Xtremehorticulture

Xtremehorticulture of the Desert

Sagging Yucca Arms Need Support or….

Leave a Comment / yucca sagging arms /

Q. I have this Yucca for about 15 years and I am getting concerned about all the growth on the arm that you can see from enclosed photo. It is getting real heavy and I don’t want it to snap. Any suggestions? Readers yucca with sagging arm. A. Your photograph was forwarded to me to look at . . . . It is pretty cool that the arm with seeming all the foliage is really an arm that sprouted at least 3 terminal buds  . . There are three, maybe more but I am sure I can count 3 developing arms from the end of the one arm making the arm look exceedingly well foliaged . . .That’s just the nature of many of the Yuccas . .  Just look at the more vertical arm and you can see a number years ago that arm set an off shoot For a possible engineering solution . . .If your neighborhood association’s codices, deed restrictions or anything else that HOAs might impose allows it I would suggest propping the arm some where along the arm that is parallel to the ground . . I have seen a single 2″ X 4″ stuck up straight up might suffice but two 2″ X 4″ to form an no-symmetrical “X” with the upper crossing would be higher than the bottom half and use the crotch to prop the arm up . . . It can be made a bit more ‘rustic’ by using older more weathered lumber . . .If you want to fashion a cradle in the crotch of the “X” there will a wider spread of the weight out more than the direct contact with the two 2″ X 4″ . . By supporting it the side shoots forming the crown will begin to grow and the weight plus the moment arm affect will cause it to be heavier and heavier with age . . . Cutting it off is obviously an option also . . Terry Mikel

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Overgrown Red Yucca Can Be Divided for Smaller Space

Leave a Comment / Hesperaloe parviflora, Red Hesperaloe /

Q. I’m replacing some red yuccas that have grown too large for a three foot area, unprotected in full sun. They spill over into the walkway where my grandchildren have been getting stabbed by the leaves. Can tree roses handle that kind of weather? Red yucca overgrown near a sidewalk. It is possible to gently dig them up in the fall or early spring, divide them and replant smaller plants or ‘starts’ that will again fit in this space. A. Red yucca probably not the best choice for a fairly narrow space. Red yucca will get larger in diameter each year and needs to be divided every three to four years to keep them smaller and full of blooms. Red yucca younger and occupying a smaller space.             If you were to dig red yucca out, divide them and replant a start from your divisions you could have kept them in that sized area. Normally you would have divided them in the early spring, around early February, or mid-fall months around the first of October.             Tree roses require special pruning techniques and may not be the easiest rose to plant there. Regular hybrid teas or floribundas would be a better choice there. If you do go with roses just make sure that the soil is covered with wood mulch. By the way, red yucca is not a yucca at all. It just looks kind of like one.

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Blackened Dead Leaves May Be A Really Bad Disease Problem from Last Year

2 Comments / asian pear, black pear leaves, dead leaves on apple, erwinia, fireblight, pear /

Q. I planted a five-gallon pear tree about three springs ago and it seems pretty happy espaliered along my west-facing block wall, but a few new leaves on three of the branches have some kind of black rot on them. It has rotted away part of the leaf on some of them. Can you tell me what this disease is and whether and how to fight it? Also, don’t know if this is for the same reason or not, but the pear did not have blossoms this spring. If it matters, it’s a Comice pear. I have a Bartlett planted nearby at the same time, and it seems unaffected. A.  Two things come to mind. First, last year was a pretty bad year for a disease that attacks European pears, Asian pears and apples. This is a bacterial disease called fireblight. What you are seeing now in spring 2014 may be a remnant of fireblight from the previous growing season (2013). It can be particularly bad on Asian pears. Again in about May you see some of the new growth dying back from fireblight, dead leaves and upon close inspection the blackened growth. New succulent growth in May in our climate causes the blackening of the growth and the telltale hook or shepards hook commonly talked about with fireblight This disease can be devastating to these fruit trees. The disease normally starts near where the flowers are produced. This disease can spread down the limbs and in the case of Asian pears in our desert climate, the disease can kill the tree. It normally does not do this to European pear or apple here in our climate. The disease turns these parts of the plant and even some small limbs dark black, like they were scorched with fire, hence the name. A telltale sign is distorted young growth in that area that is bent backwards into a hook. If this is the case or you suspect it might be then cut out this diseased portion 12 inches below the infection. Sterilize the pruning shears or saw with a strong disinfectant such as alcohol or Lysol. Do that between each cut on that particular tree to prevent reinfecting it. I pay particular attention to the weather during bloom time (that is happening now in apples and pears in our climate). If it is rainy and windy I can usually expect problems from fireblight. That is exactly what happened this time last year. The second thing is that pear leaves normally turn black if they are injured in some way. That would be a normal color for damaged or dying or dead pear leaves. So if it is just affecting the leaves and they are black then I would not assume it to be fireblight. But if it is in the branches then you need to cut out the infection as I described.

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What You Need for Your Vegetables Now

Leave a Comment / todo, what to do to vegetables in March april /

It’s the end of the season for cool season, winter vegetables now after mid-March. Warm season vegetables should be going in the ground now if they haven’t already. In protected hot microclimates it should have been sooner. Here is what you need to do now in our hot, desert climate. Warm season vegetables include tomatoes, peppers, eggplant and your squashes, cucumbers and melons. When you buy your vegetable transplants, get small ones. A good size is about six to eight inches tall and bushy. While you are at it, buy some compost, a starter fertilizer, some Dipel or Thuricide and insecticidal soap. Mix the compost with your garden soil when planting the transplants. After planting, sprinkle the starter fertilizer around the base of the plant and water it in. Don’t fertilize again until you see fruit setting. Lightly fertilize all vegetables once a month.   Spray plants with soap sprays twice a week. The soap sprays are more effective if you spray under the leaves, not just on top. With squash you might have to cut or pinch off the lower leaves so you can spray under the other plant leaves. Spray soaps early in the morning or late in the day as the sun is setting and bees have gone home. Alternate soap sprays with Neem if you like Neem oil or other botanical oils. When seedlings are starting to pop out of the ground, protect them with a Dipel or Thuricide spray or dust applied to the soil immediately around them. This helps protect against cutworms from damaging your new plants. After watering the plants you have to apply it again. Amend the soil at the time of planting, spray regularly for pests, fertilize lightly once a month and you will have a better harvest.

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Cat Claw Vine Beautiful in the Desert But Not Elsewhere!

3 Comments / fertilize, invasive cat claw vine, mulching, water /

Q. I planted six cat claw vines two summers ago in full sun. They are on a drip system and I hope to wean them from regular water once the area is covered. I believe you mentioned to avoid mulching cat claw vine.  Of course I had already done this and the plants are struggling. A. Cat claw vine is a very vigorous tropical and semi tropical vine that is one of those rare plants that does well in the tropics and the desert. If the mulch is staying wet and in contact with the plant then this might be a problem.  Claw Claw in Arizona             Cat claw vine is considered a pest in much of the southeastern US, from Florida to central Texas. I would not plant this vine in wet climates.             It does like to grow along waterways and it would probably be invasive if it escaped along the Colorado River or any of our surface waterways in our lower elevations of southern Nevada.             Not so in the desert where we can restrict its growth with drip irrigation.It is a beautiful vine, it is aggressive and nearly pest free. It may die to the ground during cold winters or just drop its leaves when it gets below freezing.             This vine may have some trouble getting established on south-facing walls during summer months. But once they cover the wall they will do a good job shading it and reducing the reflected heat and glare from that wall.             It will do well in rock mulch provided it gets adequate water and the soil was composted at the time of planting. I would not allow it to climb on stucco or house siding as it may cause some minor damage.             When it does climb on these surfaces, pull it off, cut it back and let it regrow a different direction. This vine should be fine growing along the ground or allowed to climb cinder block walls.             In your particular case I would pull mulch away from the trunk at least a foot until the plant gets firmly established. Fertilize once a year in the early spring to push new growth.             It loves the heat so fertilizing lightly during summer months will not hurt it. As it gets older it tends to get woody at the base revealing wood stems. To reinvigorate it cut off one of the older stems and let it regrow with new leaves to cover bare areas.             You can cut it back to the ground in late winter after it has been established a few years. The underground tubers will send up new shoots that will start the vine all over again.

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Spanish Dagger Yucca Ready to Fall Over!

Leave a Comment / why is my yucca leaning falling over, yucca falling over /

Q. Our Spanish dagger yucca was doing great but it’s leaning badly now. Is this normal? A. I think this plant has been getting watered too frequently, the soil is staying wet and not draining.              Normally the trunk has some pretty good taper when water is much less often and so it will stand upright when it goes through these periodic wet and extended dry cycles. When it grows slowly due to infrequent watering the trunk does not get spindly and fall over.             In wetter climates this has been a problem with this plant when it gets about 5 feet tall. When water is present all the time it will take advantage of the excess water and grow as much as it can in length and not in girth. It gets top heavy and topples over.             It wants to reproduce and it does not care if it is upright or laying on the ground to do that. In fact, it is possible it could root from the trunk into the soil as it is lying there. This plant can root from trunk cuttings when propagating it.             If you don’t like it lying on the ground then cut it off close to soil level and leave those “pups”  at the base to grow into a clump or you can divide them in the fall, or even now, if you are quick about it.

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Majestic Beauty Leaves Browning on the Edges May Be Drip Problem

Leave a Comment / 24 inch box tree, how much to water, leaf dying, leaves browing, newly planted tree, scorching /

Q. The edges of the leaves on my Majestic Beauty are getting brown and crispy. Is that salt burn? They get watered twice each week for 20 minutes and each plant has two emitters. Leaf burn on Majestic Beauty from the reader. A. Whenever you see burning or scorching on the edges of leaves or on the leaf tip it is a sign that the plant is not getting enough water or there are toxic or excessive salts in the soil. However, knowing the number of emitters and how long they deliver water (20 minutes) does not tell me how much water is being applied. Drip emitters are variable in their output depending on the type of emitter. All delivered amounts for drip irrigation are in gallons per hour. Drip emitter at the end of 1/4 inch tubing releasing water at the base of a tree The most common drip emitters cannot deliver more than 5 gallons per hour. So if there were two, five gallon per hour emitters present, the most water that plant would get in 20 minutes is about three gallons. I don’t know the size of this plant but that is not much water in one application to a tree.             Other reasons the plant may not be getting enough water is that the water is applied incorrectly, roots are damaged so the plant can’t take up enough water, the plant trunk is damaged so not enough water moves up the trunk or damaged stems. If amendments heavy in salts were used at planting time these salts can compete for water with the plant causing leaves to scorch or the types of salts present were or are toxic. This time of year (March) watering twice a week is not too often provided the soil is draining adequately and not staying wet between irrigations. I would visually inspect the tree for damage to the trunk and limbs. Move the drip emitters away from the trunk about a foot to 18 inches and add an extra emitter. Four drip emitters were installed on this newly planted and staked tree with rock mulch. The emitters should be placed on the outside of the the rootball and not next to the trunk. If these drip emitters were five gallon per hour emitters and the irrigation was run for one hour then this tree would get 20 gallons each time it is watered which is about right for a 24 inch boxed tree. and place them in triangulation around the trunk. In the meantime flood the area around the tree once a week for three weeks with a hose so you can flush excessive salts and solve the lack of water which solves A and B and F and may help in G Most likely the roots were not damaged unless the water was not draining

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Rootspread of Landscape Trees in the Desert Controlled by Water

Leave a Comment / desert soils, how far do roots grow, rootspread and water /

Q. If I have very mature shrubs (over 5 years) like  abelias etc. and keep it shaped to about 3’x3′. Will the “mature’ root system stay within the canopy for watering purposes or extend out due to age and need more water? A. The roots will stay where the water is and go not much further. You can contain the roots of trees and shrubs just with the placement of water provided the soil around it is dry. This is the wetted pattern of a plant growing on a slope during the winter months. I took the picture to show you how applied water follows the laws of gravity. The wetted pattern only shows a portion of the soil actually wetted by the drip emitter. The actual wetted area the roots can use extends probably a foot beyond this surface wet spot in all directions, further on the down slope side. Always put drip emitters UPSLOPE of a shrub planted on a slope so the water moves downslope through the root system. But you should try to water at least about half of the area under a plant’s canopy. If plants are isolated from other water sources in the desert, roots will stay close to the water source and not go much further. The wetted surface of the soil gives you a much smaller idea of the true spread of the roots.

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Kaki May Not Give HIgh Quality Persimmon Fruit in the Desert

Leave a Comment / budding persimmon, grafting persimmon, kaki a good choice for rootstock, persimmon selection for the desert /

Q. When will be a good time to transplant a Kaki persimmon tree and will it do well in Las Vegas? A. I am curious why you want to use the kaki species of persimmon. It is considered to have inferior fruit to improved varieties of persimmon. It will do as good as the other persimmon. All persimmon are not a desert tree so it will need to be planted in a spot less damaging than for cactus and other desert suitable plants. East side or north sides are best. Keep it away from reflected heat and light. Soil should be heavily enriched with compost at planting and a wood surface mulch should be used 4 to 6 inches deep keeping it away from touching the trunk. Kaki is used for rootstock for other better varieties of persimmon. Fuyu, Giant fuyu, Chocolate, etc have superior fruit. I contacted my friend Tom Spellman from Dave Wilson Nursery for his comments. Comment from Tom Spellman at Dave Wilson Nursery. Bob, Kaki is a common term used for persimmon. D. kaki is used as a rootstock as well as D. lotus. All growers in the United States choose to use lotus as it is much easier to bud onto and, contrary to some opinion, much more comparable and long lived. We have experimented with kaki rootstock several times and the bud stand is never good enough to even begin to make a profit. You know how persimmon does in the Nevada desert. You must protect it from the most extreme heat and sunburn.

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