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Two Citrus Trees.
Left tree
: Trunk has good taper, a few more
lower branches would be better, canopy is green
and healthy. Top of soil has many exposed roots
that are still flexible. It would be a good buy.
Right tree
: Trunk is slightly tapered, too
many lower branches have been removed,
and branches have signs of leaf drop. Drought
stress? Root impact? The tree will recover but
will have a poor start.
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From the
Summer 2007 MALP Newsletter
By:
Ernie Rezents ISA Certified Arborist, and ASCA Registered Consulting Arborist
Last month Susi Mastroianni wrote “How to Plant a Tree”. This article will complement hers by discussing considerations
you need to make when selecting a tree you want to plant.
It is important to buy the right tree because trees are a big investment. There is the initial cost of buying the tree,
the cost to haul and plant it, and the long term costs to care for it.
You cannot plant a tree and walk away, especially when planting in an urban environment where survival challenges
are more intense than if the tree were growing in its natural habitat. The tree needs to be watered, fertilized,
pruned occasionally, and have its rubbish raked and picked up.
But the benefits more than make up for the costs. When grown long term, trees provide: great cooling shade, colorful
flowers, fruit, architectural enhancement of a structure, increase of property value by as much as 10-12%,
habitat for wildlife, a sound and visual barrier when properly placed, a decrease in rain water runoff, the oxygen
we breathe, a decrease of carbon dioxide, a reduction of global warming.
Prior to buying the tree, you need to know:
- The Site
- Unfortunately trees are not adaptable to all the site
variations found in our typical landscape. The Maui County Planting
Plan shows five environments that plants are exposed to: Wet
areas - windward part of the island; cool, dry areas in higher elevations
above 1,000 feet; low, drier areas that are warm to hot; lower
elevations that are wetter due to proximity to mountains; and salt
spray zone in costal areas on the
windward sides of the islands.
In addition to these environmental
conditions one should be
aware of site conditions such as
soil pH, salinity, and depth, and
whether there are underground
water and utility lines. An adequate
above
and below ground space is needed for a full tree canopy to be
supported by a large root mass.
- The Species
- References such as Plants for Tropical Landscapes,
A Gardener’s Guide by Rauch and Weissich, A Tropical Garden Flora
by Staples and Herbst, Guide to Landscape Palms by Meerow, and of
course the Maui County Planting Plan by the Maui County Arborist
Committee are some of the many references available for your use.
In addition, your personal experience with the species, or just seeing
how it does in the neighborhood you want to plant it, will give you
some idea whether that tree is suited for the chosen site.
The Maui County Planting Plan (MCPP) contains 21+ characteristics
(canopy spread, wind and salt tolerance, planting zone, etc.) for
many of the commonly planted trees, ground covers, and turfgrasses.
It does not include fruit tree information because they are not planted
on streets and in parks. You can get a copy by contacting the County
Parks & Recreation Department and paying a minimal price. This
document is being revised and will include new plants but no invasive
species. It will include new chapters on parking lot trees and
invasive species. Completion
date is hopefully
two years away.
County Administration
support and Council
action are needed on
some important issues before the document is released.
- The Nursery
- Once you have the right species for the site you need to
find where it can be bought. Because of the busy construction period Maui
is experiencing many nurseries have placed on hold trees destined for
landscape projects in progress. Available trees frequently are off grade and
will need a lot of training. Healthy fruit trees are available at local nurseries
because they are continuously provided by nurseries such as Plant It
Hawaii and Frankie’s.
- “Eye Balling” the Tree
:
These three jacaranda trees are all trunk
- about 13 feet tall - and have no lower
branches. Their trunk taper is slight;
trunks are crooked. These trees will be
difficult to grow and train into having a
well branched canopy.
They are too leggy.
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- Roots:
Do not buy- a tree with woody roots circling a pot’s soil surface.
Tender soft roots circling can be opened-up at the time of planting. A tree
with woody roots sticking out of the drainage holes is a sign of being “pot
bound”. Do not buy it. I am known to shake out a tree from its pot and have
a look at its roots if I suspect problems. Years ago 3 & 4 foot citrus trees
came in one gallon pots. Woody circling and kinked roots were common.
The public became educated and rebelled. Today they are grown in large
grow bags or pots.
You want a tree in balance with its pot size. You want a tree to have enough
roots to hold onto the soil at planting. I have seen a pot carefully cut to
facilitate removing the tree and the entire medium fall away when the tree
was lifted. The roots hung like you were grasping the handle of a water mop. Panic!
Buy a tree whose size is proportionate with the pot to avoid “pot bound” problems. Roots should be white and not
brown or black.
- Trunk
: A single upright trunk is ideal. If only trees with multiple trunks are available, tip the weaker one(s) to subdue
them and let it produce photosynthates until the tree is growing well. Then remove the subdued leader(s) leaving just
one main leader.
If many of the young tree’s branches are growing upright at angles less than 45 degrees this will make for bark to
be included (squeezed) between the branch and trunk. If branches with included bark are retained, they are poorly
attached and may become problematic as they mature and become heavy.
Buy a tree with a single trunk with branches distributed around the trunk and emerge from the trunk at angles between
45 and 90 degrees. The trunk should be tapered, larger diameter at the bottom and smaller at the top.
- Leaves
: They should be evenly distributed on the upper two thirds of the tree and its branches. They should be green,
healthy, and free of insects; check both sides of the leaves for pests
.
Buy a tree that is vigorous, has many healthy green leaves, and has no insect pests.
In summation a healthy small tree growing in a container of a proportionate size will adapt to a site better and faster
than a larger tree with root, leaf, and trunk problems.
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