Xtremehorticulture

What Do I Do About Freeze Damage to My Plants?

From what I heard, Las Vegas had a couple of cold snaps. At The Orchard in North Las Vegas the low temperatures hit 16F at 4:30 am on February 15th while the high was 46F. Freezing weather can take several different twists depending on a few things.             First of all, if there is a warming trend during the cold winter months this can really mess things up for the plants. They think it’s spring, let down their winter guard and wham… it freezes and they are taken by surprise and they sustain more damage than they would if it had gotten colder more gradually.             If damage occurred to your plants and you can tolerate looking at them in that condition, then let them go until you see growth in a couple of months. The presence of vigorous new growth will tell you where to prune and whether the plant was killed, or just looks like it, but it isn’t. I will post more about winter freeze plant damage on my blog this week.  

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Figs Dying Back During Winter Months

 Fig with late spring freeze damage on the tips and leaves Q. I have a backyard orchard in Henderson with 14 fruit trees planted similar to what I have learned from the Dave Wilson videos and the UNR orchard. This is my 3rd year and I should be getting a decent amount of fruit. My problem is the figs. Two years in a row two fig trees have died to about 3-4 inches up the trunk. Last year I replaced both trees with new Kadota and Black Mission figs purchased from the nursery in pots. The new trees have apparently done the same thing. The trees are planted on the NE property line, so they get full afternoon sun. We had a very mild winter….I don’t really understand what is going on here. A. I am not sure what is going on either. If you are in a particularly cold part of the valley you could be getting some winter kill. It is not just the minimum temperature that matters. If low temperatures hit out of season (November or early December or mid February) they can’t handle the low temperatures they could normally handle in December and January. The important points in planting figs would be the same as the other fruit trees; add compost to the backfill at planting time, make sure it is planted the same depth as it was in the container, stake it the first year, it does not have to be whitewashed so don’t, keep the rabbits from it as they LIKE figs and will kill them, water them the same as other fruit trees, mulch them with wood mulch but keep the mulch away from the trunk 12 inches the first four seasons until established. Do not water directly next to the trunk but at least 12 inches away. Do not fertilize directly next to the trunk or you can kill them. They can be damaged by very cold winters, more so than apples or pears. I hope this helps.

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Rhubarb? In the Hot Desert?

Q. I would like to grow rhubarb here in Las Vegas. I live in Sun City Summerlin at about 3300ft. elevation. Any and all info would be appreciated such as variety, where to purchase, when to plant, shade or sun, in the ground or in pots, etc. A. We did try rhubarb at our orchard a couple of times with no success.  It could not handle the heat, primarily, which is my guess.  It is commonly believed that rhubarb will not grow in the Las Vegas valley and the purported reason among gardeners is that it needs some winter “chilling”. I am not convinced of this.             But my failure should not stop you because I did not give it a lot of my time and it was not planted in a protected area which it will require to “baby” it for the first couple of years until you learn how to manage it.             Rhubarb is probably not something I would recommend unless you are an experienced gardener and understand how to manipulate and manage your microclimates, soils and irrigation to get the response you need.              Your 3300 foot elevation will help a lot compared to our 2000 foot elevation at The Orchard. It would be very happy at 4500 feet or more. I would plant it in the ground.             Find a bright but cool location in your yard that will protect the plant from late afternoon sun.  Light shade will work just fine. I would usually suggest the north or east sides of a building. Winter cold is not a concern.             Pick a spot where it can be left undisturbed for the next 10 years.  This is a perennial crop, harvesting leaves and stems regularly through the growing season.             Dig the soil about 18 inches deep and amend with about 75% good compost. There is a lot of junk compost out there. In compost, you will usually get what you pay for.             Rhubarb can grow to four feet in height in the right climate. You will probably see it healthy during the spring and fall and really look quite bad during the hot summer months then rebound again in the fall. This is what we see with artichokes and other plants that are not supposed to grow here as well.             Plant the rhubarb rhizome with at least one good “eye” pointing up, three feet apart, about three inches deep. Fertilize with vegetable fertilizers. Mulch with straw to keep the soil cool and moist.             Place a basin around the plant to collect irrigation water and hand water until you see strong growth. Fertilize it in January to get started and lightly once a month when you are harvesting the leaves and petioles. The leaves are poisonous so just use the stalks or petioles.

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Navel Oranges? In the Cold Desert?

Q. We have a question about our 5- 6 year old naval orange tree. For the past 2 to 3 years we left the fruit on the tree until the weather man said freezing temperatures were coming. But with just cold nights, the fruit seems to dry out. Can we pick the fruit early and let the oranges ripen in the house? A. Just a note. Navel oranges are real tricky here in southern Nevada. They have to be planted in just the right microclimate or they will freeze. I forwarded this question to my counterpart in Phoenix, Terry Mikel, for a response.             Navel Oranges tend to be a bit persnickety especially when they are young, no matter the cold, heat or whatever.  If you are seeing lots of leaves and small branch damage, then frost will be an issue.             Freezing nights will dry out any citrus fruits. The juice inside freezes and crystals rupture cell walls and the juice simply drains out. The problem with citrus, if the fruits aren’t ripe on the tree, they won’t ripen any more off the tree. Sorry.               There is another possibility and I am hoping that the ‘damage’ is due more to being juvenile and not as much due to freezing damage. If the leaves aren’t hurt by the freeze, then the fruits wouldn’t be either. As the plant gets more mature, there will be more “metabolism” going on and thus better fruits.

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When Do I Pick This Pomegranate? I Don’t Know What I Have!

Some pomegranates have wonderful color inside like this ‘Wonderful’ pomegranate Q. I planted about 30 pomegranate bushes two years ago. I bought them from a nursery and they told me that I was getting a variety of exotic species. But they had them in the nursery so long the tags were all gone. They are all thriving now and most have a fair amount of fruit this year.  How do I determine when the fruit is ripe? Do they get easy to pick, like they nearly fall off the stem or is that even a factor? Do the seeds need to turn red? They are getting kind of leathery on the outside but most of those have seeds that really aren’t red at all. They are still a little tart but that may be expected. A few are smaller and really red outside and really quite red inside, but those are really bitter. So the real question I am asking is – how do I figure out when they are ripe? A. If we were all growing the same pomegranates it would be a lot easier. But not all pomegranates mature at the same time and they not all look the same when they do. Pomegranates can come in a wide range of colors             Some pomegranates are yellow on the outside, some red, some striped, some dark purple. Also the seeds on the inside are not always red or dark red. Some of the prettier ones are but no a variety like Utah Sweet (which I think you may).             They are a great variety but they do not look nor are they as pretty to look at as the Wonderful variety which is the most widely planted variety in the US. Some, like Utah Sweet, have seeds that are soft and nearly edible and in some cases people do eat them. Others, like Wonderful, have seeds which are hard. Some pomegranates may tend to split when they are ripe             Some have low tannin content and so are not bitter at all while some are quite bitter. Bitterness is an acquired taste and in some cultures is preferred. Think of the bitterness in beer or bitter melon. Some have a delicate balance between bitterness and sweetness that many people relate to the true taste of a pomegranate.             Some ripen by September while some ripen near Halloween.             Frequently the fruit will separate from the tree with a gentle tug and twist when ripe. It is true though that if you know which variety you have you can usually judge by its color and time of year.             Another way is the calyx end or the bottom where the “king’s crown” is. When it flares outward it is a good sign it is close to being ready.             Splitting of the fruit can be another indicator. If birds start to attack the fruit when they split that can be another indicator. Ground squirrels may also attack the fruit.             In any case they are ready when you think they taste good. Start looking at them around mid-September and pick a nice looking one and sample it. If it tastes good, then look for some at the same stage of maturity and harvest. Harvesting ripe off the tree can last a month because they are at different stages of development.             If not yet ripe, wait a couple of weeks and try another one. Keep going until you are satisfied you have the right timing. Mark it in your calendar. Take pictures of the mature fruit, send it to me and let me see if I can help you identify it.

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Keys to Healthy Landscape Plants in the Desert

Q. We have several shrubs with an eastern exposure that appear to be very distressed or dying. The first three photos show the entire shrubs. Photos 4 and 5 are close ups of the distressed area. Photo 6 is a very healthy plant in the same area but with a southern exposure. Irrigation is excellent; enough that water is standing in the bed upon completion of the water cycle which is five minutes and four times a week in the hot summer.  Japanese euonymus in question A. Thank you for the pictures.  There are several things that might be going on at the same time with these shrubs.  They appear to be variegated mock orange and Japanese euonymus.  Many of the leaves are yellowing and scorching or turning brown and dying from the tips back.              Most people will look at these pictures and say they are not getting enough water.  Another person might look at the same pictures and say they need iron. Another person may look at the same thing and say they are getting too much water. And even another person may look at that and say it is salt damage. The problem is they could all be correct just based on the pictures.  Leaf damage closeup of Japanese euonymus             Many of these things, and even more, are interrelated.  Just giving more or less water or even iron may not solve the problem alone.  Let me just give you a rundown of the problems that I see as possibilities: plants planted in the wrong spot in the yard, improper pruning, lack of additions to the soil to improve it, wrong type of fertilizer and improper watering.              From these pictures, any of these could be a possibility and there could be combinations of things going on.  Let me handle each, one at a time and perhaps you can make the best decision. First of all plant location.  If this is a very hot location, facing south or west with lots of reflected heat and light, then they will not do well in this spot. This does not mean that they cannot survive there; it just means it will require more effort to keep them looking good if they are placed in spots that are extreme for their best health.  Variegated mock orange with scorching and dieback             By finding the best location for plant in a yard means that they will require less time, energy and money to keep them looking good.  A very hot location will be even more difficult if there is no air movement and they just sit there and bake. Pruning. These shrubs appear to be pruned with a hedge shears into the shape of a gumball.  This type of pruning may work for a few years but eventually this type of pruning makes the plants look ugly and contribute to their poor health.              Pruning with a hedge shears should be reserved for hedges, not shrubs.  This type of pruning forces older wood out closer and closer to the perimeter of the shrub.  Young or juvenile wood is the only wood that is removed.  Closeup of variegated mock orange leaf scorch             My guess is that you have a landscape maintenance company doing the maintenance.  This is how they prune. They don’t know any better. Very few, if any, prune shrubs properly. The proper way is to remove ¼ to 1/3 of the shrub each time it is pruned, forcing new growth to come from old wood deeper inside the canopy of the shrub.  This rejuvenates the shrub, adds more juvenile wood to the canopy and keeps it young and vigorous. Soil amendments.  I could not tell from the picture but these shrubs will perform better if they were growing in organic mulch or wood mulch.  Not bark mulch.  The chipped wood decomposes into the nutrient poor soil and adds vital nutrients for the shrubs.              Rock mulch also breaks down but adds only minerals to the soil.  The shrubs will perform better if compost is added to the base of the plants and watered in with a hose.  Compost should be added to the list of fertilizers and soil improvements for these plants each year.              The first year I would add about 4 cubic feet of compost per plant along with its fertilizer applications.  After two or three years of this I would probably only add about 2 cubic feet per year.  Then of course the wood mulch is an added on top of the compost.  You should start to see improvements after one full season of growth after the additions.  Fertilizers. The same type of fertilizer used for lawns will do a good job on most shrubs as well.  This is usually a fertilizer with a ratio on the bag of 3-1-2 or 4-1-2.  An example of a 3-1-2 fertilizer would be something like 12-4-8 and a 4-1-2 might be 16-4-8.  You will not find these numbers on fertilizer bags exactly but at least you can get the idea of how the numbers should go up and down in sequence.              The next fertilizer you need is an iron chelate such as iron EDDHA.  It is expensive but can go a long way since of the small amount is needed each year.  My apologies to other nurseries and outlets but I know that Plant World Nursery carries this iron chelate.  If others do, let me know please. Fertilizers are added to shrubs in February of each year. Watering. The frequency of watering will vary during the year but during the heat they will probably need water about three times each week.  As it gets cooler, decrease that to twice a week, cooler yet, than once a week, etc. In the winter it should be no more frequently than once a week.             The gallons of water to apply is going to be difficult for you to judge because you operate an irrigation clock in minutes. Somehow

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Buying New House May Need Lots of Plant Care

 Trees in the readers landscape Q. My wife and I just bought a house. The house has a backyard with a good selection of different fruit trees and non-fruit trees. We have noticed that as the trees were bearing fruit, the fruit looked a little spotted and not exactly healthy. The same thing was happening to the leaves, spotted & brown around edges. I thought it was due to lack of water? Then we started to notice that all most all the tree stumps had their bark opening in big patches and sort of peeling away. And now we see liquid, all most sap like coming from these areas. The Peach trees bark actually looks white on the outside! The trees don’t look healthy at all. It seems the trees were planted in 2004. A. After looking at all the trees sent to me in pictures, my first thought was that they could use 4 to 6 inches of wood mulch covering the soil beneath them.  You would see a big difference in their growth and health the season following an application.  Apple tree and trunk damage             You can pick up free wood mulch from the university orchard in North Las Vegas.  You just have to drive out there and get it. You can get directions by calling the master gardener helpline any Monday through Friday at 257-5555. The orchard is open for doing this on Tuesday and Saturday mornings.             All of the trees seem to have a lot of trunk damage probably due to borers.  I would to take a sterilized sharp knife and remove all of the loose bark and damaged parts of the trunk down to undamaged wood. At this point you will make your determination whether to keep them or start over. If the damage is over half way around the trunk, you might consider eventually replacing them. Less than that, it is probably worth trying to save them. Plum tree with trunk damage             If you decide a tree is worth keeping then trim the borer damaged areas, removing dead bark, all the way down to fresh, healthy tissue. It is okay to cut into this healthy tissue with a clean knife. It will heal over just fine as long as the trees get adequate fertilizer and water.             Next, paint the trunk and exposed limbs with diluted white latex paint to help prevent sunburn and lessen borer future borer damage. Dilute the white latex paint half and half with water.              Make sure the trees are getting adequate amounts of water on a regular basis. Right now, in late January, that should be once every ten days or thereabouts with about 15 to 20 gallons at each application. Got to once a week in February and twice a week in May. Peach tree with trunk damage             Fertilize each tree with a fertilizer that has all three numbers and no zeros. An example might be 10-20-10. You will probably not find this fertilizer exactly but the important part is that the middle number is highest. The easiest thing to do is to buy fertilizer stakes and pound them into the ground where the soil is wet after irrigating and at least 12 inches away from the trunk.             At the same time apply an iron fertilizer to the soil, specifically iron EDDHA chelate. All in all they look remarkably healthy except for the insect damage. Make sure you get wood mulch and apply fertilizers to the trees again next January.

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Bigger Black Mission Figs With More Water

Black Mission figs at The Orchard  This is what I have been telling you guys. This is taken from the publication, California Agriculture, published back in 1999 by David Goldhamer and Mario Salinas from the University of California Cooperative Extension and the Ag Research Center in Parlier. The research was focused on the San Jaoquin Valley in California. An analysis of tree-water relations and fruit yield indicates that Black Mission fig production responds favorably to a higher volume of water applied during the summer than is currently used by most of the industry. Larger fruit size was the primary yield component responsible for the improved production and profit. Based on historical reference crop evapotranspiration rates and the crop coefficients determined using data from this study, summer applied water should be about 36 inches for maximum Black Mission fruit production and grower profit in the Madera area. Bottom line. If you are unhappy with the size of your figs or fig production, make sure your fig trees are not water stressed when they are producing figs.  Use surface mulches to conserve water, keep the soil from wild fluctuations in water content that will affect fruiting and the mulch helps keep fallen fruit from rotting on the ground. Open publication – Free publishing – More fig production

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