Q. What can I do to correct all the issues that damaged star jasmine this winter?
A. Hard to say exactly what problems you were having, but generally I would call them collectively stress-related. The stress could have come from freezing temperatures, lack of water, high salts, poor soils or lack of soil amendments such as organic matter.
The plant is from eastern and southern China, which means it is not from a desert and not really a desert plant. We must adjust its environment as much as we can for that reason. It is not going to like desert soils or rock mulches.
Soils for growing star jasmine must have lots of rich soil amendments; the plant will really appreciate wood mulches. This plant does well as a groundcover but I think it is best as a north- or east-facing trellised vine, particularly near a window or door that can be opened in the spring.
The flowers are very fragrant so it should be planted where the fragrance can be appreciated. It is an old-fashioned plant. Southerners might know it as “Confederate jasmine.”
It handles the cold winters well if it is healthy and not in rock mulch. At really low temperatures the leaves may get that bronzy, yellowish color characteristic of winter damage, but it will handle temperatures to 10 degrees Fahrenheit pretty easily. Citrus leaves will bronze in winter the same way because of cold.
Flood the soil with water a couple of times to remove possible salts and let it drain. Add compost to the soil surface around the plant and water it in. Replace rock mulch with wood mulch but keep the mulch away from the stems to prevent collar rot.
Fertilize in the spring with a good quality fertilizer for flowering plants like roses. Shear off the old growth and let it regrow in good health.
Q. I have used Italian cypress in moderate climates with very good success, but now I will be moving to the desert in Pahrump on one acre and want to put in about 30 to 50 of these for a windbreak. Is there anything special I need to consider when planting these in a desert climate?
A. Pahrump gets colder than Las Vegas and will dip down to 10 degrees Fahrenheit frequently. Italian cypress is fine there, but Pahrump has trouble growing some plants that will grow in Las Vegas’ warmer winter climate.
People in Pahrump love to plant windbreaks along the edge of their large properties. But, in my opinion, if windbreaks aren’t planted in the right locations and not the correct distances from the areas to be protected, you are just wasting your time, money and water.
Watering them on drip irrigation will work. Be sure you size your drip irrigation mainline, submains and laterals large enough to handle the irrigation you will expect to provide them in the next 20 years. These plants will require more water as they grow.
Drip irrigation requires maintenance. This includes flushing lines regularly and using appropriate filtration or you will have nothing but problems. You can inject fertilizers into drip lines but you must have good filtration.
I usually recommend about a 50-50 addition of soil amendment, preferably compost, to raw desert soil at the time of planting. Our desert soils are extremely low in organic material.
They will also perform better and have fewer problems if you can surround these plants with several inches of wood mulch. Keep the mulch away from the trunks about 12 inches for the first five years.
Rabbits don’t like Italian cypress, but if they are hungry enough and the population explodes due to recent fires, your plants will be damaged or destroyed by rabbits. So protect them.
I want to gently remind you that we do live in the desert. And although there may be only the cost of pumping the water in your mind there are other “costs,” too.
We need to find a fine balance between our quality of life and respect for where we live.
Q. I have oxalis as a weed. How can I control it? I am ready to use chemicals after trying to rid it by digging and pulling with no success. Having it in my grass is bad enough but now that it is in my iris beds I want to kill the dang stuff!
A. Oxalis is very difficult to kill. You cannot remove it by pulling or digging. They usually come in with nursery plants where the new owners think the oxalis is a cute little clover that will bring them luck.
This is a nasty pest. Sorry I could not post the picture here but you can see it on my blog. The usual control method is herbicides. In lawns, it will require a lawn weed control application in the spring containing dicamba or triclopyr and then again in the fall if you still see it.
One application won’t suffice. It will usually require another one after it comes up again after it first seems to die. There are little bulbils underground that act as “seeds” and renew the weed, so repeat applications are required.
In nonlawn areas, I have heard that glyphosate or Roundup will control it with one application in the spring and another one next spring when you see it.
You may need repeat applications, but one of the keys is to try to kill it when it is “happy” and is ready to grow and multiply. This is usually spring and fall.
Go to your favorite nursery or garden center (you may have to look at several such as Lowe’s, Home Depot, Star Nursery and Plant World). Go to their weed killer section. Look at the active ingredients.
On another note there have been some reports that chickens love the little bulbils underground and will scratch and pick at them with relish. So if you can tolerate chickens and the damage they can do to a garden, you have another option.
Bob Morris is a horticulture expert living in Las Vegas and professor emeritus for the University of Nevada. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.