Early fruit slows growth of young trees

I would like to thank readers for sending in their comments regarding methods for keeping birds away from fruit. It is apparent that there are a lot of good ideas out there but that research has not supported much beyond the use of netting. I wish I could post all of the comments.

In commercial orchards, the use of shiny, reflective tape, other shiny objects and noise generators is quite common. It is much easier in orchards that only have a few types of fruit since they mature all at once and the sheer volume is too much even for the birds. Another method is to harvest fruit a bit early and not allow it to fully ripen on the tree.

In the University of Nevada Cooperative Extension Master Gardener Orchard in North Las Vegas we are using sound devices that make noises like distressed birds and hawks as well as dangling fishing line. We don’t initiate the sound devices until just before harvest otherwise the birds get used to it. Most of the methods we have tried are semieffective at best.

If you enjoy wine, good food and the outdoors, you might want to mark your calendar. Saturday from 11 a.m-3 p.m. is the second annual Vino in the Orchard day. This year, besides free wine tastings, there’ll be other free food available, tours of the orchard and classes on growing wine grapes as well as children’s activities.

Tickets are $15 for adults; children are free. They can be purchased at Vino 100, 7220 W. Azure Drive or placed on will call to be picked up at the orchard that day by calling 734-8466. Part of the proceeds will help support activities at the orchard.

Q: Last summer, I planted two small pomegranate trees. This spring, they are about 3 feet tall, have leafed out nicely and now are blooming and setting fruit. The limbs are very small, about the diameter of a matchstick, and I’m afraid they won’t be able to support the fruit. Should I pick the small fruit that is setting as well as the blossoms to give the plant some relief or should I try to provide some support for the fruit and let the plant bear all that is setting?

A: Any fruit that you leave on the tree will slow down the growth of the plant. If you slow down the plant’s growth, it will take longer for it to begin producing larger quantities of fruit.

This is really your call and it depends on what you value. If you value getting some early fruit and don’t mind that the tree won’t get large quickly, then leave some fruit on the tree and enjoy it. If you don’t mind sacrificing some fruit now, realizing the tree will become larger more quickly and produce larger amounts of fruit earlier, then remove the fruit as soon as it appears — but enjoy the flowers.

Any part of a plant that is growing is using large amounts of the plant’s energy. New shoot growth and new and enlarging fruit growth consume large amounts of energy. If the fruit is removed when it is very young, the energy that would have gone into the fruit will be diverted into new growth.

The same is true of new growth. If you can determine what growth you plan to keep and what you will eventually get rid of, then light pruning during the growing season can provide big benefits toward increasing the size of your plants more quickly. Light, selective pruning forces energy into the remaining growth.

It is important to remember that the earlier you remove unwanted new growth, whether it is fruit or new shoots, the faster your plants will increase in size. When you are removing larger fruit and older woody growth, the energy used by the plant to achieve this growth also will be removed. In other words, removing this older growth and not utilizing it in some way is wasteful. This is great stuff for use in composts rather than sending to a landfill.

One more precaution about pruning during the growing season. You should exercise some caution when pruning during this time because of our very high light intensities and the potential for sunburn. You always want to leave some growth behind to shade branches and stems from high-intensity sunlight.

This is very critical for trees that have very thin bark, including most of the stone fruits, such as apricots and peaches. Apples also can get sun damage if too much leaf shading is removed. Palo verde will sunburn if pruned severely, which also leads to invasion by boring insects.

Q: Around July of last year, we had two flowering plums with red leaves planted. Well, now the flowers are gone but there are little red plums about the size of a cherry on the trees. We took one off and opened a portion. It smelled like a plum and we want to know if they are or will be edible.

A: These trees are usually purchased for their looks rather than fruit; they are called flowering plums, an ornamental type of fruit tree rather than a tree grown for its fruit. They also are sometimes referred to as cherry plums since they produce small, cherry-sized edible fruit.

Two of the most common ornamental flowering plums with purple leaves are Thundercloud and Krauter’s Vesuvius. The Krauter’s Vesuvius, although nearly identical in appearance to Thundercloud, is probably a better selection for our soils. These ornamental fruit trees may, at times, produce large amounts of fruit. Since it blooms quite early, late spring freezes may reduce or eliminate fruit on the tree. Most of the fruit from ornamental flowering plums is tart but suitable for making jams and jellies.

Flowering plums are not typically long lived trees. A 20-year-old ornamental flowering plum reaching perhaps 20-25 feet tall would be considered an old tree. Our climate is slightly out of the preferred range for this tree. They do struggle a bit here. Placing these trees with rock mulches would be a mistake; they prefer to be in soils with organic matter in them.

They typically get chlorotic about five years after planting and their branches begin dying back and may get borers. Also growing these trees on the south or west side of a building with reflected light and heat will be too much for them. They are better placed on the east or north sides of buildings.

These trees are susceptible to root rot if placed in soils that do not drain water easily or if they are watered too frequently. Because they are stone fruits, they are susceptible to boring insects, branch dieback and oozing sap. The oozing sap may or may not be related to boring insects. Just because a tree is losing sap is not a reason to assume it has borers. There are sometimes physiological reasons for sap oozing from trees. Sometimes heat stress is enough to cause it, particularly on plums.

Another common problem of this tree is iron chlorosis. When most green-leafed trees get iron chlorosis, their leaves will turn yellow. When plants have red or purple leaves, iron chlorosis appears as pink leaves.

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.