AVAILABLE POLLENS

Almond • Apple • Apricot • Avocado • Cherry • Hazelnut • Kiwifruit • Pear • Pecan • Pistachio • Plum • Pluot

Almond (Prunus amygdalas)
• Almonds are grown in Mediterranean climates all around the world. Prominent growing regions include California, Australia, Spain, Chile, etc.
• Almonds bloom in late winter to early spring. In California, typical bloom period ranges from early February to early March. Almonds are an insect-pollinated species, with wind playing very little if any role in pollen transfer.
• Growers of almonds are among the major users of controlled pollination.
• Almonds are self-incompatible, requiring cross-pollination in order to set a crop.

Apple (Malus domesticus)
• Apples are grown worldwide, and have been commercially cultivated for thousands of years.
• Apples bloom in the Pacific Northwest region of the US from mid-April to early May.
• Apples are pome fruits with multiple carpels (areas where seeds will develop). As a multi-seeded species, imperfect pollination can result in undeveloped carpels causing misshapen or small fruit.
• Self-incompatibility exists in Apples making cross-pollination necessary.

Apricot (Prunus armeniaca)
• Apricots are closely related to cherry, peach, nectarine, plum and almond. They originated in China, and thrive in a Mediterranean type climate, like central California.
• While many varieties can over-set requiring extensive thinning to reduce crop load, other varieties can have difficulty achieving sufficient pollination naturally, and can benefit from supplemental, manually-applied pollen to set commercial crops.
• Most Apricot cultivars are self-infertile, as with other prunus species.
• Apricots are insect pollinated, with wind responsible for little or no pollen transfer from anther to stigma.

Avocado (Persea americana)
• Avocados are a subtropical species and are cultivated in the southern US through Mexico and South America. The unique flowering habit of the avocado, coupled with its sensitivity to cold temperatures and the dehydrating effects of wind create serious challenges to pollination and fruit set. The high market value of this crop motivates considerable effort from growers to ensure large crops – including the use of controlled pollination.
• Avocados varieties fall into 2 distinct groups:

• Type A varieties: Haas, Gwen, Pinkerton, Reed, Anaheim, Lamb Hass
• Type B varieties: Fuerte, Zutano, Bacon, Whitsell, SirPrize

Cherry (Sweet Cherry, Prunus avium)
• Sweet cherries are cultivated around the world with Turkey and the USA ranking first and second in world production. In South America, Chile is the largest sweet cherry producer by far.
• Cherries are mature and ready to harvest within 100 days after pollination.
• Rain before harvest is a common cause for crop failure in cherries, which can occur in 2 out of 5 growing seasons.
• With the prospect for loss due to rain, cherry growers are eager to make the very most of each growing season knowing that over the life of an orchard, a significant percentage of crops will be lost.
• Controlled pollination in cherries is common in all regions where cherries are grown around the world.
• Cherries are insect pollinated, and are self-incompatible, requiring cross pollination to set commercial crops.

Hazelnut (Corylus various species)
• Hazelnuts are used to make Nutella. What more do you need to know?
• Hazelnut (or Filbert) trees have one of the more peculiar pollination habits of any commercially grown crop: Pollen is shed in winter; is captured by the stigma of the female plant; and is then held dormant for roughly 2 months before it begins to germinate a pollen tube and complete fertilization.
• 99% of the US hazelnut crop is grown in Oregon. But areas in Washington state are seeing an increase in plantings over the last several years. US production represents less than 5% of hazelnut production worldwide.
• Growers are finding that supplementing pollen during the critical phase, can increase yields in this

Kiwifruit (Actinidia chinensis, Actinidia. deliciosa)
• Kiwifruit originally exported from China in the 1800’s as the ‘Chinese Gooseberry’, but was brought to international popularity by New Zealand.
• Two primary groups of kiwifruit are common: fuzzy green kiwis (A. deliciosa) and smooth, gold kiwis (A. chinensis). Hardy Kiwi Berry (A. arguta) is gaining popularity as a specialty fruit, and is grown in cooler climates like central Oregon in the USA.
• Kiwifruit is a dioecious species, meaning plants are either male or female. Pollen must be transferred from a male plant to pollinate flowers on the female plant to make viable fruit.
• Kiwi orchards most commonly grown on a pergola training system with the vines growing overhead above the space between tree rows. Fruit is harvested from below.
• Kiwi flowers produce no nectar as a lure for pollinating insect activity. This makes the kiwi flower a relatively unattractive target for bee foraging activity, and can result in suboptimal pollination. Given the high seed count per fruit (1,000 plus), the crop has a high demand for pollen. Poor pollination in kiwifruit can result in misshapen or small fruit, reducing commercial value of the crop considerably, making controlled pollination in kiwifruit a standard cultural practice around the world.

Pear (Pyrus communis), Asian Pear (Pyrus pyrifolia)
• Pear typically refers to European pear, with Asian pear occupying its own category.
• Like apple, pears are pome fruits and with multiple carpals. Each carpel will form house a seed if properly pollinated. Pears are notoriously undesirable as a nectar source for honey bees, with a resulting reduction in bee visits and pollen transfer. Poor pollination can result in misshapen or small fruit, as with apple.
• The Asian pear (Apple pear or Nashi) is similar to the European pear with respect to pollination, and is the author’s single most favorite piece of fruit.

Pecan (Carya illinoinensis)
• Pecan acreage in the US is concentrated in the southern states like Georgia, but is also found in pockets in other growing regions like California.
• Pecans are wind-pollinated. Unlike pistachio, male and female flowers are both found on the same plant. But bloom timing between the two flowers is almost always out of sync, making at least two cultivars necessary in an orchard to ensure good pollination.
• Poor coordination even between cultivars is common, and can result in poor pollination. This can be corrected using supplemental, manually-applied pollen.
• Pecan trees can grow up to 100 feet tall, and can produce for up to 300 years.

Pistachio (Pistacia vera)
• Pistachio originates in the middle east in warm and dry climates. It is believed that pistachio trees can live for in excess of 300 years. In fact, there is a pistachio tree in Israel roughly 450 years old. Its trunk has a diameter of over 6 ft, and it is almost 60 ft tall. It is considered one of the most impressive trees in Israel.
• It is a wind pollinated, dioecious species. Male and female plants are selected based mainly on bloom timing to ensure that females are ready to receive pollen when it is being released by the males.
• Lack of bloom timing coordination between males and females is common, and can be exacerbated during years with low chill hours. This can result in suboptimal pollination and nut set, contributing to low yields.
• It’s wind-pollinated habit makes pistachio like other wind-pollinated species a natural fit for supplemental, manually-applied pollen.

Plum (Prunus various species)
• Commercially-grown plums fall into two basic categories: Asian and European species.
• Common prune cultivars are European species. Cross pollination is required in plums (as with all Prunus species) but pollination cannot take place between Asian and European cultivars.
• Plums typically bloom in late Winter, making them susceptible to the effects of low temps and inclement weather typical to this time of year. This can make pollination challenging.
• Since plum pollen works to pollinate interspecific hybrids like pluot, these species can be mentioned here. Some pluot varieties are notoriously difficult to adequately pollinate, resulting in abysmal fruit set. For these difficult to set cultivars, controlled pollination can be the key to commercially viable fruit set.