Pines need plenty of space for their roots

There are two events Saturday that might interest some of you. We are pruning apricots and plums at the University of Nevada Cooperative Extension Master Gardeners Orchard in North Las Vegas with a class starting promptly at 10 a.m. and ending at noon. For more information call the master gardener help line at 257-5555.

The second event is a Winter Holiday Celebration at the Tonopah Community Garden from 4 to 8 p.m. The garden will celebrate with a chili cook-off, sweet potato pie contest, pony rides and holiday spirit. There is a small fee with proceeds helping to support the nonprofit garden. Call the garden at 683-0131 for more information.

Q: I need advice regarding Mondel pines on my property. I have several grouped together. They are in rock mulch, have been fertilized with spikes twice a year and are watered in the summer at the rate of three 15-gallon emitters each for 15 minutes twice daily. They have new growth and are producing cones, but the needles and limbs in the interior trees have died a third of the way up the tree.

There are also two other pines in amended ground with compost and bark mulch that are exhibiting similar stress. All have lost needles and a few small lower limbs each summer for the past give years of their nine-year lives. This summer brought about unusual and much more severe damage. What is the problem and what is the cure?

A: Looking at the pictures you sent I am wondering if they are planted too close together. The closest I would plant pines like these, especially if you plan to keep them for 20-plus years, is about 30 to 40 feet apart.

Your trees are growing well at the tops in full sun and poorly lower down where the branches receive more shade. If trees are planted closely so that they shade each other, then the growth will be forced toward the light at the expense of lower, shaded limbs.

When this happens we see lots of growth at the top but the lower shaded limbs lose needles and even die back. Because these plants do well here with few disease and insect problems I tend to think of shading as the reason.

The other reason for losing needles is drought, but the tops look like the needles are being retained. It is normal for pines to lose needles inside where wood is more than three years old. When needles are lost on wood younger than this, there is a problem.

Q: My wife and I are looking to plant a pluot tree in our yard and looking for some advice on what types work best in the Las Vegas Valley. Our house is near downtown, so it's low in the valley and there are few frost hours. We are looking to place an order for bare-root trees with a nursery this week or soon for January planting. Any advice about which pluot you can give us would be greatly appreciated.

A: Pluots are interspecific hybrids of apricot and plum. In other words, a plant hybridizer by the name of Floyd Zaiger began crossing apricots and plums and developed fruit the world has never seen before including pluots, plumcots, apriums and the like.

I would put in Flavor Supreme, Flavor Queen, Flavor King and Emerald Beauty plum (not a pluot but a very good Zaiger genetics development). Santa Rosa plum is a good pollenizer for most pluots.

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 morrisr@unce.unr.edu.