Pear tree pollination: It’s all about the bees

: I bought a Monterey pear tree in California a couple of years ago. The tree has had blossoms but no fruit. Why will this tree not produce fruit? Otherwise, the tree looks healthy. I cannot find very much information about this tree.

A: I also know very little about this tree so I had to do a bit of digging. This tree was propagated from a pear tree planted at Mission San Juan Bautista not too far from Monterey, Calif., and in between Salinas and Hollister.

The original parent tree was probably planted sometime around the beginning of the 1800s. The one surviving pear tree from the original plantings was propagated and named the Monterey pear for marketing reasons. This could be done unofficially because the tree’s parentage is unknown, probably coming from European pears brought to this continent centuries ago. This is not a fruitless, ornamental pear; it is a fruit-bearing tree.

All pear trees require a pollinator tree. To be a pollinator, the blossoms must be open at the same time and the pollen must be compatible with the pear tree producing the fruit.

Pear tree varieties open their flowers at different times from each other. For example, the European pear variety called Hood has blossoms that open quite a bit earlier than Bartlett pear. Hood will not pollinate Bartlett and vice versa because the flowers are not open at the same time. Just having another pear in the vicinity is not enough and you cannot assume that any old pear trees will pollinate each other.

The majority of pear tree pollination results from the activities of bees. If there are no bees present or if the weather was cold or overcast during the time the flowers were open, it is possible that bees were not active and no pollination occurred. If there are no other pear blossoms open at the time your tree is flowering, pollination will not occur.

Also, the tree must be old enough to bear fruit. In some older and less precocious varieties this could take as many as six or more years. Fruit bearing requires that the tree have fruit-bearing spurs. If this pear tree has blossoms on it, it probably has fruit spurs.

If this pear tree has blossoms that open very early in the season like the Hood, it is possible to lose the fruit due to late freezes. This would have been the case during the last couple of years in the valley’s outlying areas. This spring, however, we did not have any late freezes after about mid-March.

Chances are, there is no pollinator tree in close vicinity to this pear or the weather did not permit much bee activity at the time of bloom. Give it another chance next year.

Q: How do you get rid of pigeons in the front yard? We just seeded it.

Also our sprinkler system was working for awhile and now it is not working. We had to change the solenoids because they were rusted. The system is getting power. I programmed it but it just doesn’t start or run, or it says it is running but I don’t see any water.

A: I don’t know of a good or easy way to keep pigeons from eating seed except to apply a lot more seed than is needed, frighten them away or give them something else to eat and cover the seeded area with a topdressing so it’s hard for them to find the seed.

Rusty solenoids usually means water is getting in the irrigation boxes right after an irrigation or the valves and the solenoids are being covered with dirt and getting wet. You may not see the water in the irrigation box because they usually drain quite rapidly. You would have to check immediately after the water shuts off.

It is a good idea to remove soil from underneath the irrigation valve to about 6 inches deep and put coarse gravel beneath it so that the water drains away from the valve.

If the controller says the valve should be on but water is not flowing, there are a couple of things that you can do.

The most common mistake is that the water is turned off somewhere and not reaching the valve. Make sure the water is turned on and reaching the valve.

The second mistake people make is not having a secure connection between the irrigation controller wire and the wires coming from the solenoid. These wires must be clean and twisted together tightly inside a waterproof connector otherwise they will corrode and fail to open the valve.

A third mistake is using electrical wire connectors or even electrical tape not intended for wet locations. Use electrical wire connectors manufactured for wet locations. These types of connectors are more expensive but they create a waterproof connection between the controller wire and the wires from the solenoids.

If you are using electrical connectors intended for dry locations, remove them, recut and strip the wires and make new clean connections with waterproof connectors.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by e-mail at extremehort@aol.com.