Avocado adventures Essay

“I love that monster, even though it keeps us from living a
normal life.” So writes Al Kray about his bearing avocado tree in
Glendale, California. Other home growers might agree: when an avaocado
tree rewards you with a hefty crop, it’s easy to overlook the
tree’s faults: large size, temperamental bloom habit, constant leaf
drop, and a dense, shade-casting canopy that makes for difficult
gardening below.



If you’re growing an avocado tree now or are planning to plant
one, here’s advice on how to keep it happy, how to live with its
habits, and how to harvest the fruit.



More than 300 readers contributed to this report; they wrote us in
response to a query in Sunset. Some, like Dr. Baldwin Lamson (pictured
on opposite page) and the Joe Muellers (above left), started trees as
nursery-grown plants; Dr. Lamson now grows 28 trees-eight varieties–on
a terraced, 1/2-acre hillside. Many, like john Eells (left), inherited
their trees from previous owners. Still others, like Mrs. Roland Manning
(above), started trees by sprouting seeds in glasses of water in the
kitchen.



Mid-March is the best time to plant an avocado tree in mild, nearly
frost-free climates (see the map on page 121 for areas where avocados
grow best); the longer the tree has to get established, the better it
will be able to withstand the first winter. If frost is still possible
in your area this month, your winters are probably too cold for
avocados. Start with the right variety


The best variety for your climate and site can improve your chances
for a bearing tree. If in doubt, your extension service.



At left, we show seven commonly grown varieties. If you inherited
your tree, the photograph can help you identify it.



Guatemalan types are the most frost-tender; they’re widely
grown only in the most frost-tree areas, including mildest parts of
Southern California.



Mexican types are hardiest but smaller and thin-skinned.
They’re best for lower, colder inland valleys and temperate areas
of northern California.



‘Fuerte’, a hybrid midway in hardiness (about like a
lemon tree), is widely grown in slightly colder ares of inland Southern
California and in the San Francisco Bay Area. Once popular
commercially, it’s touchy about bearing fruit in areas where early
flowers are subject to frost.



Where garden space is at a premium, try a dwarf or semidwarf
variety, such as ‘Littlecado’, ‘Gen’, or
‘Whitsell’.



Nurseries sell trees in 5-gallon cans for $14 to $20, in 15-gallon
cans for $30 to $65. Plant in well-drained soil in full sun, in a spot
protected from wind. Seedlings: a gamble, but you may get lucky



If pit-started trees bear at all, their fruit usually differs in
size, shape, and quality from the mother plant. Our readers report
varying degrees of success with them, from excellent (“My pride and
joy is 31 years old and consistently produces tasty, black-skinned
avocados”) to s-so (“I’m not really crazy about the
fruit”) to no fruit at all (“After 20 years, my seedling
remains a lush, healthy ornamental”).



If you have space to spare, you might try growing a seedling. To
reduce the gamble, you can graft a bearing avocado onto the seedling
rootstock, but this takes patience and some know-how; only two out of
nine readers who tried it reported success.



“If you want to harvest avocado of predictable quality,”
writes Frank Ishihara of Alta Loma, “you can’t make a better
investment than a nursery plant.” Secrets of success: how to water,
fertilize



Avocado trees can’t take drought, but they don’t like wet
feet either. One rule of thumb: water whenever the soil is dry 18 to 22
inches below the surface (check at the drip line with a soil auger). For
mature trees in well-drained soils, that usually means watering every
two to four weeks in summer, more often in hot, dry, windy weather.
Frequent light waterings are best where soil is shallow, since root
systems are most likely in the first foot of soil. Deeper watering is
best in deep, sandy loam–the best soil for avocados–where roots can be
2 to 3 feet deep. A heavy watering about every fourth time helps flush
salts from the soil.


Rotating sprinklers and drip emitters work well. Most Sunset
readers prefer slow soaking with a hose around the drip line. One
reader soaks the root zone under his tree one quadrant per weekend
(always the same section on the same Saturday of the month) for an hour
or two, depending on the weather.



IF you build a watering basin around the drip line, knock it down
before rains come to keep water from building up.



Mature bearing avocado trees grown by Sunset readers get every kind
of feeding regimen: no fertilizing at all, occasional fertilizing, or
light applications as often as once a month during growing season.



Nitrogen is the chief nutrient avocado trees need; mature trees
appreciate about 1 pound per year. Some gardeners use ammonium sulfate.
A complete fertilizer with an NPK number of about 10-8-6 (sometimes sold
as “citrus and avocado food”) is another popular kind; a
regimen of 3 to 5 pounds per mature tree applied two times a year
between February and October equals about 1 pound of actual nitrogen per
year. Young, nonbearing trees get off to a good start with much less:
about 1 teaspoon every second or third watering the first year,
following package directions. If pruning is necessary



Mature avocado trees need little or no pruning. Left on their own,
however, some varieties grow into shapeless mounds of foliage; others
shoot skyward and dangle their crops mostly out of reach.



Best time for shaping and developing a good branch structure is
when a tree is young. To induce bushiness in upright growers, pinch out
terminal buds after each growth spurt for the first few years.



Once trees are established, most Sunset readers prune them only to
keep stray limbs out of their neighbor’s yard or below telephone
wires, to open up the canopy to prevent wind damage, or to lighten
excessively heavy limbs.



If you prune, make cuts as close to a main branch as possible, and
remove as little green wod and as few leaves as possible. Before you
prune off lower branches to expose the sunburn-prone trunk, make sure
the leaf canopy is dense enough to shade it, or coat the trunk with
white water-base paint. Be consistent about pruning top growth of
upright kinds, or it will grow right back.



Avocado trees are relatively trouble-free in home gardens. For
some problems encountered by Sunset readers–and what to do about
them–see page 232.



If you live outside the avocado belt, cover trees the first year
with burlap (not touching foliage), if necessary, to protect them from
hottest sun and frost. A word about pollination


If there are bearing trees in your neighborhood, you probably
don’t need to worry about pollination, and you may get a better
crop: one reader’s tree bears its heaviest crop on the side facing
his neighbor’s tree, 20 feet away.



Weather must be warm (above 60[deg.] or so) when flowers form, or
fruit won’t set. For more abut pollination, see page 232. When
and how to harvest



On the tree, avocados don’t soften until past their prime, so
it’s difficult to tell when to pick them. Some readers go by frut
appearance: “The skin of ‘Mexicola’ gets a frosty look,
and the fruit comes away from the stem easily.” Or by sound:
“Shake a ripe ‘Duke’ and the seed inside rattles.”
Others wait for local critters to give them a clue: “When I spot
raccoons washing avocados in my pool in the dead of night, I know
it’s time to pick.”



But there are other clues: as they mature, dark-skinned kinds turn
from green to dark; green-skinned kinds lose their shine. Stems turn
yellowish on some kinds. If you cut an immature avocado in half, the
seed coat looks thick and white; in a mature fruit, it’s
papery-thin and dark brown.



Best way to tell if it’s harvest time is to pick a large
avocado and let it soften indoors. If the fruit is mature enough to
pick, it will soften in about 5 to 10 days; if immature, it will shrivel
(wait a week and try again).



Often the only way you can harvest the upper reaches of a tall tree
is with a pole picker (see cover photograph). Sunset readers use
everything from a polemounted 1-pound coffee can with a V cut in the rim
to a swimming pool brush pole with a three-prong cultivator attached.
(Cutting the stem is better than pulling it; leave a little stem
“button” attached.) A few readers report success with the
team “cut-and-catch” method: one person mans the pole picker,
while the other catches the avocados in a net bag.



You can buy pole pickers with cutting devices attached and long
cords for operating them; some come with canvas bags attached to catch
the fruit.



Even with a ladder a pole picker, you may have to wait for gravity
or squirrels to harvest crops from tallest trees. Some tree services
will pick fruit from very tall trees, but it’s expensive (about $60
per hour for a two-person crew). If you grow a summer-bearing variety,
some tree services will pick highest avocados and lightly prune or shape
the tree at the same time. (Pruning in late fall and winter stimulates
new growth that’s most susceptible to frost damage.)



Until late in the season, most back-yard growers harvest only what
they use in a week or so. Some varieties can stay on the tree up to
five or six months; others need harvesting within two to three months.
What to do with leaf drop



A few Sunset readers rake fallen leaves into a uniform layer
beneath the tree for mulch; for a neater pile, run over it with a rotary
lawn mower, or confine fallen leaves with a low wire fence around the
drip line. You can make compost below the tree: water and turn leaves
occasionally, then rake them up each fall and dig them into garden beds.



If piles of leaves invite tree rats in your area, compost the
leaves or send them out with the trash. Gardening under avocado trees



Some fastidious gardeners prefer to grow things under their avocado
trees. Bernice Mattern of San Jose (see photograph above) isn’t
concerned about disturbing the shallow roots of her 35-year-old
‘Fuerte’ when she plants: “I poke around with a shovel
until I find a place where no big roots are, then I dig.”



If you’d rather not risk injuring shallow roots, confine
plants to posts clustered around the tree’s base, or to baskets
hung from the tree’s widest, strongest limbs.



Two readers nurture thriving St. Augustine lawns below avocado
trees, lightly pruning their canopies so the grass gets some filtered
sun.



One reader finds the concrete patio encircling his tree to the drip
line makes clean-up easy, but watering and fertilizing tough. He feeds
and waters the tree through 15-inch holes and waters into the soil every
30 inches around the patio edges.