Desert Horticulture Podcast: What HOA's Need to Know to Lower Community Costs

HOA's have a presiding Board that looks after community costs and instigates rules. If you want to lower community costs, here is what to do.

Roses Don't Like Las Vegas' "Winter"

Roses Hate Las Vegas Summers

            It's summer. This is the time of year when garden roses struggle. Summer is their "winter". As the temperatures get hot, roses stop flowering and the leaf edges turn brown and scorch. The month and week it stops flowering depends on their “landscape exposure” (which magnetic direction they are facing in the landscape), how the soil was amended where it was planted, the variety planted and its overall health.

If roses are not taken care of properly they will look pretty scraggly during the summer months in Las Vegas. This rose has some salt issues due to a lack of water to flush the salts from the soil and a lack of good soil preparation for good drainage.

Rose Family Plants Don't Like Rock

            Some plants don’t grow well in rock and roses are one of them. Nearly all landscape plants in the Rose Family (think Photinia, pyracantha, strawberry, Carolina cherry laurel, and most of our favorite fruit trees) like soil improvement and a moist environment when planted in desert soils. The number of native Mojave Desert plants in the Rose Family is very limited. That tells you something about the desert environment and the Rose Family.

This landscape photinia lost its leaves during the winter mostly because of its poor health. Plants in the Rose Family need soil improvement at the time of planting and surrounded by organic mulch, not rock. 

Roses Like Amended Soil

 The most favorable environment for garden roses in the desert is soil amended with compost at planting, six hours or more of morning sun, organic mulch on the soil surface (like woodchips) and moist soil. Garden roses will NOT do well the first year after planting if put in the wrong location, the soil is amended poorly and not watered correctly. They will begin failing in 3 to 5 years if surrounded by rock.

Apply Fertilizers to Roses

            Applying the right kind of fertilizer at the right time is only part of the success equation. Applying a rose fertilizer once in the spring is adequate, three times during the growing season is better and it can get complicated from there with fertilizer favorites and soil amendments if you are a rose enthusiast.

Select Roses that Like the Desert

            Some roses perform better in the hot desert than others. Consult Cooperative Extension or the Weeks Roses wholesale website for suggested recommendedvarieties for the desert when buying or replacing. Roses last 20 years or more if properly selected, planted and maintained.

Coconut Palm Not for Las Vegas Permanently

Q. My son gave me a small coconut tree in a pot for Mother’s Day. I waited about 2 weeks before I planted it in a bigger pot. I’ve put it on the patio that faces west so it’s hot in that location. How can I help this coconut thrive in the desert?

A palm is a nice Mothers Day gift but you cant keep it unless you are in south Florida or live in the tropics.

A. You can’t. This isn’t the tropics. It can handle our heat but not our cold temperatures.  It can’t thrive here even if it survives the freezing temperatures of our winter. The biggest problem it faces, besides surviving the winter, are the cool spring and fall months. Extended periods of cold below 45° F causes permanent damage to a coconut palm.

This coconut fell from a palm into this water in the Philippines. It germinates easily if temps are warm enough.

            Coconut palm is truly one of the tropical palm trees. You will find coconut palms in Hawaii and southern Florida but it’s even too cool for coconut palms in Southern California so we seldom see them there.

Keep Dry Fertilizer Dry

Q. I have 50-pound sacks of 16-16-16 fertilizer in plastic bags. Somehow moisture got in the bags and the granules are wet enough that the fertilizer doesn’t drop through the spreader anymore. I live in a wet climate. What can I do to dry this fertilizer out?

Granular fertilizers like this Arizonas Best Citrus Fertilizer will last for years as long as it stays dry.

A. All sorts of scenarios are dancing through my head. Dry fertilizers in bags are meant to stay dry. If dry granular fertilizers stay dry, they are never hard to use. Getting wet is the one thing that can ruin a dry fertilizer specifically designed for use in spreaders that rely on some sort of a hopper (where you pour the dry fertilizer) for spreading it.

Fertilizer spreaders like this rotary spreader can handle a little bit of moisture in granular fertilizers, at least better than a drop spreader can. Its not as precise as a drop sgreader but can get the job done well if you are careful how you apply it.

Drop Spreaders are for Lawns

            Drop spreaders rely on specifically sized granules so it’s settings can be adjusted properly for a precise application rate. They are usually used for applying fertilizers to lawns. You have lost the drop spreader application option for that fertilizer. Chalk it up to “lessons learned” and buy a different bag of lawn fertilizer. This time get a “true” lawn fertilizer like a 21-7-14 and not 16-16-16. The “ideal” lawn fertilizer contains less phosphorus like 21–7–14 with half of its nitrogen (the first number) available in a slow release form.

Sometimes granular fertilizers are blended together with other fertilizers to get a fertilizer with the right numbers on the bag. Here is 21-0-0, aka, ammonium sulfate, which is 100% soluble in water. It has 21% nitrogen in the fertilizer bag. The rest is sulfur, hydrogen and oxygen (79%).

No Weed n Feed and Chunks

            As long as this fertilizer was not a “Weed N Feed”,  use it for other landscape plants, as a compost starter or even in a raised vegetable garden. In desert climates, spread the moist fertilizer out and use the sun to dry it. After drying, the fertilizer will dry into “chunks” that must be broken small enough to be used. Breaking it apart also creates some powder. You could still use a rotary spreader provided the fertilizer granules are dried and broken small enough to use its hopper or even apply it by hand. 

This 16-16-16 is a complete, all-purpose fertilizer with nitrogen, phosphorus and potassium. Use it once a season but no more than that because of the high phosphorus content.

Soluble Fertilizers Dissolve Quickly

            Fertilizers like 16–16–16 are made by mixing two or three fertilizers, with similar sized granules, together. The nitrogen granules in this fertilizer is probably the first to dissolve when it becomes moist . The dissolving of these nitrogen granules “glues” the other granules together into “chunks”. Breaking these chunks apart creates a white powder. You can use this powder to make a liquid fertilizer.

Another example of a lawn fertilizer because it has a low phosphorus content (middle number). It would be better if the last number, potassium, was a bit higher.

            Use no more than 1 to 1½ tablespoons of this powder dissolved in each gallon of water. This solution of water and fertilizer can be used to spray the leaves. This “liquid fertilizer” can also be poured safely on the soil very close to the plants. The remaining granular fertilizer can be used just like any 16-16-16 fertilizer. It won’t be 16-16-16 anymore but it will be a fertilizer probably high in phosphorus and potassium.

Traditionally water soluble fertilizers (intended to dissolve in water first) are made to be put in water but they should still be dry until they are used. This water soluble fertilizer made by Grow More is called "Super Bloomer" because it has a large amount of phosphorus (middle number) to promote flowering and rooting.

            Don’t throw this bag out. Use the fertilizer in it. It’s just going to take a little bit of work to get into a usable form.

Best Branch Angles are 45 Degrees from Horizontal (or vertical)

Q. This is the second year for my Santa Rosa plum.  I attached some garden trowels to some of the main branches to open – up the tree to a vase shape.  Is this a good idea?

Weights work good for opening up or spreading open a fruit tree like this Santa Rosa plum growing in Las Vegas. Limb spreaders are faster.

A. Somehow I feel like this was a setup. Yes! If you follow me long enough you know I like to see flower and fruiting plants without their branches growing at 45° above horizontal.  Many types of plum have  narrow crotch angles and their canopy needs to grow more openly.

Some trees grow upright even if they aren't supposed to like pears, many plums, Asian pears and their ornamental counterparts. Good crotch angles form a "U" when they are strongly attached to a limb or trunk. Weak crotch angels form a "V" when the angle is too weak and the limb will split when it gets some weight on it. The branch in the back is growing straight up. No, no, no. Get rid of it now! (and that little one in front, too!)

            Branches growing at 45° angles produce an optimum balance between growth and flower or fruit production. Branches growing horizontally or downward may flower well but don’t grow fast. Branches growing nearly upright (vertical) grow very rapidly but they are slow to flower. The tree intends for this type of growth to give it height. Some trees grow extremely upright (most pears for instance) and the limbs should be spread apart and pruned to outward growth in mid to late spring to slow it down and improve flowering or fruiting.

When young trees or young growth grows too close together and upright, use a limb spreader to push the branches apart for one season of growth.

            Plants don’t care if their limbs are spread to 45° by weights or another method. I prefer to use “limb spreaders” of different lengths (4, 8, 12 and 18 inches). They are faster and less adjustment is needed. You can make them with forked ends out of  one-inch wood lath and even wooden paint stirrers. They should be strong enough to hold branches apart and not break while doing it.

Limb spreaders have a crotch on both ends to help keep the small limb from sliding out. I made this one and it also has a wire brad with the tip cut off to grab the limb better. I now make them without the nail in the crotch. They hold just as well.

            Be careful spreading limbs apart early in the season when they easily split if bent too far. After the new growth in the spring is an inch or two is the perfect time to bend limbs to their proper angle and either a hang weights, use limb spreaders and prune to outside growth to open the canopy wider. After one season of growth in this position they can be removed.

Just Because Its a Cactus Doesn't Mean it Loves it in the Mojave!

            

Some pictures of "torch" cacti in the yard of one of my readers. Great job!

Several questions were sent to me regarding cacti. In general, the most common reason for failure of cactus is watering too often. The second most common reason for cactus problems is because it was put in a hot, bright location when it should be located in a protected part of the yard. The third reason is because the cactus was damaged during our winter cold temperatures and prefers being planted in a warmer climate.

Argentine Giant Cactus (Not yet!)

Automatic Irrigation

            Be careful when putting cacti on an automatic water or irrigation timer. They are watered so infrequently that it sometimes makes sense to water these plants manually with a hose rather than automate it. When cacti begin to shrivel, it’s time to water. When they look plump and firm, they don’t need water.

            If you’ve got lots of cacti and you are using an automatic timer, then run that station or valve when they need water but make sure they have good drainage if you water them automatically (without looking at them). A hose, manual timer and sprinkler also makes sense for larger desert plants.

Watch for winter low temperature damage. Know your cactus!

Water Cacti 12 inches deep

            Medium-sized and small cacti should be watered about 12 inches deep. Large desert plants like a saguaro or Joshua tree should be watered 18 inches deep and have water applied to an area underneath them equal to at least half of their height. Watering a large area under large plants helps keep them stable and keeps them from falling over when the tops get large and heavy. Watering any of these plants too often can cause disease or unsightly growth problems.

Cactus from the Sonoran Desert, like this nopal, may require warmer temperatures when planted in the Mojave.

Your Cactus Has a Name

            Find out the scientific name for your cactus and Google it. Learn where it originated from. Some cacti are native to the southeastern US or higher elevations in other countries. In these locations it was cooler so they will need protection from late afternoon sun in the Mojave Desert. Cacti native to our Southwestern deserts do not. They can handle hot and dry locations. Learn if your cactus should be planted in a gentler landscape location or can handle the harsh ones.

Watering only at the base of most cacti results in blowover with wind and if they get tall like this one in Parker, AZ.

Know Where it Comes From

            Some cacti are tropical or subtropical and get damaged because of our low winter temperatures in the Mojave Desert. Cacti which can handle low temperatures of 20° F or lower probably will not need much winter protection in all but the coldest years. Other cacti which are less tolerant of these low temperatures might, depending on your landscape microclimate and location in the valley.

Controlling Spurge in Vegetables Without Chemicals

Q. How can I get rid of spurge in my vegetable garden?  I have been hoeing it and hand pulling it just about every day, but it appears to be getting ahead of me this year.  I do not use any chemicals in my garden, so that is not an option.

A. Shade. Spurge hates shade. 

What is Spurge?

Spurge is a pernicious weed; it hugs close to the ground when it grows and germinates rapidly from seed it produces in less than 30 days during summer months. It can also grow new roots if it is hoed and left on top of wet garden soil. It must be removed after hoeing since this plant produces seed continuously.

Pepper with horse bedding for mulch.

           Its strengths are how much seed it produces, how fast the seed germinates and its ability to root in moist soil once it’s been hoed. But its big weakness is shade. By that I mean it doesn’t take much to shade it out. If the garden space is full of plants and producing a lot of shade, spurge has a difficult time.

           There are several types of spurge, but I think yours is prostrate or creeping spurge that hugs the ground and makes a tiny drop of white latex when the stem is broken. And of course, lots of seed!

Weeds in onions controlled with horse bedding as mulch

Control Most Weeds with Mulch

           Weeds rob watered light. That’s also their weakness. So, use a surface mulch (½ inch deep) thick enough to shade the soil to defeat it. The application of anything deep enough to keep light from getting to the seed will keep it from growing. 

Horse bedding is nice as a mulch because it decomposes quickly when its wet.

           Apply this surface mulch after planting or the after the seed is up. Garden mulch includes horse bedding, straw, paper (sheets, strips or shredded), cardboard, or anything else that blocks light from reaching the seed.

           Apply this surface mulch early in the season and hoe the soil surface before you put it down. Spurge seed produced during August and later will not germinate until next year. But any older seed still lying on the soil will germinate if it gets water and light. By the way, most annual weeds like spurge (and many others) hate mulch.

WFT Damage on Nectarine Showing Up Now

Q. The fruit from my nectarine had a lot of “sores”; spots with tiny “bubbles” of hardened fluid. Yesterday, early evening, I sprayed the tree with “soapy water” in hopes of improving the problem.

A. Your nectarine fruit has damage from Western Flower Thrips (WFT). That’s one of the reasons I don’t plant too many of them. WFT are hard to control without spraying frequently and soapy water alone won’t do it.  Spraying with Spinosad insecticides weekly until harvest, starting after the flower petals have dropped, has given the best control for me.

           I alternate Spinosad with Neem oil, and soap and water sprays so WFT don’t build resistance to it so easily. Peaches are easier to grow without spraying as much because of their fuzzy skin.

View my posts on this on my blog
Pyrethrin Doesn't Kill Thrips

Fruit Scarring Can Be Prevented

Why are People Friendly Weed Killers Hard to Find?

Q. The class-action lawsuits against the weedkiller “Roundup” claims it can cause lymphoma. Nonetheless, nurseries and big box stores still carry it and even promote it. Isn't there a safer weedkiller? I have been using “BurnOut” made by Bonide which is promoted as being pet and people safe. Why is it so hard to find?

Roundup is carried by many so-called box stores and is still a popular home weed killer. 

A. Products like “BurnOut” are not required to show “efficacy data” before entering the consumer market. “Efficacy data” demonstrates to the regulatory agency that it does what it says it does. It’s a form of consumer protection. There are other companies besides Bonide thatproduce products like these.

EPA's opinion on the safety of Glyphosate.

           There is a list of ingredients considered “organic” and exempt from regulationby the federal Environmental Protection Agency (EPA).  Each state determines if these products should be sold or not through whatever regulatory agency is responsible. Efficacy data may or may not be required by a state.

           “BurnOut” contains citric acid and clove oil as active ingredients. “Roundup” contains glyphosate as its active ingredient. “BurnOut” is a weedkiller that kills by contact. “Roundup” moves inside the plant and is therefore considered a systemic weedkiller. If you look at both labels, “Roundup” must demonstrate that it does what it says it does. This requires EPA registration. There is a federal registration number on the label showing it has met that requirement.

           Citric acid and clove oil are considered “organic ingredients” and do not require the submission of efficacy data to the federal EPA. There is no federal EPA registration number on the “BurnOut” label. Also, PPE (Personal Protective Equipment such as gloves and eye/nose protection) is not required when using products like “BurnOut”. You must wear PPE when using “Roundup”.

Why Not as Available?

           My guess is that products such as “BurnOut”, as well as homemade weed killerrecipes promoted on the Internet, are “contact weed killers”. Whatever plants with leaves you spray, you kill. “Roundup” is a systemic weedkiller that mostly targets grasses but kills many other plants as well and kills the roots as well (systemic) so there is little to no regrowth of perennial weeds.

           Why products like “BurnOut” are not found more? I think a lot of it has to do with the investment the company makes when developing these products, in many cases millions of dollars. I don't believe Bonide does not have to invest as much money and show “efficacy data” when developing and marketing a product like “BurnOut”. I will handle this in more detail on my blog.

Glyphosate vs Roundup vs Health

Removing Root Suckers

Q. Is there a simple way of stopping or preventing the volunteer trees, i.e., new tree growth that suddenly starts growing near the base of original tree? 

Root suckers can pop up at any distance from the tree. They can be used for propagation but remember, as in this case, the suckers are clonse of the rootstock and not necessarily the tree on top (scion).

A. Some plants grow “suckers” at the  base of the plant and others produce suckers, or new growth, a distance away from the plant.  If roots of suckering plants find water and it is out in the open with enough sun, they will sucker. 

Oleander suckering from its base (crown).

This is the difference between suckers arising from the stem or trunk (sometimes called the “crown”) and growing from the roots. Plants that can grow as a bush sucker from the crown. Plants that forms “thickets” grow suckers from their roots. Roots suckers are common to some plums and jujube as well as landscape trees like elm.

Jujube suckering several feet away from its trunk. Several trees have root suckers like Jujube when they must survive fires.

           So far, the only practical way to eliminate them is to slice the roots and remove these plants, roots and all. To prevent diseases found in the soil from invading the tree roots, allow these cut surfaces to heal 24 hours before burying them again.

Recommended Fruit Trees for the Mojave Desert

This list was previously put on my blog years ago and I have been asked about updates. The varieties listed here were tested in North Las Vegas with at least five trees per variety for at least 5 years before they were given a rating and the "green light" for planting. Some didn't make it, either because of winter cold temperatures (citrus, Mexican nopal cactus), possible low humidity problems (sweet cherries and 'Hachiya' persimmon) summer high temperatures (filberts, rhubarb), and poor growing conditions (filberts, rhubarb, blueberries, some blackberries, raspberries). 

Just because they didn't make it in North Las Vegas, try it in your microclimate. They might work and please let me know. Give them at least three growing seasons (preferably 5) before you claim a winner.

 

Citrus does grow in Las Vegas. It just depends on the microclimate of where its growing.

I would like to thank Dave Wilson Nursery (particularly Tom Spellman and Ed Laivo (formerly at Dave Wilson and now at Burchell Nursery) for supporting this project. About 95% of the fruit trees planted were donated. I would also like to thank Tony Valenti , Owner of First Choice Tree Service for believing in my project enough to donate woodchips to use as a soil mulch when local tree companies were against it. They donate woodchips to the University Orchard still in 2020. which is then donated to the community through the Community Mulch Pile.

Community Mulch Pile at the University Orchard in North Las Vegas. There is a second community mulch pile located south of McCarren Intl. Airport. Call 702-257-5555 during the week and get the details.

What is a Microclimate?

Microclimates in landscapes can have different temperatures during the summer or winter (hot walls, shade, freezing temps), humidity (lawn, pool, fountain), sunlight (reflected glass), differences in wind (channeling between buildings) and all these affect plant performance in the desert. Plants do best when everything is still, plenty of sun (but not too much), temperatures
warm, and humidity moist.

Citrus

Citrus include kumquat, lemons, limes, oranges, grapefruit and others. By now you should know that kumquat is probably the most cold hardy of the group, followed by Myers Lemon, Grapefruit, and others. Citrus is not included here because we lost the citrus to low winter temperatures (below freezing weather) before the five years was up. However, in some locations around Las Vegas citrus was thriving. At another location, the same thing happened or they were heavily damaged by the winter cold. So be careful planting citrus here.

The second problem with some citrus are January, February and other late spring freezes. These freezes eliminate some or all of the fruit coming from citrus flowering then.

Low Humidity

Another characteristic of the Mojave Desert is its low humidity. Very low humidity. This is a problem for some fruit trees. Sweet cherries and 'Hachiya' persimmon also were not listed, because they seldom produced much fruit unless there were spring rains. Yet in some locations in Las Vegas sweet cherries produced every year! I think it was because of the low humidity. Residences with lawns or a swimming pool close by produced fruit. Some tropical species also have problems with fruit set at a humidity lower than 30%. It is believed to happen because of the drying of pollen.

Go to my fruit tree list (former blog post)

Request a copy of my list (email)

Peach and Apricot Production at Orchard at Ahern

This is the current (2020) production coming from peaches and apricots at The Orchard at Ahern. The Orchard at Ahern is located between Bonanza and Washington off of Clarkway. There are about 3000 fruit trees planted in this 8 acre orchard only 1 1/2 miles from the Las Vegas Strip.

The Orchard at Ahern is a 3000 fruit tree orchard located on Ahern property only 1 1/2 miles from the Las Vegas Strip.

Apricots pruned for height control spaced at 10 ft between trees and either 10 ft between rows or 14 ft for equipment movement.

Apricot production. Apricots and aprium varieties totaled about ten different varieties with chill ranging from a little over 200 hours to over 700 hours and no fruit thinning.

Apricot and aprium varieties include Flavor Delight, Leah Cot, Summer Delight, Katy, Chinese, Royal Rosa, Blenheim, Flavor Giant, Gold Kist among others on semi dwarfing Citation (preferred) and Myro 29C.

Peaches were on the same tree spacing as apricots and pruned to the same height.

Peaches were thinned by pruning when they were dormant during the winter. No hand thinning of individual fruit was done.

About 24 varieties of peaches and six varieties of nectarines were planted about four years ago. Again our favorite rootstock when keeping them under ten feet tall is Citation semi dwarfing rootstock.

"Red Push' Chinese Pistache for Residential Landscape

Q. We Live in the Phoenix, Arizona area and have two 10'x10' planters made of pavers and want to plant ‘Red Push’ Chinese Pistache in them. I am worried about damage to pavers from the roots. Irrigation would be from drip irrigation system on a timer.

One of the planters for a Chinese Pistache tree

A. ‘Red Push’ Chinese Pistache tree can get 50 to 60 feet tall with irrigation. In my opinion, this tree is too tall for most residential properties. You need a large landscape, a park or city streetscape to accommodate that size.

Read what Chris Martin from ASU has to say about Chinese Pistache in the Phoenix area.

The size of the planters should not be a problem when planting Chinese Pistache if using a soil coarse textured enough for good drainage and not planting shallow rooted flowers in there that require frequent, light irrigation. If planting something else in that planter, select plants that have deep roots or that don’t require frequent irrigation.

I would select a smaller tree. I have the feeling you selected that tree because of its fall color. There are other reasons for tree selection than just one trait. What sizea tree is needed for those planters? 20 feet? 30 feet? Remember, larger trees usually use more water. What shape should it be? Arching? Round? Upright?

The Phoenix area has some pretty good wholesale nurseries that grow plants for the desert including Mountain States Nursery and Arid Zone Trees. Take a look at what they have to offer.

Desert Horticulture Podcast: Thinning Fruit

Thinning fruit, or fruit removal so the remaining fruit become larger, does not have to be a mystery. It is a management process that you must do for most fruit trees. If you don't, the remaining fruit will not become larger. But on some fruit trees it doesn't work. Learn which ones it doesn't work on and why in this Desert Horticulture Podcast.

Desert Horticulture Podcast: Bottle Trees, Spider Mites and Yellow Plants in Desert Landscapes

Learn why Bottle trees are NOT desert trees, managing spider mites in home landscapes and the reasons for the yellowing of plants growing in desert soils.

Sunburn A Huge Problem in the Desert

Our light intensity is very strong in the desert. Some thin barked trees and shrubs get sunburned if they don't have enough protection from strong sunlight. The natural way to protect plants from sunburn is to allow these plants to shade their own trunks and stems with leaves. Not providing enough water can thin out the canopy of trees and shrubs and encourage sunburn.

Sunburn, like on this ash tree, starts out as a discoloration of the wood.

Plants that typically sunburn include many of our fruit trees, mostly peach and apples. Ornamental trees and shrubs also get sunburn. Plants that I see with sunburn include Japanese blueberry, locust trees, ash trees, Indian Hawthorn, and others.

Sunburn can happen to fruit, too. This yellow apple has the first sign of sunburn on the fruit facing the sun.

Severe sunburn causes the plant to die on the side exposed to the sun. Bark on this side is loosely attached to the trunk. When you pull this bark away from the trunk you may see oval-shaped holes in the wood. These are exit holes of borers. Removing the bark also removes hiding places and birds have a better chance picking them off when they emerge.

The side facing the sun dies under severe conditions and boring insects can invade the living parts on the edges of the damage. Eventually this becomes part of the tree that dies.

Having rock mulch around plants that do not like rock mulch reduces the number of leaves and increases the chance of sunburn. Plants that do not like rock mulch, like the ones I mentioned above, will develop an open canopy, leaf loss, and sunburn.

In the case of sunburned fruit the area darkens as the sunburn worsens.

What's the problem with sunburn? When humans get sunburn we recover. When plants get sunburn, particularly in a desert climate, they frequently decline and die. Attack by boring insects, or borers, is the first phase after sunburn damage. The borers create more leaf loss which increases sunburn. At this point the plant falls into a death spiral.

The side of the branch or trunk facing the sun has the most damage. In this Bottle tree it is the upper surface of the limbs.

Use surface mulch, particularly wood chips, and not bark mulch. Don't water trees and shrubs daily. Water them two or three times each week during the heat of the summer. Reduce the number of times per week during the cooler months. When they receive water, it should water the roots to a depth of at least 12 and preferably 18 inches.

Message to Landscape Maintenance Contractors and Homeowners

As I was walking my property, I was thinking about landscape maintenance contractors and what they should be doing when going from job to job. As I thought about it more, I realized it would be a good message to homeowners as well.

Alcohol wipes are safe and easy way to sanitize pruners.

Sanitize Pruning Equipment

Tree and plant diseases like Sooty Canker and Fireblight and, who knows even though its not proven, Ash Decline. We know that many plant diseases are passed along from plant to plant and residence to residence by unsanitary equipment, hands and clothing. Sanitize your pruning equipment between residences. If you see a plant or tree that you are trimming and it doesn't look right, SANITIZE any pruning equipment you use on it. Then educate your customer. Let them know you are doing it and why. Make it a difference between your company and another who doesn't know or, worse yet, doesn't care!

BTW, most tree diseases are spread when the tree is actively growing so a good time to prune is during the winter months. ALWAYS sanitize your tools when plants are growing.

Sanitize Mowers

Besides lawn diseases, lawn weeds can be passed on from property to property on unclean mowers. Everyone is using a mulching mower now but they still need to be cleaned, particularly when a disease is active. Our lawn diseases are mostly "hot weather diseases" like Summer Blight. Many of our worst weeds I hear complaints about are "winter weeds" like Poa annua. Spreading lawn diseases and weeds lasts 12 months long. Ask to use your customers hose and wash mowers between jobs, Turn the mower over and spray the blade with a sanitizer before the next job.

Handling Your Boss

More money is a good incentive. Instead of being the "tree hugger" or "plant person" on a job, use the money angle. Charge a little more for the work you do. Or tell them it will reduce costs. It costs a bit more to sanitize your tools and equipment but your customers will pay for it. As I always tell my students, "Pursue the HIGHEST dollar you can get, not the LOWEST!" Charge for your time and let the customer know you are doing something about the spread of plant diseases and weeds.

Know the Difference Between Carolina Laurel and Bay Laurel

Q. I found your blog, Xtremehorticulture of the Desert, and hoping you can tell me if my tree is a Bay Laurel or not. I looked at pictures of Carolina Cherry trees that look similar. This tree has supports which I know need to be removed at some point. The tree was planted by my builder in February of last year.

Bay Laurel just after we pruned it

A. Looks like Bay Laurel to me. Bay Laurel is a Mediterranean tree and more tolerant of our desert climate than Carolina Cherry Laurel. Carolina Cherry Laurel is native to the southeastern US and not tolerant of desert conditions without proper site selection, soil preparation and watering.

Carolina cherry laurel is native to the SE United States so it struggles when planted in hot locations with inhospitable soil. This one is suffering from iron chlorosis.

            One easy way to tell the difference is to crush the leaves and smell the herbal (Bay) aroma.  Bay Laurel leaves have a pungent aroma. When you crush the leaves of Carolina Cherry Laurel they have an aroma of maraschino cherries rather than herbal.

            The second way is to look for round “glands” at the base of the Carolina CherryLaurel leaf where the leaf is attached to the petiole (leaf stem). These “glands” are characteristic of many plants in its genus (Prunus) like plums, cherry, peach, etc.

            In 98% of the cases, the “supports” or stakes should be removed after one growing season. There are a few cases when the trees do not establish rapidly due to grower mismanagement or poor planting practices and need support longer than this.

Orange Palm Leaves Signal Time to Prune

Q. The bottom layer of my palm fronds turned an orange - yellow color almost overnight. Is this from too much water or not enough water?

Palm fronds may turn orange before they become yellow or brown and then die. Its your signal to prune.

A. Neither. The cause of these fronds turning orange or yellow is natural. These orange and yellow colors are already there, masked by the strong green color that the chlorophyll provides. We see the same color changes with “Fall color”.

Canary Island Date Palm with lower fronds dying naturally.

            The bottom layer of fronds die naturally. As these lower fronds approach death due to old age and shade, some of the minerals in the leaves are absorbed back into the palm, first turning the lower fronds orange or yellow and eventually brown. Sometimes these color changes occur quickly and other times more slowly. How fast depends on how hot it is.

Fan palm with brown lower fronds in need of pruning and removal.

            The nitrogen, phosphorus and potassium move out of the frond first followed by magnesium, chlorine, zinc and molybdenum. Lesser mobile nutrients are left behind which include sulfur, iron, boron, and copper. These mineral “remainers” dominate the content of palm fronds. This color change is your signal to cut and remove palm fronds.