Pollination Basics
Bees! All tree fruit needs to be pollinated by bees.
If you plan to grow fruit, plan
to deal with bees! While we do not recommend you go into the beekeeping
business, it might be a interesting sideline endeavor, if you have difficulty
finding hives to rent from commercial beekeepers, or your populations of wild
pollinator bees is low. As you may have read, honeybees in particular
are facing great challenges with colony collapse and other diseases and issues.
Proper pollination and, hence, healthy bees are very inter-twined.
Pollination occurs when the blossom is open and the pollen is transferred from
the anthers to the stigmas of the flowers. Since most fruit trees require
cross pollination with a different variety, this pollen transfer does not always
occur in the same flower. Often this transfer is not by a single bee visiting one
variety and them going to another variety, like he "knows" that is his
job. Often is by certain bees in the hive working a single tree over, flying
back to the hive to "unload" their pollen and nectar, and rubbing against their buddies and transferring pollen in
the hive. Then these bees take this pollen to another variety and to other trees. Bees are working
to collect nectar and pollen for their own purposes, and the pollination a by-product that benefits the fruit grower.
Cultured honey bees are
not the only pollinators in the world either! There are many native, wild
bees of species very different from the common honey bee that are often much
more efficient pollinators than honey bees. Learn to respect, maintain and
enhance their
habitats, since the commercial honey bee has many diseases and predator insects
which have been affecting them in the past 15-20 years.
Pollinator Varieties: Many new and beginning fruit growers worry
unduly about proper pollination---which varieties to plant next to others, how
far apart they should be, when they bloom, etc. It really can be simplified more
and made less frustrating.
Apples and Pears: Almost no apple and pear
varieties are self-fruitful. They all require or benefit by cross
pollination with a different variety. Pollinator varieties should
be chosen which bloom close to each other, so that viable pollen can be transferred
by the bees from one variety to the other.
If you are planting a lot of different varieties, relatively
close by each other, then you can worry less about whether or not you are
getting proper pollinators near each other. Trees will usually bloom over a
somewhat extended period
of time, and there may be a lot of overlap. However, if you have large blocks
of single varieties, then consider planting crab apples or other pollinator trees in
the block for better pollination.
Some varieties of apples and pears are sterile and require
pollination from another close-by blooming variety. These usually are
triploid varieties, with extra sets of chromosomes which cause them to not be able
to pollinate other varieties. A couple examples are Mutsu and Stayman.
Peaches and Nectarines are almost always self-fertile and
will pollinate themselves without requiring another variety. There are
very few varieties which require cross-pollination with a different
variety. No pollinators will be required in 99% of peach and nectarine
blocks.
Plums and Prunes: Almost all varieties benefit by
cross-pollination and care needs to be taken to make sure there are enough
pollen sources to insure a good crop. Plums and prunes come in three
classes--- Japanese types, European types, and Hybrid types.
Japanese plums almost always require cross-pollination
with a different Japanese plum. Sometimes a European or Hybrid plum
will suffice, but they can be very particular sometimes, so check with your
nurseryman.
European plums and prunes can often be somewhat
self-fertile, but cross-pollination by a different European or Hybrid
plum is always beneficial.
Hybrid plums are crosses of Japanese and European
plums are usually require some sort of cross-pollination with a suitable
different variety.
Apricots: There are a few apricots which are
self-fruitful. These can be planted without pollinators, but they often
set heavier crops with other pollinator varieties mixed in. For the most
part, plant two or more varieties if possible, and you should have better
pollination and crops.
Sweet Cherries: Prior to the breeding of "self-fertile"
varieties, all sweet cherries
required pollinators. Most varieties STILL far into pollination classes
based on the genes that they carry, and they require certain other varieties to
pollinate with in order to set crops. Most of the old standard varieties, and quite
a few of the new ones, require cross-pollination. Ask you nurseryman
when ordering trees.
Self-fertile sweet cherry varieties are relatively new
developments. They require no other variety to pollinate with, and most
will often make good pollinator varieties for the above ones.
Tart Cherries are usually self-fertile, but a few
varieties really benefit from cross pollination.
As a general rule of thumb, if you have
planted
lots of variety diversity within a class of fruit in the same orchard, then
you will often have adequate pollen sources, but if you have large blocks of
varieties separated by 75-100 feet from each other, then plan to provide pollen
sources within the blocks.
