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Tuesday, October 22, 2013

Membership Climbing Fast in Desert Horticulture Discussion Group

This is a discussion group for all of you who want to exchange ideas about desert horticulture... a very different breed of gardening. You have to know what you are doing to be a good desert gardener and it will test your limits!

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Rabbits Do Not Jump Over Fences

Q. We are planning a wall to surround our yard so we can keep the rabbits out. We live in Sun City Anthem in Henderson. We have been told that the local rabbits can jump very high, and our three foot wall will not work to keep them out. Can you let me know? I want to build it at least that high, and maybe a little higher.

A. I don’t agree with the advice you were given. Our chicken coop wire (with 1 inch holes) at three feet tall was very effective at keeping them out of our vegetable plots as long as they could not lift the bottom edge of it with their noses or dig a little bit and get under it.

            However, baby cotton tails can squeeze through a 1 inch hole at a dead run.

            Usually animals will not jump walls if they cannot see the other side. If they can jump to the top of it and look, then that is different. I have never seed rabbits do that.

            But check and make sure there are no gaps in the wall itself. If they can get their head through a hole, they can get the rest of their body through it as well. We had to bury our chicken wire only about two inches deep to keep them from getting under it.

Fixing holes in rabbit fence around vegetable plots at the UNCE Orchard

Recommended Varieties of Almond, Pluot, Nectarine, Pear for Hot Desert Climates

Q. We have had several trees die over the past year so we are looking for replacements that will do well here.  We do have a Kiefer pear which produces really small, rock hard pears that never seem to ripen. Some suggestions please for almond, nectarine, pluot and apricot.

A. If I were to plant only one almond tree, it would be Garden Prince. It is smaller than the other almond varieties and the flower is a beautiful purplish white instead of plain white. For a home landscape that needs a smaller-sized tree, beautiful flowers and wonderful nuts, Garden Prince can't be beat. It is self-pollinating so doesn't need a second almond for pollination.
Almonds in bloom at UNCE orchard

            Arctic Star nectarine has a remarkable flavor in our climate. It is floral, buttery and one of the best fruits I have ever tasted. It makes wonderful sorbet. But you must remember that you will have problems with thrips with that will result in horrible scarring of the fruit if you don't keep it under control. It must be sprayed.
Nectarines at the UNCE Orchard.

            Remember that pluots require a pollinator tree for improved fruit set. A good pollinator for pluot is also a great plum for our area called Santa Rosa. If you already have a Santa Rosa plum or your neighbor does, you don't need a pollinator tree for pluot.

            Among the pluots, the best tasting in my opinion is Flavor Supreme. Second on my list would be Flavor King. The problem we have had with Flavor Supreme is low fruit production even with a pollinator. Flavor King has such a large fruit set, it must be thinned.
Flavor Supreme Pluot at the UNCE orchard

            The second problem with all pluots is our late spring freezes in the developmental fringes of our valley which are typically colder.

            When we get a freeze and they are in flower, you probably will not get any fruit that year. So expect fruit in two or three years out of every five if you live in these colder fringe areas of the Valley.

            A great apricot, that is not really an apricot but a cross between an apricot and plum, is the aprium. The fruit looks identical to and is marketed commercially as an apricot. It has flavor attributes of plum and apricot in the fruit. The best aprium out there is called Flavor Delight which will be available from the UNCE Orchard.
Flavor delight aprium 15 yrs old kept at 7 feet height at the UNCE Orchard

            Your Kiefer pear is very different from pears like Bartlett or d’Anjou which are desert pears. Desert pears will get soft and buttery in texture if you harvest them slightly early and let them ripen at room temperature off the tree. Kiefer pear is a salad pear that is also great for canning and used in stuffing for fowl like turkey or chicken.
Keiffer pear ready for harvest. Note the color change.
            Kiefer pear should be harvested just like you would a desert pear. To judge when to harvest I use a change in color of the fruit and smell. The fruit color will change from green to yellowish green and you will detect a distinct pear aroma from the fruit. They will still be hard when harvested.
Bartlett pear ready to be eaten and should not be harvested at this stage but earlier when there is still a hint of green

            You can also sacrifice a fruit and to cut it open and check the color of the seeds. They should be dark brown when the fruit is ready to harvest. But if you compare Kiefer pear with a desert pear, you will be very disappointed. They are both great, but in different ways.

Dont Prune Big Branches in the Heat

Q. My plum tree is 10 years old and I dumbly cut some secondary branches two or three months ago. The tree was infected or inhabited by some bug that had dozens of points with sap dripping for a few years now. It’s lost most of its leaves already. Should I cut and run?

A. You can usually cut small branches from the tree at any time. But if you cut larger branches from the canopy and it opens the tree and the interior limbs to direct sunlight during the summer months you could be in big trouble.
Plums are very sappy trees. they produce alot of sap when injured. Here a limb was cut when the tree was actively growing and it exudes sap as a reaction to being wounded. the sap helps cover the wound and protects it. if bugs like borers are in the damaged area there is a good chance they will be suffocated.

            Never remove major branches from a tree just prior to, or during, the summer months. Larger branches should only be removed in the winter.

            Your plum is not tender to winter cold but if a tree is tender to the low temperatures of our valley there might be freezing damage during the winter. In cases like these you delay pruning until you just start to see new growth coming out in the spring.
Here Pittosporum was cut back and sunburn resulted and dieback of the plant to shaded areas.

            Cutting some branches will not cause the leaves to fall off of the tree unless there were some major problems going on. Make sure that the leaf drop did not just happen for other reasons such as the water was accidentally turned off or the source of water was plugged.

            I would water deeply now with a hose and again in about one week and see what happens over the course of the winter. If the branches are dead, they will snap like a twig. If they are still alive, they will be supple and bend without snapping. If they are supple, then wait and see what happens this next spring.

Peach Miniature Selection for Containers

Q. I'm super excited to order some fruit trees this year from the UNCE Orchard but it only makes sense for us to have them in large containers. Which varieties would do well in containers?

A. It really would be better for you if you get miniatures for your containers. Unless you are a super Duper gardener I wouldn't recommend standard size trees in containers. They are just a lot of work compared to miniatures.

Genetic dwarf or miniature apple from Dave Wilson Nursery, "Apple Babe"
            We are not ordering miniatures for the public at the UNCE Orchard. Typically, the fruit from miniatures is not as high quality as we can get from standard sized trees. That being said, if I were putting a fruit tree in a container I would be selecting something that stayed as small as possible. We will see if we can come up with some miniatures for next year.

Miniature Peaches with Descriptions from Dave Wilson Nursery

Miniature or genetic dwarf peach from Dave Wilson Nursery

Amargosa Valley Fruit Tree Selection for Bees

Q. Do you have any suggestions on fruit trees for the Amargosa Valley area? I have an apiary out there so I try to plant things that are good for the bees but that will survive the heat and cold out there.

Amargosa vineyard in its first year in 2006

A. Nearly all of the fruit trees that do well in the Las Vegas Valley will do well in Amargosa Valley. You have a commercial winery there that sells its grapes to Pahrump Winery and this same orchard began producing olive oil this past year.

            The problem with fruit trees is that they have a narrow window for flowering and so the bees only get to work them for a short period. Fruit trees that have a longer flowering period would be pomegranate or spread your flowering time out with different types of fruit trees.

Bee in a peach blossom at the UNCE Orchard
            Early bloomers are the stone fruit like peaches, apricots and plums and later the pome fruits like apples and pears begin flowering.

            Vegetable crops and flowers would give your bees a lot to work for a longer period. You should have a lot of leafcutter bees out there from the alfalfa.
Leafcutter bee damage to apricot leaf at the UNCE Orchard
            Make hauling water to their hives as easy for them as possible during the hot summer. Make sure the source of water available to them is clean and you should have no shortage of bees. This could be irrigated basins at the fruit trees that are operating when bees are flying.

Low Chill Cherries and Other Fruit for the Desert

Q. I heard about a cherry tree from the Dave Wilson Nursery website that has very low chill hours. Can we order these from the UNCE Orchard?

Low Chill Fruit Trees for the hot desert

A. There are low-chill sweet cherries but they have been in such high demand we have not been able to secure any in past years.

            However, we have had no problems growing high chill hour apples, peaches, apricots and plums here in the valley. They have been productive for over 15 years. So the idea of chilling hours being an “on or off switch” for producing fruit should not always be a consideration for homeowners when selecting fruit varieties.

            Sweet cherries are a problem in southern Nevada unless you can plant them in a backyard where they have protection from wind and there is some humidity from a pool or a lawn. We had many different varieties of sweet cherries and produced only about 12 cherries from all of them in 15 years at the UNCE orchard.

We could not get sweet cherries to produce at the UNCE Orchard even with good flower production and lots of pollination opprotunities from many different sweet cherries planted in the same area

            Sweet cherries flower extremely well so chilling has not been the problem. The problem has been in setting the fruit and keeping it on the tree. Poor flowering is what you would more likely expect if you didn't have enough chill hours.

            Other people in town have had success with sweet cherries but nearly all of them appear to be in backyards that are protected and have a higher humidity. The people in Las Vegas who have been growing sweet cherries successfully tell me that they have grown Bing, Lambert and other common varieties.

            You might have more luck with sour cherries and they are more versatile anyway. We have no reports to give you yet whether they will work here or not because they are still being tested.

Buffalograss an Alternative Grass for Southern Nevada

Q. Is Buffalograss an acceptable turfgrass for our climate?  I am aware its appearance is nothing like tall fescue or hybrid bermudagrass. We are looking for a grass-like look without the high-water use and also the medium to high maintenance that conventional turfgrass demand.

One of the improved Buffalograss varieties which compete with hybrid bermudagrass for looks in southern Nevada.

A. Actually the newer varieties of Buffalograss look as good as anything else. Buffalograss is similar in its growth to hybrid Bermuda since both are warm season grasses. In other words, both Buffalograss and hybrid bermudagrass will turn brown in the wintertime.
            Bermudagrass can be overseeded in the fall to maintain a green lawn during the winter. Buffalograss should not be overseeded.
            The newer Buffalograsses have come a long way but the problem is getting the good varieties locally. You would have to order out of state off of the Internet. I would use plugs rather than seed.
            Research done by Arizona State University has demonstrated that Buffalograss uses about the same amount of water as hybrid bermudagrass which is 25 to 40% less than tall fescue. So there would be no water savings over hybrid Bermuda if you were to plant Buffalograss.
            Buffalograss grows more slowly and requires less fertilizer than either tall fescue or hybrid bermudagrass. In fact, Buffalograss does not like nitrogen fertilizer and does more poorly if you fertilize it.
            The advantages of Buffalograss is that you don't have to mow it as often and it does not require, nor should it ever have, high levels of nitrogen fertilizer applied to it.
            You can purchase Buffalograss as plugs but make sure you get one of the newer varieties if you want a well-manicured look to your lawn.

Reputable online source for Buffalograss plugs
I would select University of California's Verde variety for the desert southwest or desert conditions in general.

The following is from a University of Nebraska publication by Terry Riordon

Vegetative Plugs and Sodding – Stand establishment with sod of improved turf-type buffalograss will decrease time required to cover the planted area. Plugs are helpful when early landscape aesthetics or soil stabilization are important.

Vegetative Plug Establishment – Plugs should be 2 inches or more in diameter with a minimum depth of 2.5 inches. Spacing between plugs can be varied, depending upon how quickly full coverage is desired. Vegetative plugs should not be placed further than 24 inches on center. If site conditions and preparation are less than optimal, reduce placement interval to provide a full stand within the first growing season.

During establishment, it is important to keep weeds to a minimum. Periodic mowing at a 2 to 3 inch height will help minimize weed competition.

Plug condition is important to establishing a successful stand. Plugs harvested from an established field, placed in trays, fertilized and watered in a greenhouse or under clear plastic for 4-8 weeks are called pre-rooted plugs. For early spring and summer plantings, pre-rooted plugs have been shown to establish more quickly than those not pre-rooted. Plugs harvested in March, pre-rooted and planted in May will, under proper growing conditions, establish an acceptable stand by fall.

Plugs not pre-rooted need 3-4 weeks to initiate growth and may not provide complete cover by fall. Newly harvested plugs may "go brown" after planting due to transplant shock. Proper establishment methods can help minimize this off-color period and insure good rooting of the plug. Applying a starter fertilizer at 1 lb of phosphorus and 1 lb of nitrogen per 1,000 sq ft will aid in establishment and growth. Irrigation will not only help maintain active growth but also will decrease the length of time required for establishment.

Pomegranates Come in a Wide Range of Colors

Q. I planted a pomegranate tree two years ago and this year it produced six fruit. One was of decent size while the others are on the small side. When the large one split I picked it only to find the inside was light pink. The seeds were well developed but not the expected red color.
What can I do to improve the fruit on this tree? 
This is what we expect to see inside a pomegranate because we are used to seeing only Wonderful variety of pomegranate

A. The key question will be how sweet the fruit was. Some pomegranate varieties will have fruit where the insides, the arils, never develop a dark red color. Some of them can be quite pale and anemic-looking in color. 
This is Ambrosia pomegrante. The arils are pale, nearly white. This fruit is ripe and ready for picking. However, I was not very impressed with the taste of this variety when freshly picked. It improved alot if kept in cold storage for a couple of weeks. Harvested in September in southern Nevada. Still a variety I would not recommend for our climate.

            You would not expect this on a pomegranate variety such as Wonderful, which has dark red outer skin while the fruit inside, the arils, are also dark red. Because this type of pomegranate represents probably over 95% of all our pomegranates planted, everyone thinks a pomegranate has to be dark red on the outside and dark red on the inside.
            This is not true. There are several varieties of pomegranate which do not. Pomegranate rind or skin can vary in color from lemon yellow through all shades of pink and red all the way to purple. The insides can be nearly white to dark red or even purplish red. The key to whether they are ripe is the taste.
This basket of pomegrantes will give you an idea of the wide range of colors that pomegrantes can come in. (Picture from Acta Horticulturae, publication of ISHS).

            If you have one of these varieties which are not red, you will never get dark red on the inside or the outside no matter what you do. A good example is a fairly common variety that we call locally Utah Sweet. You will find quite a few of these growing in the Las Vegas Valley.
            When a pomegranate is ready for harvesting the insides will become sweet tasting. The amount of "pucker" or tanins or bitterness will vary as well from extremely “pucker” to very sweet with very little “puckery” flavor depending on the variety. But the key to when it is ready is how sweet it is, not necessarily colors.
Here is a pomegranate I found for sale in a village in northeast Tajikistan. Very unique. Yellow on the outside with very beautiful dark red arils on the inside and very tasty.
            If your variety of pomegranate is the darker red type, just wait longer and leave it on the tree. If it is a variety that will never turn dark red, then look for the fruit splitting and begin to start sampling for sweetness.
            Depending on the variety, pomegranates begin to ripen in September and can last well into November. Wonderful pomegranate, the most common variety in the Valley, is usually ready right around Halloween.

Plant Garlic Cloves and Onion Seed in October and Early November in Southern Nevada

This is the ideal time to plant garlic from cloves and onions from seed. I have grown perhaps 25 or 30 different varieties of garlic and about as many sweet onions. I have not found a garlic or onion yet that has not done well in our climate. Both long day and short day onions do well here, from Washington’s Walla Walla to Georgia’s Vidalia sweet onion. Garlic as well from softneck types to hard neck.

Walla Walla onion grown at the UNCE orchard in North Las Vegas
            It is too late to order garlic for planting or onion seed. You can still find onion seed in some stores. Most of the garlic is imported and not all that interesting but you can find some specialty garlic at the farmers markets or specialty stores like Whole Foods you can use for planting. 
Garlic planted with drip tape and mulched with straw now harvesting scapes (flower stalks with unopened flowers)

            Break down the garlic bulb into its cloves. This will leave tiny wounds on the fat end where they were attached. Select only the largest cloves for planting and the rest for cooking. Inspect the cloves very closely and if any have tiny brown spots on the skin of the clove then use them for cooking as well and do not plant them. 

            Leave the separated cloves out overnight and let the wounds heal. The day you plant garlic cloves, soak them in tepid water for a couple of hours first. This will speed up their emergence from the soil. 

            Plant these cloves in prepared garden soil about two inches deep and four inches apart with the fat end down. At this time of year, I would water these cloves daily if the soil drains easily. If your soil does not drain easily, then irrigate every 2 to 3 days. Once they have emerged you can water less often.

Volunteers separating the cloves out from the bulbs for planting. These were purchased as certified disease free planting stock but you can use store bought garlic in a pinch.
            Broadcast onion seed on top of good garden soil. The seed doesn't need to be spaced far apart since you are just going to grow them into transplants and move them next March. When you move these transplants they will be planted about 4 inches apart into rows or blocks. That is when proper spacing is critical.