Chill Hours
Chill hours are the total number of hours under 45°F during winter
before the plant breaks dormancy.
The mountains of Arizona normally achieve 200-500 chill hours per year.
Plants needing more chill hours than your location provides may not bloom or set fruit.
Bloom Date
Some locations have late frosts after a warm period in the spring.
These frosts can destroy the buds on early blooming plant varieties and severely reduce fruit production.
There is also a trade-off between bloom times and chill hours.
Often, especially with fruit trees, late-blooming plants need longer chill hours.
The average chill hours and last frost date for your location will help determine which
plant variety is best.
Tree Size and Longevity
It can be hard to get at the fruit at the top of a 25'
full-sized tree that has not been pruned to control its height.
Some ways to control the size of a fruit tree are to use
(1) genetic dwarf tree varieties which are smaller at maturity;
(2) dwarfing rootstocks; and (3) large containers that limit
the root volume and hence the total size of a tree.
The disadvantage of dwarf varieties is that, for some species,
they may have a shorter life span than full-sized trees.
Pollination
Some fruit plants are self-pollinating and do not need pollen from
another source. Many, however, require a second variety as a source
of pollen so each can pollinate the other.
Still others simply do better with a second plant of the
same variety. A few varieties do not produce pollen at all and are
dependent upon another one that does. Finally, some
species have male and female flowers on separate plants.
To sum up, you may need to purchase two plants rather than one
unless you are sure that you have a self-pollinating variety.
Years Before Fruiting
Another factor to consider when choosing a fruit-bearing plant is the
number of years between planting and when the first fruit will appear.
Generally, plants grown from seed can take the longest time to produce
fruit; plants purchased in five-gallon containers will take less.
Pineapple guava, for example,
can take 10 years from seed to produce its first fruit.
Low Water Plants
Some plants have low water needs when not bearing fruit or growing
roots to support fruit production. These include blackberry, quince,
pineapple guava, walnut, pinyon pine, pistachio, almond, pomegranate,
and jujube.
Read About Your Plant
It is important to have enough information about the plant you want to buy
that you understand selection and cultivation issues thoroughly.
Get a book that describes the plant or do an Internet search and read several web sites.
Be familiar with your location's climate zone, chill hours, and soil.
Choose the microclimate in your yard that is best for the plant.
Understand what plant varieties will do best in your location.
Know what fertilizer to use when and what soil acidity level is needed for each plant.
Planting Trees
Do not plant fruit trees near other trees or large shrubs where their
roots may compete. Keep a minimal distance between trees based on the maximum width
of the larger tree when mature.
Fruit trees require large holes at least 3' deep that drain well and
are filled with properly amended soil.
Watering Fruit Trees
Build a dirt dike outside the drip line of the tree, flood the entire
root zone under the leaf canopy with water, and soak the soil to a 3' depth.
Allow the soil to dry out between waterings. Most fruit trees will need
soaking in this manner once a week while they are fruiting.
Avoid getting water on trunks or leaves.
Culling Excess Fruit
It takes many leaves to support one fruit, and larger fruit require
more leaves. For most prunus species, remove excess small green fruit so that
those remaining are spaced 8" apart. This includes apricot, peach,
nectarine, plum and pluot. Other species may also need green fruit culling
to provide a proper leaf to fruit ratio.
Culling keeps the total fruit load from breaking branches and avoids
undersized fruit.
Reasons to Use Containers
Strawberries and blueberries need moderate to high soil acidity
and consistent moisture. Containers are an easy way to achieve this
environment when local soil is neutral and dry.
Figs have very tasty roots and may need protection from burrowing animals.
A large container is one way to do this, and will also keep the fig
small to minimize frost damage during the winter. One caution: do not
use concrete containers. They are alkaline and inhospitable to
acid-loving plants.
Companion and Antagonist Plants
Antagonist plants are those that should not be near the plant you
are putting in the ground. They may take up the same nutrients as the
desired plant, chemically interfere with its growth, or carry
the same diseases.
Companion plants are those that keep insects away with their scent
or those that attract beneficial insects which prey on plant-destroying
insects.
For example, do not plant blackberry vines where tomatoes, peppers,
potatoes or eggplant have grown or are growing. Pear trees need to
be far away from apple trees, roses, pyracantha and Bermuda grass.
On the other hand, apple trees are helped if you plant chives, marigolds,
nasturtiums and/or onions thickly around them as companions.
Critter Protection
Food crops in Arizona need to be protected from hungry rabbits,
birds, javelina, deer and, in mountains, the occasional bear.
Irrigated trees need to be in an area surrounded by a stout fence
to keep out javelina that like to dig and lie in moist, shaded soil.
Trees should also be draped in large bird nets, reaching to the ground,
with no openings.
At the very least, use 3' high chicken wire to keep rabbits out.
Young rabbits can get through 2" x 4" fencing.
