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Wednesday, November 23, 2016

Stay With Hot Weather Wine Grapes in Las Vegas

Q. I'm getting ready to place an order for wine grape plants. Currently I have 25 plants that are 3+ years old. These consist of mainly Zinfandels and Cabernets with a few Merlots. Can you give me any info on nurseries to deal with and type of plants I may need?

A. You can wait a bit to make a wine grape order unless you tell them not to ship until late February or March. I want to avoid freezes after planting.

Basically stick with the so-called hot climate grapes. Summer Muscat is a good one for you. Others to look at include Syrah (Shiraz), Petit Syrah, Barberra, Grenache, Sangiovese, Malbec, Tempranillo,
Zinfandel growing in Las Vegas in trials 2007-2011
Pinot Noir growing in Las Vegas. Not a grape I would normally recommend here but I wanted it so I grew it and it did surprisingly well
Sauvignion Blanc growing in Las Vegas trials
Alicante Bouschet in veraison growing in Las Vegas trials. Another problem with hot weather is uneven ripening of the grapes due to hot weather and warm nights
Viognier to get you started. Look closely at Malbec if you like Malbec wines. Syrah is always a good one for blending as well as Barberra, Grenache, Merlot, Petit Syrah, Zinfandel and Primativo which some claim is a Zinfandel.

Should I Put a Sheet on my Veggies This Winter?

Q. I have vegetable garden. Do I have to cover with a sheet if it freezes?
A. It depends on the vegetables and the site. Vegetable gardens located in warm areas of the yard with reflected heat and very little wind are much warmer. They may not need to be covered or covered less often than those that are exposed. Vegetables growing in these locations are not as likely to freeze during the winter.
Freeze damage to tomato plant
Freeze damage to tomato fruit
     Of course any of the warm season vegetables like tomatoes, peppers, eggplant, squash, etc. are going to freeze as soon as temperatures drop below freezing. In fact, they can suffer some damage when temperatures drop to the temperature of your refrigerator.
            Some warm season vegetables like beans may freeze to the ground at the hint of a freeze while others like peas, spinach and radishes may sail through the winter with no problems. Sorry that I can't give you a definite answer on that because there are so many variables.
Bush bean collar rot due to cold soils
            To be on the safe side get yourself a 1 ounce or more frost blanket and cover your growing area when temperatures are predicted to drop below freezing. Depending on the frost blanket, it can allow 50% or more of the light to reach the vegetables and it also breathes while it can raise the temperature under the blanket five or 6° F. It also keeps the wind off of the vegetables.
Crop cover (frost blanket) on raised bed for improved germination during cold weather
            Follow the direction and tack it down tightly so the wind doesn't get under it. Or put some weighted objects along the perimeter of the blanket. Don't use burlap or plastic sheeting. Spend the money, buy the 1 ounce or heavier frost blankets and they will last for three or four seasons or more.

De Witt makes a good one. So does Agfabric.

Sometimes Low Chill Apples and Hot Desert Clinate Don't Mix

Q. I heard the Israelis established a low desert apple tree. A few orchards have been established in the Phoenix area. I would like to learn more with the intent to purchase.
A. There are a couple of apples suitable for the low desert developed in Israel but the quality of the apple is typically not the best, in my opinion, unless you are a big fan of ‘Yellow (Golden) Delicious’. Both “Anna’ and “Ein Shemer’ apples were bred in Israel as a “low chill” apple for warm climates, not necessarily hot desert climates.

Anna grown in Las Vegas, Nevada in the Eastern Mojave Desert

            “Low chill” refers to the chilling requirement required by some fruit trees to flower and produce fruit the next growing season. A chilling requirement is a specific number of hours below a threshold temperature, usually around 45° F, so they “recognize” winter has passed.
            Just because a fruit tree has a low chilling requirement does not necessarily mean it produces good fruit in a hot desert climate. Hot desert climates are not the best places for apples. It doesn’t mean necessarily that an apple tree won’t grow but may have trouble producing fruit and decent yields and the flavor, texture and keeping qualities may be inferior. Apple fruit frequently sunburn in our hot summer climate and develop thick skins and high sugars but lower acidity. These climates are more suitable for stone fruit such as apricots and peaches.
Immature apple in the early stages of sunburn
Apple fruit with severe sunburn from lack of protection from late afternoon sun (West)
Hot deserts without cool nights close to harvest don’t develop a good balance of acids and sugars for flavor development. Cool nights are important for this. A 4000 foot elevation adds cooler nights which is very important for flavor development.
            The orchards in Arizona that I know of such as those near Wilcox, Arizona, are at a 4000 foot elevation or higher. Compare that with Phoenix at an elevation of around 1000 feet. These higher elevations and can handle some popular apples like Granny Smith, Fuji, Fuji, Gala and Pink Lady.
            Some lower chill apple varieties to try in hot desert climates include Dorsett Golden, Anna, Ein Shemer, Mutsu, Pink Lady and Sundowner. From my experience, try but proceed with caution with Fuji, Granny Smith, Gala, White Winter Pearmain, Winter Banana, Gordon, Yellow Bellflower and Pettingill. All of the apples do better with protection from late afternoon sun.

Sap From Plum May or May Not Be Borers

Q. I have a fruit bearing plum tree approximately 2 years old. I noticed an amber hard substance on the trunk. I think it’s borers. If it is, what can I do to save it and still be able to eat the fruit? 

A. The most effective way to kill borers is to apply a systemic pesticide and let the tree distribute this pesticide everywhere inside it. There is a very popular systemic insecticide available nearly 100% effective at killing borers if they are present.

            This insecticide is distributed everywhere (systemic) inside the tree and lasts for nearly 12 months. And yes, it is labeled for fruit trees that are bearing fruit as well as vegetables. This pesticide applied to food bearing crops makes me nervous for obvious reasons.
            Let me present to you an idea that does not require pesticides but a little work on your part. I have observed it to be about 80% effective. This requires a sharp knife and a method to sanitize it such as alcohol, butane lighter or even Pine-Sol.

Plum sap from a pruning cut in the spring
Sap oozing from the trunk of a fruit tree due to overwatering
            Plums are very sappy trees. Any injury to living parts of the tree cause sap to be produced. The production of sap is a defense mechanism against “intruders”. The tree does not differentiate between damage from boring insects and damage caused by pruning, invading diseases or environmental damage.
Extensive damage to the trunk of plum and bark is peeling from the west side
            To a plum tree, it’s all the same. It reacts by producing sap. If it is an intruding insect like a borer, sap engulfs and frequently suffocates it. If the damage by boring insects is extensive, loose bark easily lifts away from the damaged area because that area is dead. 

Borer damage under the bark leaving behind "debris" in the tunnels just under the bark from eating
            Damage from boring insects most first appears on the west or south facing sides of the trunk and limbs or on their upper surfaces. A tree may have damage for one or two seasons before you see parts of it suffering outwardly. On plums, sap is a good indicator something is going on.
            The only way to find out if a boring insect is involved is to inspect the wood under the sap for damage. It is easiest to do this after the leaves drop in December. You can wait. It’s cold now and they are not active.
            When you are ready, take a very sharp, sanitized knife and remove the sap along with the bark just under it. Look for damage to the trunk or limbs in the exposed wood. Boring insects leave debris from feeding, in tunnels, just under the bark.
Borer damage removal using a sharp knife removing all the damaged bark to fresh wood
            If you do not see damage to the wood under the sap, then this damage is not due to borers. Leave it alone if the limb appears otherwise healthy. If you see insect damage in the wood under the bark, cut and remove ALL bark from the damaged area with your sharp knife and let it heal on its own. If the damage is extensive and the limb is weak, remove it.
            There is no pesticide you can apply to the tree that will kill the borers AND leave the fruit safe to eat in my opinion even if it’s on the label and you can use it for that purpose.

Sunday, November 20, 2016

Making African Sumac Smaller the RIGHT Way

Q. Last November my next door neighbor’s African sumac trees were pruned to a trunk and branches. They were cut back so much I was sure they were being removed but was told they would leaf again. They did and are green and a lovely, smaller shape. I am planning to take the plunge with my tree but was advised to wait until February to avoid freezing damage. What should I do?

A. I will get to the February pruning. There is a right way and wrong way to radically prune large trees to a much smaller size. African sumac trees will survive this kind of pruning and you can get a much smaller tree. But the resulting growth from this tree will be weakly attached to the main trunk and large branches. This results in a lot of future wind damage to the tree and will cost more money to have this repaired later.
            Radical pruning that dramatically reduces the size of a tree must always be done during the winter months. Winter freezing damage to this tree does not happen very often here so I am not overly concerned about waiting until February. Not a bad idea though if the tree will look ugly until it regrows.
            We are talking about African sumac now. This type of pruning will not work on all large trees. If this type of pruning had been done to most ash trees, it would’ve killed them.
            The acceptable method for reducing the size of larger trees is a technique called “drop crotching”. This technique identifies the tallest limbs and removes them at a “crotch” in the tree, using a clean cut that leaves no stubs. When cutting trees in this way, the height is reduced but strong limbs remain to support the canopy and reduces future wind damage.
            Basically, “drop crotching” can be done to any large tree, not just African sumac. The type of pruning you saw done to your neighbor’s trees only works on trees that sucker easily from larger limbs.

            Dramatically reducing the size of trees by pruning is best left to tree care professionals, certified arborists, who have passed rigorous exams demonstrating that they understand and can practice highly specialized form of pruning correctly. They are more expensive but they know how to do it correctly.

Rock Dust and Venus Fly Trap

Q. Can you please tell me if it is possible or not to use volcanic rock dust on a Venus fly trap to promote its growth?

A. Rock dust is a marketing term which means a very finely ground powder from different sources that contains dozens of minerals in small quantities. It is thought that soils which are used for a very long time become depleted of some minerals that cannot be replaced with fertilizers. Recently, this term has become a hot topic among gardeners in the social media like YouTube and some gardening internet blogs.
            I became interested in it because I was getting questions regarding its use. I experimented with three different kinds of rock dust and compared them for one growing season in some raised vegetable beds. All of the raised beds were composted, as they would be, normally, at the start of a growing season.
            Perhaps it promotes growth in soils that do not have enough nutrients but I did not test that. I have not seen any advantages to vegetable growth when it is applied to raised beds and the soil has been composted and amended correctly.
            It does not hurt anything to apply it in small quantities and it can be inexpensive insurance if you want to be sure. You don’t need much.
            Venus flytrap in nature grows on very poor soils. It gets its nutrients primarily from the soil when it can get it. Alternatively, they also take nutrients from small insects that walk or fly into their trap. They evolved this way because of the poor soils. But catching insects and devouring them is an alternative to getting nutrients from the soil or leaves. 
            Regardless, the soil must drain well when growing these plants. Lava rock, perlite or pumice will help in that regard. They like high humidity so growing them in an enclosed terrarium will help. Adding rock dust to the soil will not hurt it. But help it? Perhaps if the soil is lacking in any of the plant nutrients found in the rock dust.
            Personally, I would use liquid fertilizer sprayed on the foliage much like you would orchids. This plant would like very much compost tea applied this way. They do not like rich, wet soils.