Bitter Armenian Cucumbers. Why?

Q. I planted the long Armenian cucumbers and they came out so big and beautiful BUT SO BITTER all through it. Why is that?

Armenian cucumber is more closely related to melons than cucumber. You can identify it from its ribbing all down its sides. Harvest them when they are 12 to 15 in long.

A. Armenian cucumber is USUALLY less of a problem growing them in the desert than actual cucumber varieties like Straight 8 and Marketmore. But cucumbers in general can get bitter with hot temperatures and when grown on the dry side.

This is a large bag of horse bedding available from farm supply stores. You can buy small amounts from any pet store.

            Try mulching the soil (apply a thin layer on top of the soil) with something like wood shavings (horse bedding comes to mind you can get from a farm supply store) or shredded newspaper to keep the soil cooler and more moist and water more often when it gets hot. The old fruit may still be bitter but new fruit should not if it works. 

Here on this raised bed onions were mulched with animal bedding to conserve water. Just a thin layer was applied, enough to shade the soil from the sun.

             With Armenian cucumber ,if you don’t keep the soil moist while its producing fruit, they can get bitter but it is more rare than a common cucumber.

Suckers Beget Suckers

Q. All my trees send sucker shoots up around their base. I have a drip system and water three times a week for 20 minutes. What am I doing wrong and how can I stop this sucker growth?

A. It is a mixed bag. Sucker removal, and how often it’s done, depends on the plant, how old it is and how the suckers are removed.

            Trees that normally grow as shrubs tend to sucker a lot. Others don’t. When oleanders are grown as multi or single trunk trees, the suckers must be removed just about all its life. Mediterranean fan palms are in the same boat.

Cutting suckers off and leaving behind stubs just makes more suckers.

            Some plants produce a lot or suckers when young and rain this characteristic in as they get older. Most suckers, like weed control, stop sending up more if the suckers are removed as soon as they are seen instead of waiting until they get larger. Sucker removal must be done as soon as you see them rather than wait.

            How they are removed is also important. If you remove suckers when they are young you can hand pull them or rub them off with your hand or fingers. That’s easy. It’s  more work if you must get hand pruners and remove them by cutting. Not only that, but if you leave stubs behind new growth will come from those. When you leave stubs, figure three new shoots for everyone cut.

If you remove suckers while they are still young you can pull them off at the point where they grow from the tree and leave no stub behind. No stub means no sucker growth.

            There are sprays you can apply that decrease the suckering. They have names like “Sucker Punch”, “Sucker Stopper” but these sprays may be just a “band aid” for the problem, a temporary fix. Any time you use these follow the label direction to the letter.

Easy Way to Add Soil Organics with Rock Mulch Present

Q. I intend to remove the all rock layer around my roses and apply a 3 inch layer of quality compost, dig it in carefully, and cover it with western red cedar bark. However, the rock layer is convenient for blowing out all the leaves from other plants around my roses. How do I keep the rose area clean?

Roses growing in rock will start to be "unhappy" in about three to five years.

A. There is a way to make your roses happier and still leave the rock in place. I understand it was convenient before because your maintenance people would come and blow away all the debris with a power blower. With cedar bark, it will blow everywhere and make it difficult for your maintenance people to keep it clean.

Bark Mulch vs Woodchips

            First of all, bark mulch is not as effective as woodchips for a couple of reasons. Bark moves around in strong wind and when “blowers” are used in the landscape. Woodchips “lock” into place because of their rough edges and don’t move around even if the wind speed is 60 or 70 mph!  If wind is a problem I would not use bark mulch unless you are willing to “tidy up” afterwards.

Bark mulch is very attractive in landscapes but doesn't decompose quickly and blows with any type of wind.

            Secondly, bark mulch is pretty but it doesn’t improve the soil much. Woodchips disintegrate into the soil when moisture is present. In my experience, about half of it decomposes into the soil in about three years. This disintegration supplies organic matter back to the soil quickly. Woodchips don’t do that. They resist decomposition. That’s one important reason why bark comes from the outside of the tree and wood doesn’t.

Keep Your Rock Mulch

            Here’s how to keep your rock mulch and make your roses happier. Rake back the rock mulch 18 – 24 inches from your roses. Apply about ½ inch of good quality compost in this new area of bare soil and lightly incorporate it. Rake the rocks back and lightly water it in. Voilà! You have now added organic matter to the soil and made the roses happier.

High quality compost like Soil Pro has lots of benefits including better microorganism counts and loaded with plant nutrients.

            With very coarse rock mulch you can just sprinkle the compost on top of the rock and water it in. You will see improved growth from your roses in 3 to 6 months with either method. Repeat this about every two years.

 Benefits of Woodchips

What the roses benefit from is the decomposing woodchips and added organics to the soil. Rock (surface) mulch lets all the organics in the soil finish decomposing and your soil slowly becomes more mineralized. The organics in the soil start dwindling. As that happens, the roots of the roses finds itself in a progressively unhappy root environment. The unhappiness of the roots show up in the leaves with them yellowing, brown edges, and generally just not very productive.

Woodchip mulch is made from chipping the wood inside trees. Oftentimes the only way to get it is through "tree trimmers" like First Choice Tree Service.

 Don't Forget Iron

 If you still see some leaf yellowing, apply your favorite iron chelate to the soil around them once a year in late winter (late January or February in LV). If your favorite chelate doesn’t work then use the EDDHA iron chelate available from Viragrow ($20/lb) or Amazon or anyplace that sells it. 

EDDHA iron chelate is effective in whatever soil you have.

During mid to late summer or later you will have to spray it on the leaves. 
Viragrow is cheaper!

Iron chelates for leaf spraying is applied when most of the rose growth is finished for the season, like mid to late summer.

Chitalpa Leaf Drop and Leaf Browing

Q. This tree is approximately 15 years old. This house sat empty from 2004 until January 2020 when we purchased it. The house faces North and this tree receives full sun most days. Water during the 12 years was at best sporadic to none. I removed 95% of the plants and trees and just completed a comprehensive landscaping project. This tree was shaped and pruned by a licensed arborist. It suckers like crazy. It needs another round of sucker removal. I was not familiar with this specie and of course we moved in January and the tree had dropped all its leaves. The neighbors convinced me not to remove this tree because it was so beautiful in the summer, lots of flowers and beautiful leaves. I said yes because I did like the shape of it. What a mistake. The constant leaf and flower drop is terrible and a real challenge to pickup. In fact I made two mistakes, I planted another 24" box size from a local nursery . It is doing the same thing. I do not use my drip system and deep water the tree every 3 weeks during the summer months. I water from the trunk out 7 feet around the entire tree. I have a lot of large surface roots due to the lack of water. I am applying about 75-100 gallons per application. The leaves are full and supple, not dry and then boom they turn yellow, get this brown scalding and dry up and drop.

I have been researching and have not found a conclusive reason for this. The agricultural extension at NMSU wrote its not a matter of disease but rather a cultural practice. Soil may be to alkaline and getting to much water. According to Dr. Natalie Goldberg, NMSU Extension Plant Pathologists, "No plant pathogenic microorganism's were isolated from submitted samples. The symptoms occur on trees well watered as well as those that receive little water." The leaf drop starts when temperatures increase.

Can you bring me up to date with your latest information about this type of leaf drop. If I can't correct, both trees are headed for the cemetery.

A. I did print nearly everything this homeowner told me he did for this tree which was a lot. I abbreviated what he told me for the newspaper. It does not sound like a lack of water.

Older picture of Chitalpa in Las Vegas.

            Chitalpa is regarded as somewhat drought tolerant which means you should be able to water it less often than, let’s say, a purple leaf plum and still have it look good. It is not a desert species like mesquite or palo verde, but it can handle some lack of irrigation without dropping its leaves.

Limb dieback of Chitalpa from 2013.

            Unfortunately, all Chitalpa trees carry a vascular plugging disease unless propagated from seed. All the named varieties like ‘Pink Dawn’ were propagated from cuttings so they will be carrying this disease as well. You can’t see this disease outwardly but one of its symptoms can be leaf drop, starting particularly when temperatures get hotter.

            Unfortunately, Chitalpa infected with this disease is not a good thing to have around grapes or oleander either. The disease can be carried to either of these plants where it can kill several types of grapes like Thompson Seedless or it can stay hidden and spread from a bacterial reservoir that can be housed in oleander.

            The fact your tree has leaf drop in summer is suspicious. I would remove it. Replace it with a tree you like of a size in scale with your home. Single story home use a tree with mature height of around 20 ft. Two story home, look for a tree from 20 to 35 feet tall when mature. Smaller trees always use less water. Go to SNWA plant selector website to help you find one.

Bird of Paradise as a Patio Tree

Q. My HOA wants a tree in my landscape and  so I planted a Mexican Bird of Paradise last April. The main trunk broke in a windstorm so now I have three trunks almost 5 feet tall and each a double thumb-width wide, starting 8-12” above the soil. How can I make it a tree?

Red Bird of Paradise has beautiful red flowers and grows just about anywhere its warm enough. 

A. I think everything hangs on the HOA definition of a “tree”. Most people consider Mexican bird of paradise a shrub, not a tree. A good argument could be made though, that many shrubs are transformed into trees through pruning . Many of our desert trees are “shrubby”. Sometimes popular landscape shrubs are pruned into small trees and called “patio trees”.

Bird of paradise in tree form.

            The second part this dilemma is whether the HOA considers a tree to have only a single trunk or multiple trunks. In the nursery trade there are “multi-trunked trees”like crape myrtle and strawberry tree. These multiple trunks usually vary from three to about five in number. So, get ready for a battle of definitions!

Typically we think of Red Bird of Paradise as a shrub, not a tree. But if the plant is pruned and maintained as a tree, why not? I would probably chose to prune it as a multi trunk tree if possible.

            In this case, I would prune it into a single trunk, so it does not look like a shrub. Also, when multiple “suckers” arise from a single trunk, as they did in yours, they frequently have narrow crotch angles that are weak and become problems as they get older. I haven’t seen your plant but removing all but one of these suckers gets rid of this potential problem.

            Pick one sucker that is the strongest and remove the others as close to the trunk as possible. This sucker may or may not be flowering. Maybe it’s not the straightest of the suckers but it doesn’t matter. The growth of this pruned “shrub (now a tree) will straighten out in a year or two. In the meantime, other suckers may try to compete for dominance with the remaining sucker. Remove any competitors, when they reveal themselves, anytime of the year with a pruning shears or your fingers.

            Remember to sharpen and sanitize any pruning equipment you use on these plants. You are at the mercy of your HOA so be kind to the Board Members.

Is Lantana Just a Lantana?

            Lantanas are confusing but easy to grow just about anywhere, whether it’s in the tropics or the desert. They can add a variety of easy to grow colors that attract wildlife including butterflies to home landscapes. In cold climates where the ground freezes they won’t survive more than one growing season. They can be planted as annuals.

Lantanas can handle most soils and rock without many problems.

            In desert areas of the southwest they are cut back close to the ground any time after the first freeze and sucker from these small stems in the spring. A small amount of regular watering and fertilizer each year produces spectacular growth and flowers in just about any type of soil in full sun to partial shade.

Lantana can be cut back really hard in after the tops have died for the winter. 

As long as you leave one node or "joint" peeping from the rocks after pruning for the winter it will grow back.

            The three lantanas popular in the nursery trades of the desert are hybrids of Lantana camara, Lantana depressa and the trailing type, Lantana montevidensis. Collectively we call them all Lantanas. But the nurseries might call them by more common names such as ‘Gold Mound’, Purple or Yellow Trailing lantana or the multicolored ones like ‘Confetti’ Lantana by Monrovia wholesale nursery. The color and growth options are wide ranging.

Some lantana are considered "trailing" types and can grow quite large.

            Lantana is in the Verbena family (this explains their flowering) and considered tropical  (this means they frequently freeze during the winter in Las Vegas). Their flowers are arranged in clusters called “umbels” (similar to carrot flowers) and vary in color from white to yellow to red to blue and all the colors that can be made when you mix these colors together. This means plant breeding results in a proliferation of colors and growth habits for consumers. Furthermore, these individual flowers (called florets) may change in color as they age adding another dimension in variety and sales.

Some lantana flowers change color as the day goes longer.

            Some of these plants are “bushy” and others grow much longer stems and considered “trailing”. Plant leaves are considered poisonous while their flowers and fruit are not and supplement the diets of many types of birds, butterflies, and lizards. Lantana is considered invasive in wet climates and hybridizes with native Lantana found in the east but should not be a problem in desert climates unless there is free-flowing water nearby like the Colorado River or desert springs.

Lantana flowers are in umbels like carrot, onion, parsley or dill flowers.

            Lantana propagation is extremely easy by cuttings or by seed in the late spring or early fall months.

Desert Horticulture Podcast: Mineral Fertilizers

Plants don't care where their nutrients come from. But do you care about where the fertilizer you buy comes from?