GARDENING: Vine growth can diminish size of grapes

Question: This year my grape leaves are almost green after putting the iron chelate on you recommended this spring. Now I have some other problems to solve. First the grape branches are not growing much. Mostly they are 2 feet long or less. I give them water 1 time per week for 10 minutes, 3 feet from the trunk. I give one cup per plant of the following fertilizer two times per year; ammonium sulfate, sulfur plus Epsom salts and super phosphate all mixed together.

Answer: You want to find a compromise between growth of the vines and growth of the fruit. Excessive vine growth will diminish the size of the grapes. You want enough leaves to cover the bunches to prevent sun damage and enough leaves to make sugars and other carbohydrates to enlarge and sweeten the grapes. Also pinching the ends of the bunches and removing that "tail" on the bunch will, when the fruit is pea-sized, make the individual grapes larger.

You might want to try some foliar spraying next spring as the new shoots are emerging. We used foliar applied fertilizer on our grapes and fruit trees at the research center that were not performing well and had very good luck. There are several good fertilizers out there you can use as a foliar spray. We happen to use Miracle Gro but there are Peters and Rapid Gro available as well. They all will do very well to stimulate new growth.

I would still make your soil applications but supplement the soil applications with two or three weeks of foliar sprays when the leaves emerge in the spring. When air temperatures reach about 90, terminate your foliar sprays.

Q: I have nectarines and peaches with this clear liquid like glue coming from the skin. I don't see any damage to the skin when I remove it.

A: Unlike most of our peaches, nectarines damage easily in our climate. This sap coming from the skin is probably due to a small hole punctured through the skin that you can't see. The other possibility is peach twig borer. Peach twig borer can lay their eggs on the surface of both peaches and nectarines. The very tiny peach twig larvae, when they emerge from the eggs and penetrate the skin, can allow sap from the fruit to emerge. This sap can ooze in a clear curly-cue "thread" from the skin. There are some things you can do before it gets into the fruit if you have peach twig borer but not afterwards.

Q: We recently purchased two magnolia trees. Can you give us some watering and fertilizer tips for these trees? We have been deep watering them twice a week and have used Miracle Grow (acid) on them. How often do you suggest fertilizing and with what type of fertilizer?

A: Magnolia trees will have a struggle here in our climate and typically we have not had much success for too many years after they have been planted.

The worst place to put them would be in a south or western exposure to the sun, in a desert landscape under drip irrigation. They would be nearly impossible to manage and perform well under these conditions. What they do prefer is an organic soil with moderately high light exposures. So typically they have performed best in our climate where they can get some protection from winds and the hot, late afternoon sun.

If this were me I would plant them in a north or eastern exposure, amending the soil with good soil amendments right from the start. Make sure you water the trees deeply after planting to help remove soil salts if this is a newly planted area. Mulch them (surface applied organic matter over the roots) with two to thee inches of organic mulch keeping the mulch a few inches from the trunk. Water them in such a way that the area under the canopy of the tree is wetted to a depth of two feet about twice a week this time of year. Fertilize them in the late winter or very early spring with a fertilizer formulated for trees and shrubs applied to the root area. Follow this up with your foliar applied fertilizers, such as Miracle Gro, when leaves emerge in the spring.

They do not need frequent fertilization. You might also try fertilizing them with a foliar spray again in late September or early October. I only recommend this on trees with a good history of tolerance to our winter temperatures. Borderline trees that might be damaged by freezing temperatures should not receive any fertilizer after July 1.

Q: Last year I had two healthy Windmill palms in my front yard. This year one has started to die. What can I do?

A: Normally windmill palms do fairly well here if you are willing to accept them as less than perfect. They don't look like they do in milder climates like in Southern California, but they do tolerate many of our extremes and they are a palm, although slow growing, that remains in scale with most residential landscapes over the years.

They always do best when planted in areas of the yard that do not have the desert extremes in heat, wind, and light. So planting them where they can get a little protection from the late afternoon sun and avoid extreme desert landscapes (cactus and rock), but rather in an "oasis" area, would see their best performance here.

They need frequent irrigations to look good. Although they tolerate a lack of water -- because they are somewhat drought tolerant -- they will not look good under these conditions.

Usual symptoms of under watering would be the development of small, scorched leaves that may be distorted. If this occurs, deep watering twice a week will cause them to rebound.

Q: We bought two five-gallon sago palms a couple of years ago and planted them in containers. We transplanted them last year after they had grown quite a bit and now the fronds are looking a little on the yellow side on one of the palms. What is causing this and what do you suggest we do to make it better?

A: My gut reaction is that there are possibly three reasons for this. Remember that sago palms are not a desert plant. So, for this reason, they will do best in places where it is not like a desert. They prefer an "oasis" area rather than the stark desert.

First, many times when sagos are transplanted you will see some fronds dying back. This may be just "transplant shock," the above ground reaction to the loss in root system during transplanting, or moving from one location where it had made adjustments to an entirely new location. This can be fairly typical when going from one type of exposure to an entirely different growing condition particularly if the transplanting is not done under the best conditions -- early morning in the summers, left in the container too long, planted quickly when transferring it to the ground, planting into a dry hole, etc.

The other could be an exposure that is just too fully exposed to the sun. The worst location to plant them would be south, west or southwesterly particularly in a desert landscape. They could use some shade in the afternoons and organic mulches that will decompose on the soil surface under their canopy. If this is an isolated one or two fronds I would guess it is transplant shock. If this is a general "bronzing" of the fronds, then it is probably too much exposure to direct sunlight.

Bob Morris is a horticulture specialist with the University of Nevada Cooperative Extension.


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