradition and design with flaming oranges and

reds and passionate purples.

A garden which exemplifies this with audacity is Wave Hill. The flamboyant

garden has some good ideas for our own gardens. It was also the worst of times

to have a lawn. Suburbia has turned into one huge hay field. This fall I will

forget the traditional blue grass and resow with coarse, invasive, tall

fescue. I am convinced that until Buffalo grass is available, this is the only

choice if you don't have an irrigation system.

Finally, this summer we have decided to plant more big trees. They give shade,

moderate temperature and humidity, deflect winds, give shelter to birds and

will be there long after we are gone.

I found this section from an article by Frederick R. Spicer, Jr in the

American Nurseryman Seminal .

For design purposes, the question of the mature size of potentially big tree

boils down to three questions:

1. How big will the tree get in a reasonable amount of time with regard to its

normal rate of growth?

If properly planted on a suitable site, a 7-foot-tall Eastern white pine can

reach 25 feet tall and 15 feet wide in 10 to 12 years. A ginkgo of the same

size planted at the same time might grow a little more than half as tall as

the pine.

Relatively speaking, this ten-year period is a much longer time for the pine

than for the ginkgo. There are ginkgoes in China and Japan more than 1,000

years old.

2. What shape will the tree have as it matures?

Remember that many trees have one habit in their youth and a vastly different

habit when older. The dense, young Eastern white pine matures into a tall,

picturesque, almost Gothic-inspired form, devoid of branches for much of its

height. The open, angular, almost awkward-looking juvenile ginkgo becomes a

gracefully spreading, imposing giant.

Think about this in terms of the landscape. If you plant a row of Eastern

white pine for a 6-foot tall screen, your design effect will be short-lived,

as the lower branches will quickly shade themselves out. You should have

chosen another plant, probably a shrub.

3. Will the tree have a reasonable chance of being allowed to grow to its

ultimate size where it is planted?

Eastern white pine can reach more than 100 feet tall, and ginkgo nearly the

same. (Remember not to confuse the tree's ultimate size with its relative

mature size.)

And while it is true that some big trees can be planted in tight spaces near

buildings and still grow naturally within the bounds of these sites or pruned

correctly over time to fit in places like these, it doesn't always work. Most

homeowners are unskilled or unaware of the need to maintain trees in this

situation.

Planting The Big Ones

If you have decided to plant some big trees, consider how close together they

can or should be planted. My personal feeling is that, unless the trees are to

be used in an architectural manner, they should be planted in multiples

wherever possible.

Trees planted to match or enhance the measured rhythm of an architectural

feature, planted in a grid (as in a bosque or an orchard) or planted as a

uniform allee, arching over a path, driveway or road, must be spaced evenly to

produce the desired effect.

However, to achieve a truly mature effect, use multiple trees and plant them

in masses, groves or copses (the preferred English term). To better simulate

nature, observe trees in fields, forests and other places to learn how they

grow relative to one another. Very often, their trunks are only a few feet

apart. Their relationships are seldom antagonistic and often seem synergistic.

In fact, closely planted trees grow taller more quickly than those spaced well

apart because their lateral growth is inhibited by their neighbors as they

compete for sunlight. Their roots intertwine, increasing erosion-control

efficiency and overall stability in high winds.

Closely planted trees of the same species may even form root grafts. This

phenomenon is not well understood, but research suggests chemical information

is shared.

This could stimulate unaffected trees to initiate early defensive responses to

pests detected in other trees via root grafts (for example, increased tannin

production). Some scientists believe nutrients, water and carbohydrates may

also be communal, being transferred through mycorrhizae.

Mass planting is particularly effective when using trees with interesting

bark. Anyone who has strolled through the inspiring grove of Calocedrus

decurrens (California incense cedar) at Longwood Gardens in Kennett Square,

Penn., or the breathtaking mass planting of Metasequoia glyptostroboides (dawn

redwood) at Morris Arboretum of the University of Pennsylvania in Philadelphia

will know precisely what I mean.

Resist the temptation to space plants according to your circle template and

plant some groves. They don't need to be immense -- if space is at a premium,

a grouping of three of five will suffice. Odd numbers are usually recommended,

but I think that argument becomes irrelevant after seven.

What is even more important is that the trees are spaced unevenly. Using trees

of differing heights also enhances the effect. Furthermore, people like the

appearance of multiple trees. Clump forms, especially of unusual species or

varieties, and multi-stemmed specimens have proven very popular.

In New Hope, Penn., there is a grand old Quercus alba (white oak) growing in

what is now an open field. It is approximately 70 feet tall, with a spread

reaching more than 100 feet and a trunk roughly 5 feet in diameter.

Long ago, the tree sent out a branch about 5 feet off the ground. This branch,

now about two feet thick near its trunk, emerges at a right angle and proceeds

outward some 60 feet, dipping majestically once or twice, closer to the

ground, as if daring the elements to test its strength. On the tree there is a

plaque stating the white oak was approximately seven years old when Columbus

landed in the New World.

To me, this tree is a paradigm of distinction, endurance and nobility. I hope

one day, someone will look at a tree I planted, or a tree you planted, and

feel the same way.

(Anthony C. Bleach coordinates the horticulture degree program at Naugatuck

Valley College in Waterbury.)