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.