Newsletter High on the Desert Cochise County Master Gardener

Vol. 26, No. 8 August 2015

The University of and U.S. Department of Agriculture Cooperating

The Virtual Gardener—Watch Out For Imazapyr! The weedy season is upon us. ingested) is quite high at greater than Besides picking zucchinis and tomatoes, 5,000 mg per kilogram of body weight. most of us are in the weed eradication This means that a human weighing 130 business. Some of us scrape, some pull, pounds would have to consume 300,000 and many spray. This month I want to mg (2/3 pound) to be at that risk level. discuss an herbicide chemical called Highly unlikely. The chemical also has imazapyr. This chemical is a very no known carcinogenic or genetic effects effective non-selective herbicide and a for humans. component of many commercially Tests also indicate low toxicity to available herbicides. It must be used with birds, fish, and other mammals. In fact, extreme caution. the Environmental Protection Agency has rated the chemical as safe for use in aquatic environments, including riparian Inside this issue: areas and coastal waters. Monsoon Rains 2 Imazapyr works to kill by Cuttings “N’ Clippings 3 interfering with their ability to synthesize This Month in the Garden 3 certain necessary proteins and is very Ready, Set . . . Grow! 4 effective. It is readily absorbed by both August Reminders 4 and roots and accumulates in the At a Glance Box 5 Be sure to read the list of ingredients active growing tissues (meristem) of Apache 5 on the label of the herbicide before you plants where it does its deadly work. As WW/MG Xeriscape Tour 6 buy it. mentioned, it is non-selective and works The danger of this chemical is not so equally well to control grasses, broadleaf much to humans. It can cause eye weeds, and even woody plants. And it irritation and skin redness, rashes, and has a long half-life in the soil (69-125 even swelling, but these effects are days), making it perfect for long-term basically superficial. The LD50 (the weed control. So what’s the problem? amount that is estimated to cause death 50 percent of the time, if the chemical is (Continued on Page 2)

Cochise County Cooperative Extension www.ag.arizona.edu/cochise/mg/ 1140 N. Colombo, Sierra Vista, AZ 85635 450 S. Haskell, Willcox, AZ 85643 (520) 458-8278, Ext. 2141 (520) 384-3594 P AGE 2

(Continued from page 1) “You should not use it within three The basic problem is that yards of any plants you don’t want to imazapyr is too effective and too kill—your yard, your neighbor’s non-discriminating. It doesn’t dis- yard, and his neighbor’s yard!” criminate between good plants and Research has shown another bad plants but kills them all. Of interesting characteristic of imaz- course, other herbicides will also apyr. The roots of some legumes that kill your ornamental and food have been exposed to this herbi- plants but most have limited half cide—mesquites were specifically lives in the soil so you only have to mentioned—may exude the chemi- Monsoon Rains be careful not to spray them cal. This means that other plants Have Hidden Benefits directly on the plants you want to whose roots touch the roots of keep. One of the most popular mesquites that have been exposed to for Plants herbicides, glyphosate, is almost imazapyr may be poisoned. instantly neutralized when it hits The moral of this article is that you (Editor’s Note: Adapted from article the soil. It is only effective when must always READ THE LABEL. of the same title by John Begeman in sprayed directly on plants. Another If you don’t recognize the name of a the September 1998 Cochise County popular herbicide, 2-4-D, has a chemical in the herbicide, look it up Master Gardener Newsletter.) limited lifespan and limited on the internet before you buy it. The loud crackle and thunderous mobility in the soil. Although its And once you have brought it home, boom of lightning is now a familiar effect lingers longer than glypho- carefully follow the instructions on sound as our monsoon is in full sate, they are still fairly restricted. the label when you apply it. swing! Every time lightning strikes, Because of its chemistry, the For additional technical details nitrogen in the atmosphere is com- mobility and persistence of imaz- about imazapyr, check out this bined with hydrogen or oxygen to apyr in the soil is sensitive to soil webpage. form ammonium and nitrate, two pH (acidity). In acid soils, it is Until next time, happy surfing! forms of nitrogen. The nitrogen relatively quickly adsorbed and its Gary Gruenhagen, Master Gardener then goes into solution in atmos- mobility limited. In alkaline soils, [email protected] pheric moisture and is washed to such as we have here in Southeast- the ground in rainfall. Plants then ern Arizona, imazapyr is not absorb nitrogen from the ground quickly adsorbed by soil particles, and utilize it for growth. Since it is allowing it to move greater a key constituent in chlorophyll, the distances—both horizontally and green pigment of plants, nitrogen vertically. It is this ability to causes a greening of the plant. penetrate deep into the soil and Physicists estimate that roughly make contact with tree roots that 250,000 tons of nitrogen are pro- makes this chemical a threat to duced by about 1,800 thunder- trees. The instructions on the storms that occur on Earth every container for one popular herbicide day. Our summer thunder storms containing imazapyr say never to The U of A Water Wise Program (520) 458-8278, Ext. 2141 can release significant amounts of apply the herbicide to within twice nitrogen for plant growth here in the width of the drip line of a tree Southeast Arizona. That causes a you don’t want to kill. significant part of the greening of As one University of Arizona Cochise County Master plants we notice after a storm. Horticultural Agent once said Gardener Newsletter Editor about an herbicide containing John Begeman, former Horticultural Carolyn Gruenhagen Extension Agent for Pima County imazapyr:

“Give weeds an inch and they’ll take a yard.” P AGE 3

This Month In the High Desert Garden— Cuttings ‘N’ Clippings Time Is Running Out . . . The August Cochise County (Editor’s Note: This article written on your tree or shrub three times a Master Gardener Association by Bill Schulze was adapted from a week really doesn’t do much good. meeting has been moved to August 2011 article published in the And, with the advent of the rains, Thursday, August 20 from 2:00— Sierra Vista Herald.) weeding becomes important. Use 4:00 PM. They will be joining with mulches to suppress weeds or pull the Sierra Vista Area Garden Club It’s pretty safe to speculate that the weeds by hand while they’re at their regular meeting location in August will be a whole lot like still small. Don’t give them a the lecture room of the County Con- July here in the high desert. With chance to go to seed or your weed stables Building at 4001 Foothills any luck, our monsoon rains will headaches will just be multiplied in Drive, on the northeast corner of continue—let’s hope they’re gen- the months and years to come. Re- Foothills and Highway 92. Dr. Pau- tle—and the daytime highs will member that if you give a weed an la Kahn-Rivadeneira, Assistant Pro- be in the 80° and 90°F range. As inch, it’ll take a yard! fessor & Extension Specialist, Food such, continue to plant annual When mowing grass, leave it 3-4 Safety and Wildlife, Department of flowers such as zinnias, cosmos, inches long. Cutting it too close to Soil, Water, & Environmental Sci- vincas, and marigolds, and at least the ground stresses the grass, espe- ence, University of Arizona, Yuma cially in hot weather. It also results Agricultural Center will be talking in a poor looking lawn. As an alter- about Critters in my garden: Food native, think about replacing your safety risks and humane solutions. thirsty grass lawn with a more water Check the web site for the next -use friendly landscape. It’s hard to scheduled event or contact Valerie argue against spending less time at: mowing, or a lower water bill! [email protected] Keep an eye out for insect pests. I  The Master Gardeners have re- like to use insecticidal soap or hand turned to the Sierra Vista Farmers picking (I know, yechhh!) to control Market on the first Thursday of insects. I recommend buying insec- each month. ticidal soap, whether pre-mixed or some warm season vegetables. The next free Water Wise in concentrate form, from a nursery. It’s most likely a bit too late to presentation will be Saturday, Au- Concentrate is much cheaper in the plant tomato plants, although ear- gust 8 from 9:00—11:30 AM in long run. If you do choose to use ly varieties such as ‘Early Girl’, the University of Arizona South insecticidal soap concentrate, mix it ‘Patio’, and many cherry types PMR. Jan Groth, Master Gardener, carefully according to label instruc- should still yield decently before will speak on Plant Now: 20 Most tions. There’s a fine line between frost strikes. If you haven’t plant- Successful Landscape Plants. Late insecticidal soap and herbicidal ed your peppers, chiles, winter summer to early fall is the BEST soap. I nearly killed a couple of my squash, and melons by now, it’d time to plant most landscape plants. wife’s rose bushes years ago when be best to hold off until next year. But what to plant? Successful land- the soap solution I made was not Beans, cucumbers, and summer scape plants, along with design, only made from regular dish soap squash remain good choices and planting, and care will be discussed. but was a bit too strong. Realize, there’s still plenty of time to grow Plants will be for sale following the too, that you must spray the soap more zucchini than any one fami- talk. Check the Water Wise 2015 solution directly on the insects. ly can possibly eat. schedule on their web site: Soap solutions work by suffocating Continue to give supplemental waterwise.arizona.edu insects with a soap film. An insect water as the monsoon rains dic- For more information contact Va- crawling over a sprayed won’t tate and remember to water slow lerie at: be killed. and deep. A fifteen minute drip [email protected] Bill Schulze, Master Gardener

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baking soda with two teaspoons horticultural oil with one gallon Ready, Set . . . Grow! water—may add about a teaspoon of a surfactant (such as dish soap) “Fungus Amongus!” If you Why are they so hard to get con- to help it stick. haven’t seen any yet, it will not trol of once they are “partying” all  Copper compounds (a.k.a. be long. It has been a blessing to over your squash and roses? Bordeaux mixture) receive so much consistent rain These fungi don’t necessarily  Copper soap fungicides lately. Some areas (e.g., Sierra need a partner to reproduce. They  Neem oil Vista) are, of course, seeing it have the capability of reproducing  Potassium bicarbonate more than others, which is the sexually and asexually. Plus, once  Sulfur dust usual nature in our desert cli- spores are produced, wind, rain,  Lime sulfur (calcium polysul- mate. But the conditions are per- irrigation water, tools, animals, fide) Only use during dormancy. fect for fungus to multiply and and insects can disperse them over Caution: it’s caustic—Sunset spread. All sorts of fungus can great distances and quickly. This is Western Garden Book, 2001 run rampant during this time: why it is a great battle to get them Notice throughout this article I powdery mildew, anthracnose, under control and why it is advised referred to only pathogenic fungi. root rots, sooty mold, rust, and that preventative measures be used As many of you know, there are verticillium wilt just to name a from the get-go. Once the disease more beneficial “fun-guys” that few. I don’t mean to sound like a is present it is usually too late to live synergistically with plants and “downer,” but it’s true. spray anything that will control it. actually help them grow, but more I was recently reminded by a So, what are ways we can pre- about that another time. Happy gardening, friends! visiting friend and plant path- vent these pathogenic fungi? ologist that, “Of all the diseases There are organic and synthetic Joshua Sherman, M.S. you will get called on to identify fungicides available on the market, Commercial Horticulture Area Agent

it is almost always 90% of the and if you are organic, be sure to Note: Mention of commercial prod- time, fungus.” Pathogenic “fun- check the Organic Materials Re- ucts or trade names is made with the guys” (see what I did there), view Institute (OMRI) site for any understanding that no endorsement is spread by spores, which can be listings first. Here is their website: implied and no discrimination is in- thought of as seeds of the fungi. www.omri.org/omri-lists. tended by UA Cooperative Extension. However, as we know, these I must say one thing about spray- spores cannot be seen by the na- ing fungicides here…DO NOT ked eye, so you may have fungus spray the same fungicide over but just don’t know it. When the and over again! I really hope to conditions are right, these spores get this point driven home. Be- germinate and form mycelia cause of the quick life cycle of with specialized structures used these fungi, they become resistant to penetrate plant tissue and live to a chemical, which is also why it from its resources and nutrients. must be applied correctly, accord- It is only when these mycelium ing to the label, and with complete are so vast that the fungi be- plant coverage (also, read the pre- comes visible to the naked eye cautions for protecting you). for us to see the symptoms left It is best to have a diverse pro- by our “not-so-courteous” gram with different preventative  Keep pulling the weeds guests. Symptoms we frequently controls being applied over the  Prolong annuals by dead- get asked about like galls, can- length of the season. (Side note: heading spent flowers kers, leaf spots and curls, blight, This is what is done in commercial  Plan your spring wildflower and root rots can be caused by orchards and row crops.) garden both fungus and bacteria. How- Here is a list of some natural fun-  Watch for nutrient deficien- ever, when the symptom is mold, gicides and control mixtures to get cies, sunburn, salt burn, over- smut, sooty mold, or powdery you started: watering, & insects mildew it can only be a patho-  Sodium bicarbonate (yep, bak-  Fertilize genic fungus. ing soda)—Mix two teaspoons P AGE 5

At a Glance Box Given its honeysuckle-like ap- pearance, I was surprised to learn It’s a Bloomin’ Cochise County Native Plant of the Month that Apache plant is an aster. Its

Plant: Apache plant, curious flowers don’t exhibit the Description: Large shrub. Deciduous. ’s typical sunflower- Blooms: White flowers, mid-spring like shape. Instead, the irregularly- Use: Excellent Xeriscape plant shaped ½ inch white flowers, with Culture: Not picky. Hands-off! one to five rays (“petals”), and Learn more: Cochise County Herbarium, www.cochisecountyherbarium.org only a few disk flowers are clus- For an in-depth article, see below. tered at the tips of the stems. At- tracting numerous pollinators, it Article by Karen LeMay, Guest Author appears that they provide a lot of Founder of Pollinator Corridors Southwest nectar. Our home adjoins the Coronado Apache plant Apache plant is native to National Memorial area, and I Guardiola platyphylla northern in and have made many trips along the , and Cochise, Santa road to Montezuma Pass, observ- I first discovered Apache plant Cruz, Pima, and Gila Counties in ing the flowering plants that thrive (Guardiola platyphylla) during a Arizona (USDA Plant Database there. This has helped me select naturalist’s walk led by Vincent http://plants.usda.gov/). The plants for our habitat garden, as Pinto in the Coronado National other thirteen Guardiolas are my mission has been to use as Memorial. It wasn’t the numer- Mexican. Apache plant’s natural many local natives as possible. ous tiny white flowers that habitat is upland areas, growing When I discovered that Desert caught my attention—it was the on rocky slopes in oak-juniper Survivors in Tucson interesting leaf shape and plant’s canyons. It can reach one meter (http://www.desertsurvivors.org/ form. Since then, I’ve learned in height. I haven’t seen any that plant-lists.html) propagates and how valuable it is for native pol- large in the wild, but there’s one sells Apache plant, I purchased linators. at Tohono Chul Botanical Gar- three. I planted them in full sun dens in Tucson that’s even taller. and partial shade and after several I learned that Apache plant years in the ground, all are thriv- was named after a Spanish bota- ing. During one especially mild nist, and that Guardiola is a com- winter they were evergreen, and mon family name in Spain, but were the earliest plants to flower no more about its namesake. I in our yard, offering nectar to a have never learned why it’s variety of spring pollinators. Dur- called Apache plant. If any of ing more typical winters, the you have further information plants are deciduous, but quickly concerning its common name, leaf out from the base and flower please share it with me. I did by mid-spring. read that in Mexico, a tea made In our yard, we have observed a from the leafy stems is used to number of bees nectaring on treat cattle with skin infections. (Continued on page 6)

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Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Jeffrey C. Silvertooth, Associate Dean & Director, Economic Development & Extension, College of Agriculture and Life Sciences, The University of Arizona. The University of Arizona is an equal opportunity, affirmative action institution. The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities. The information given herein is supplied with the understanding that no discrimination is intended and no endorsement by Cooperative Extension is implied. Any products, services, or organizations that are mentioned, shown, or indirectly implied in this publication do not imply endorsement by the University of Arizona. P AGE 6

(Continued from page 5) an excellent choice for a wildlife/ plant that blooms several times a Apache plant, including the sweat pollinator habitat garden. Either year, each blooming period bees, Augochlorella and Halictus, way, it has many benefits. A local providing nectar for a different set the tiny carpenter bee, Ceratina, native, it is adapted to our nutrient- of native pollinators. poor soil, extremes in temperature, It seems like once you’re intro- Carpenter bee , Ceratina dry windy weather, and rainfall that duced to a plant, you begin to see is absent for months or comes in it everywhere. This spring I no- downpours. It doesn’t require soil ticed many volunteers of Apache amendments, pesticides, or pruning, plant along the five mile Coro- and makes little demand on our nado Memorial Drive (off of Hwy scarce water resources. In the wild 92 in Hereford) that leads into the or the garden, it is a nicely shaped National Memorial and visitor’s center. Maybe they were there Eastern Tailed-Blue before I discovered them, but now I’m well aware of them and will look for new pollinators at their flowers. and honey bees. Butterflies on its Karen LeMay, Guest Author, Found- flowers have included Grey Hair- er of Pollinator Corridors Southwest streak, Marine Blue, and the lo- (a new nonprofit supporting native cally uncommon Eastern Tailed- plant habitats and their pollinators). Blue. For info see: Apache plant makes an attrac- www.PoCoSouthwest.org tive specimen plant in a formal Photos and technical advice from setting and, as noted above, it’s Robert A. Behrstock

August 29, 2015 10:00—2:00 PM Water Wise/Master Gardener 18th Annual Xeriscape Tour!

Don’t miss this exciting tour!

For a short video tour of an amazing 5 acre cactus/succulent/rock sculp- ture garden on the tour, Click here.

Contact the University of Arizona Cooperative Extension for information and maps. 348-8278, Ext. 2141 Photos and video by Carolyn Gruenhagen [email protected]