Growing kiwi

I have two very healthy kiwi vines, one male and one female. My female plant is flowering profusely right now, but there are no flowers on the male plant. I have had the plants for about 15 years or more and have never had fruit. They do not seem to bloom at the same time. I have just never bothered about it before, but this year I thought I would check out some options.

Any resources regarding hand pollination (both instructions and local suppliers) would be really helpful.

Oregon State University Extension’s guide, Growing Kiwifruit by Bernadine Strik (2005), has information about pollination:

“For fruit to be produced, male and female vines must be present in a block and must flower at the same time. Male flowers produce viable pollen for only the first 2 to 3 days after opening. However, female flowers are receptive to pollen for 7 to 9 days after opening, even when the petals have started falling.

“Pollination is extremely important in kiwifruit production. Large fruit contain 1,000 to 1,400 seeds (research on Hayward). If pollination is poor, fruit will have indentations (narrow valleys) on one side or be non-uniform in shape. If you cut through these fruit, you will find no seeds in these areas.

“Kiwifruit flowers are pollinated mainly by insects, although wind may play a minor role. Honey bees are the main pollinator used in kiwifruit vineyards. Kiwifruit flowers do not produce nectar and are relatively unattractive to bees. About three to four hives per acre are needed to adequately pollinate kiwifruit. Place these in the vineyard no sooner than 10 percent bloom of the female vines.

“In some years, you may have no male vines in flower as a result of winter injury to male plants (they are less hardy than the females). In this case, no naturally produced pollen will be available. To get a crop, the females will have to be pollinated artificially. Call your county Extension agent for more information on sources of pollen and methods of artificial pollination.”

(Note the section on Hardy Kiwi which are different than Fuzzy Kiwi.)

You might also find this article from The Olympian newspaper (May 16, 2009) of interest. It features kiwi growers Hildegard Hendrickson and ‘KiwiBob’ Glanzman, and discusses hand pollination, general care, pruning and training.

Actinidia, Pollination

attracting pollinating insects

What flowering plants should I place near my two blueberry plants in containers on my driveway that might attract the kinds of insects to maximize pollination of the blueberry plants?

Almost any plant that flowers at the same time your blueberry plants flower will help attract pollinating insects. This could be anything from apples to clematis to more blueberries. The Xerces Society (a Portland-based conservation organization) has published this useful fact sheet about choosing plants to help our native bees.

on monoecious plants and bisexual flowers

My neighbor says his Deodar cedar tree is bisexual, and it’s the male cones that are making so much pollen this October. He seemed to be saying this was unusual, and that not all cedar trees were like this, with both male and female cones. What’s the story?

Cedrus deodara is monoecious, which means that an individual tree will bear separate and unisexual male and female flowers. If the tree had bisexual flowers, each flower would be ‘complete’ and ‘perfect,’ that is, with male stamens and female pistil in each flower. So it’s clearer to call the tree monoecious than to say it is bisexual. According to Wayne’s Word: An Online Textbook of Natural History, “about 90 percent of all flowering plants have bisexual flowers with both male (stamen) and female (pistil) sex organs. The remaining 10 percent have unisexual male and female flowers on the same plant (monoecious species) or male and female flowers on separate plants (dioecious species).”

Most conifers (like true cedar) are monoecious. The male pollen cones are 2 to 3 inches long by October, and are found in great number on the lower parts of the tree. Female flowers are tiny, and usually found high up in the tree. Female seed cones take two years to mature. You might wonder how pollination can take place if the female flowers are up high and the pollen is down low. Conifer pollen is wind-dispersed, so it might seem arduous for it to reach the female flowers up above. However, if you consider the geographic origins of the true cedars, you will notice that Deodar cedar is also called Himalayan cedar and like the cedar of Lebanon (C. libani) and the Atlas cedar (C. atlantica), its native range is mountainous. Imagine cedars growing on a sloping mountainside, and you can easily picture the pollen drifting downward to female flowers on the trees below.

grape vine producing uneven fruit sets

What causes some grapes to get to normal size and others to stay small? This is on a Concord vine about 7-8 years old.

Some varieties of grape produce naturally straggly clusters of fruit. According to The Grape Grower: A Guide to Organic Viticulture by Lon Rombough (Chelsea Green, 2002), Concord has a tendency to ripen unevenly in hot climates (such as the mid-South), but he doesn’t note straggly clusters as a characteristic of this variety. That makes me think the uneven size of your fruit is more to do with pollination. See the following, from Oregon State University Extension, which suggests that a cool, wet spell around the time of bloom can interfere with pollination and result in large numbers of unset berries. Rain, which also inhibits pollination, can also be a factor in poor fruit set.

There are other possible reasons for the uneven fruit set. If you are growing a variety of grape which is not ideally suited to your climate, or if the soil is overly rich or overly fertilized, you may not get abundant fruit.