Xtremehorticulture

Xtremehorticulture of the Desert

Is There Anything That Will Control Squash Bugs?

Leave a Comment / how to control squash bugs /

Q. I live in southern Utah “Cedar City” and put in a garden that is 15×120 each year. Over the years the squash bug infestation has become worse and worse. I used Sevin insecticide in both the powder and liquid spray form and tried a product called Bug B Gone. All this seems to help some but the bugs always come back. Last year they got so bad that I got a bottle of Sevin that you connect a garden hose and sprayed the entire garden but they still came back. Brave squash bugs out in the open on this squash plant A. The biggest problem with gardens and squash bugs is that people don’t get on top of the problem early enough. They wait until they see squash plants, melons and pumpkins start to wilt before they go and investigate the problem. When they then check under the leaves they see hundreds of them in all stages of development and by that time it is normally too late. Squash bugs begin to infest these types of plants when they are very young. You can have a fairly large population feeding on the undersides of leaves and not see any reaction by the plants until the numbers are very high. Squash bugs with yellowing and browning starting from their feeding It is important to check the leaf undersides two or three times a week. Once they are spotted it is important to get rid of them by handpicking or a cordless vacuum if you are squeamish about them. Soap and water sprays will work but they must be sprayed on the undersides of the leaves, not the tops of leaves, for it to work. Soap and water sprays like insecticidal soaps are effective but the bugs must be sprayed with the soapy solution directly for it to work. The soap sprays do not leave enough of a toxic residue behind to give any long lasting control. So sprays must be quite often during the week. Mama and babies and the yellowing from feeding damage Some people have reported some damage to plants from soap sprays made from dishwater liquid detergents so it is best to buy an insecticidal soap like Safers or make sure the soap you use is safe to spray on plants. Other insecticides like Sevin are also very effective but they are also toxic to bees, not a good mix with plants that are in flower. If you lay boards or thick cardboard in the garden they will congregate under there and can serve as a good trap that where you can get rid of them by hand. This does not substitute for checking under the leaves. Melons and squash that vine can also be trellised and when they are trellised they are easier to check, spray and hand pick and seem to not get infestations that are as heavy as those that lay on the ground.

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Determining the Correct Sized Drip Emitter

Leave a Comment / drip irrigation, how to determine the right sized drip emitter, which drip emitter to use /

Q. The landscape people are into variable drip emitters and think I am a little looney sticking to drip emitters.  How do you determine how many gallons to give large trees like African sumac, bottle trees, Swan Hill olives, Yew pines and chaste trees? A. No one puts it in gallons because there are too many different manufacturers and rates of deliveries of different irrigation emitters and sprinklers. These can vary from 1/4 gallon per hour (1 liter) to five gallons per hour. Then there are the types that are variable and can be twisted open to give you more or fewer gallons per hour. Drip emitters color coded for gallonage You have to figure make the conversion and convert it yourself. It is not terribly hard to do, particularly in drip irrigation. Each emitter is labeled or color coded to the gallons per hour that they emit. The hardest emitters to figure out are the types that can be adjusted (variable) to different amounts of water. Many of these are adjustable between 0 (shut off) to 10 gallons per hou It seems simple. You just twist the emitter open and it delivers more gallons per hour. But in actuality it begins to defeat the purpose of drip emitters: precision. Also many of these variable flow emitters are not pressure compensated. If it is not pressure compensated, then opening one emitter and allowing more gallons to flow can affect the number of gallons on all the other non pressure compensated emitters on the same line. Variable drip emitter This can mean you have to twist open or twist close each emitter along the same line perhaps multiple times to get the flow that seems to be appropriate. Not only that but these variable output emitters frequently emit so much water so quickly at the higher settings that it results in water puddling and running off to low spots. This is exactly contrary to the reason we should use drip emitters. With many different types and sizes of plants along the same line the next difficulty for most people is to figure out what size (gallons per hour) to match up with each plant along the line. So this is how I do that. The first thing I do with an emitter line attached to a single valve is determine how many hours or minutes the valve will be left open for watering. Frequently for drip irrigation the shortest time is one hour. Flag emitters easy to clean and color coded “Yikes” you might say because most people want to irrigate fifteen or twenty minutes. The problem with these short irrigation times is that it may force you to use the variable output emitters. Or it results in water applied so rapidly it does not penetrate the ground and instead runs and puddles somewhere else. Start with a minimum of one hour. In some cases you might water for two or three hours on a single line. What difference does it make? You are not standing there with a hose and it can take all night if you want it to. There is no problem watering at night with drip irrigation. Let it soak long, slowly and deeply. Try to use at least two emitters per plant in case one plugs. Here is the one hour example. One gallon plants, give them one gallon per hour (two, half gallon per hour emitters). Five gallon plants give them three to five gallons per hour (two, two gallon per hour emitters or three, one gallon per hour emitters). Fifteen gallon plants give them 8 to 15 gallons per hour (two, four gallon per hour emitters or two, five gallon per hour emitters or three, three gallon per hour emitters, etc.) Distribute the emitters under the plant canopy, one foot from the plant with distribution tubing and secure them in place with rock mulch or stakes to hold them in place. Emitters should be above the mulch so you can check them for plugging. Plants that are spaced closely together can and will get water from each other. Does this help a bit?

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When to Divide Lily of the NIle

Leave a Comment / agapanthus how to divide /

Q. When is the best time of year to divide a Lily of the Nile? Please tell me how to do it. I have 1 that is about 10 years old and it isn’t looking very good. A. The soil might be getting exhausted. They do like a fairly rich soil and if you do not apply compost to them frequently the soil can get mineralized and they will begin to look peaked (yellowing with little growth or poor flowering). They like organic mulches and do not like rock mulch at all. Lily of the Nile has a bit different rhizome than some other plants. In the trades they refer to them as bulbs but they are not bulbs at all. It is late (April) to do it now but you can divide them in early spring (February) or fall around October 1 to 15. You would wet the soil and lift them with a shovel being careful not to damage the “bulb”. After lifting them, wash the bulb (looks like fingers) with a strong stream of water from a hose and get the mud off of them. Cut them apart with a sharp knife. It is best to not divide them into too many small “bulbs” but you should have two or three growing points in each “bulb” that you replant. Wash the cuts and dust them with a fungicide like Thiram or allow them to air dry in the shade before you replant them. Replant them with the buds (in the spring you may see a bud but in the fall it’s the end with the leaves) pointing up and about two inches deep. They can be planted about 18 to 24 inches apart with soil amended with compost and a starter fertilizer.

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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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