San Pedro Cactus Requires Different Care Than Other Cacti

Q. I follow your column regularly in the LV RJ, but I have not seen an answer to this question: what would make my San Pedro Cactus lose its color? It is becoming pale, please see attached photo.

San Pedro cactus of the reader

A. Before I opened your picture I thought it was going to be a lot worse. This is not too bad. I have seen this cactus in much worse condition in Las Vegas.

Not all cacti are the same and cannot be treated the same. The San Pedro cactus, coming from the mountains of South America where the soils are a lot richer and there's much more water, needs different care than cacti native to the Mojave Desert.

This particular cactus will do much better if the soil is well prepared at the time of planting, much like you would prepare the soil for landscape trees and shrubs that are non-desert.

Also irrigating them is different. They have to be watered much more often than cacti native to the Mojave, Sonoran or Chihuahuan deserts.

It will also do better if protected from late afternoon sun. It likes to have lots of direct sunlight but it prefers it during the morning and early afternoon hours.

If you don't keep up with your watering with San Pedro it will begin to yellow or bleach out, scorch around the edges, bleach out and die back. This means the soil that you're using must drain extremely well or you will kill it by not having adequate drainage.

Consider moving it, replanting it with the soil that is Sandy and gravelly and amended with compost. Make sure the area has deep soils that drains easily. Give it is much sun as possible but try to avoid direct sunlight after 2 PM. Water it frequently when temperatures are above 100° F.

Radishes Should Be Planted When Temperatures Begin to Cool

Q. I planted radish seeds in 8" deep planters using miracle grow potting soil . After approx. 10 days they grew up to approx. 3" developing 2 leaves and started falling over. They do not mature. The type of radish seed is Cherry Belle from Ferry Morse.  I've planted two different times and get the same results. What am I doing wrong?

A. It is usually considered too hot right now, with daytime temperatures still hundred degrees F, to plant radishes. They do much better when the temperatures begin to cool.

I would start planting them no earlier than about mid-October and you should be able to plant them throughout the winter in successive plantings up until about May when it gets too hot. Cherry Belle is an excellent radish and will do well here. Here are just a few of the many varieties we have grown in Las Vegas.

Chinese red meat radish

Radishes growing with irrigation from drip tape and straw mulch applied

French breakfast radish

White icicle radish

I have tried dozens of different radish varieties and not found a radish yet that does not like our climate. However radishes grown during the cooler months are not as spicy but sweeter than those grown in the hotter months.

Hold off for another month and try replanting the seed. The potting soil may also be a problem. Seeds like firm seed beds, not soft seed beds. I would take your soil amendments and mix it with existing native soil or good-quality sand and tried again.

After you work in your compost and prepare the area for planting, your shoes should not sink into the soil more than about 1/2 inch for a good seed bed. Radishes also grow well in containers.

Containers do not have to be terribly deep. 12 inch deep containers are adequate for radishes and allow the soil to drain and not become a problem for the plants.

So remember to use a soil mixture with compost or other soil amendment and make sure the seed that the seed bed is firm and not soft and fluffy. Watering twice a day until you see the seeds germinate should be enough. After they germinate water only once a day. I hope this helps.

Keep Beneficial Insects Thriving by Careful Use of Sprays

Q. I'm wondering if you can recommend any easy plants that are big-time lures for beneficial insects here in Las Vegas.  In northern CA, where I spend the rest of my time, my Ammi majus aka False Queen Anne's Lace reseeded just about everywhere.  While it made for a very messy looking plot, while in bloom, the good bugs were swarming my garden for months!  Since I won't be around as much in Vegas, I'm looking for a tamer perennial solution here.

A. Build it and they will come.

Beneficial insects are lured by a food supply. If you don't have a food supply for them they will leave. If you have a diverse plant palette in your garden you will attract many more beneficials and they will have a better chance of keeping bad boys in check.

Building up a beneficial insect population is really more about smart use of appropriate pesticides. Use organic or natural pest control products that don't have a long residual and use them only if you see a potential problem arising.

I see lots of ladybird beetles and green lace wings come into an area that have the pests. When I see a lot of spraying with conventional insecticides, these populations are usually low to nonexistent.

Green lace wing adult

When a person is selling organic fruit or vegetables one of the things I look for on the products is the presence of green lace wing eggs. If the products have not been washed you can usually see them if you know what to look for.

Lacewing egg on peach

 lacewing egg on peach

Ladybird beetle on peach

I will post some pictures on my blog for everyone to see. Others may have plants that are their favorites for doing this. Hopefully they will post their comments.

Why No Fruit on Kumquat?

Q. Just this last year we have had very little fruit on our Kumquat whereas prior to that the tree was ample with fruit. The tree appears to be healthy, just no fruit. The only difference I can think of is that in previous years I covered the tree whenever the temperature was below freezing. However, this past year I only covered it when the temperature fell to the upper 20’s. 

A. Kumquat is a very winter hardy citrus and can survive most winter temperatures here without any problems provided it is in a sheltered spot. It is considered one of the most cold tolerant of the citrus. The key question you have to ask yourself is whether it produced any flowers or not this past year. No flowers equals no fruit.

The major reasons for early fruit drop are temperature and irrigation problems. If we have freezing temperatures or if the plants become water stressed from not enough water, they tend to drop fruit and flowers if they were produced. Flower buds and fruits are much less hardy to freezing temperatures than the plant itself.

Kumquat may produce fruit all through the year but tend to produce fruit in the spring and fall months and through the winter. If it does get some winter damage, you would have seen plant dieback.

When dieback occurs, the plant will regrow to the height it was before it had damage and produce very few flowers. Once it reestablishes its previous size it will then begin to flower again and produce fruit.

If there were some spring freezes the flower buds would be killed before anything else would show any damage. This would tend to minimize fruit production. If the plant receives a lot of fertilizer, particularly nitrogen, it may tend to put on new growth with few flowers and of course very little, if any, fruit.

Buckets Can Be Used for Drip Irrigation

Q. My pine trees are over 20 years old and very tall.  I looked on the net and found a YouTube video out of Kansas showing the man using a 5 gallon bucket with a pin hole in the bottom for the purpose of watering them. I called out my landscaping guy and he said that I am wasting water by watering that way. He said to dig a trench and fill it with water so it can be soaked into the ground and reach the roots of the tree. I do not have the ability to dig trenches.  Am I doing right by watering with the buckets or is he correct about his method?

A. Using a bucket with a small hole in it works just like drip irrigation. I would use about five or more buckets and distribute them under the canopy, about three or 4 feet apart, if you don’t mind looking at them.

Using buckets is the easiest and similar to the very first form of drip irrigation which was sinking unglazed ceramic pots into the soil. Make the holes small. Should run out in about one hour or so. The water will not run off and accomplish the same thing as a drip system but with more work on your part and kind of ugly. But it will work.

Make sure the water leaks from the bucket in the 12 inches depth of soil beneath the tree. If it runs into the soil below this 12 inch depth it is possible it may miss the roots that actively take up water. In our urban landscapes these roots are typically close to the soil surface. Roots for anchoring the plant usually run deeper than this and are not as responsible for water and nutrient uptake as the surface roots.

There is another form of using buckets for irrigation. This concept was pioneered by a hero of mine of the name Dick Chapin who passed away a couple of years ago. He is the father of American drip irrigation and developed the first drip tapes that were used in the greenhouse and nursery industry starting back in the 1960s.

Regardless of your religious beliefs, what he was able to accomplish in the distribution of low-cost, drip irrigation systems using buckets (aka bucket irrigation) was truly remarkable. This is what made him a hero of mine. You can learn more about his foundation below. 

I have implemented the strategy in my international work and it will also work here if you have a small garden area. If you want some classes on how to construct these or information posted on my blog showing you how to do it, just let me know.

Dick Chapin's living water foundation

Sometimes Amaryllis Can Get Big

Q. What do I do with my 4 foot high amaryllis plants?  How much should I cut them back? 

A. That is a large one from your description. The size of this plant may vary with a variety and light exposure. If they are not getting enough light the leaves will be very succulent and long. With adequate light believes should be leathery, stouter and more durable.

You have your amaryllis in good exposure it sounds like with it in the East side with some filtered light during part of the day. Amaryllis does well with half-day sunlight in the mornings. As you've already expressed I'm sure that you amended your soil with compost the time of planting and mulched the bulbs.

Sometimes the flowers need staking because they can get a little top-heavy. They will die back at the first frost. At this time feel free to cut them back to the ground. Cover the bulbs with 4 to 6 inches of wood mulch through the coldest part of the winter.

When all danger of frost has passed go ahead and uncover them and let them warm up. I would fertilize lightly once a month.

On a side note the term Amaryllis in English includes plants that are not truly Amaryllis. The one we see in stores most of the time is Hippeastrum but the trade has called it Amaryllis for so long the name has stuck and it's easier to pronounce. One comes from South America and the other comes from South Africa. One is a little more cold sensitive than the other.Both of them produce gorgeous flowers.

Black Spots on Peach Leaves May Be from Lack of Light

Q. Can you tell me what this is on one of our peach trees? The leaves are developing black spots on the margins.

A. I am looking at your picture now of the peach leaf. It was hard to see what the problem might be with only one picture and that picture was low resolution.

What I saw was one leaf inside the canopy in some shade with some black spots developing on the leaf margins. I couldn't be certain but it looked like there was a yellow halo around the black spots on the margins. I don't know if this is typical of all the leaves or just the leaves in the shade.

For me there were two possibilities; irrigation or a disease called shot hole fungus or Coryneum Blight. If it was over the entire canopy and it involves leaves in full sunlight then I would tend to think it was irrigation related.

It usually occurs if the tree is not getting enough water at the time of an irrigation or if you waited too long between irrigations. If the tree has gotten considerably larger in the last two years than I would add any emitter or two to the irrigation of the tree.

I would also mulch the surface of the soil to conserve water and reduce water stress.

If this is Coryneum Blight then you would spray the tree with a copper-based fungicide such as Bordeaux mixture immediately when the leaves fall from the tree this early winter. You would follow up with the spray in the spring as the leaves are coming out and new growth is emerging but after blooming has finished.

Blog to Follow on Desert Gardening for Quality Food

Take a look at what you can grow in the desert!
Some of you trying to grow food under desert conditions will appreciate this blog by April Asher documenting her trials and successes in desert gardening.

Click on this link to follow April

Texas Sage and Sage Herb Allergies

Q. Is the Texas Ranger shrub in the Sage family? This question is prompted by allergies to the Sage family of plants.

A. No, Texas Ranger or Texas Sage is not part of the Sage family. Texas Ranger is also known as Leucophyllum fretescens.

The following is from Wikipedia and it is a breakdown of its taxonomy. It is in the same Order, but not the same Family. I would guess that they do not have a close enough association to cause the same types of allergies but this is not a guarantee.

Taxonomies are a human invention and plants may or may not follow these classifications regarding their physiology.

This is a breakdown of the taxonomy of Texas Sage or Texas Ranger.

Kingdom:        Plantae

(unranked):     Angiosperms

(unranked):     Eudicots

(unranked):     Asterids

Order:             Lamiales

Family:           Scrophulariaceae

Genus:             Leucophyllum

Species:          L. frutescens

Texas Sage on Wikipedia

This is the herb called Sage known as Salvia officinalis. This is also from Wikipedia and a breakdown of its taxonomy.

Kingdom:        Plantae

(unranked):     Angiosperms

(unranked):     Eudicots

(unranked):     Asterids

Order:             Lamiales

Family:           Lamiaceae

Genus:             Salvia

Species:          S. officinalis

The herb Sage on Wikipedia