Q: Do you have a recommended type or brand of asparagus that does well here in Southern Nevada? I read your blog, and you noted the purple varieties are sweeter, but do they grow as well as other types?
A: Yes, I do have recommendations on varieties of asparagus for the Las Vegas Valley climate. I grew 17 different varieties of asparagus for many years at the university research and demonstration orchard in North Las Vegas. The varieties included a few older European types, some old heritage types, varieties released from Rutgers University, University of California releases and a couple of commercial purple varieties.
All varieties grew well, but some produced higher yields, some produced longer, good quality spears for a longer time when it started getting hot. Chefs who evaluated these varieties said different varieties had slightly different flavor profiles and could be paired with different foods.
Generally speaking, University of California releases, such as UC 157, give higher yields and produce quality spears for a longer period of time when it gets hot than varieties such as Jersey Supreme and Jersey Knight, heirloom types such as Mary Washington and European varieties.
Asparagus harvest can start as early as mid-January in Las Vegas Valley, and harvesting stops about eight to 10 weeks later when new spears are smaller than pencil diameter. The remainder of the year asparagus is not harvested but grown to its full height, between 5 and 6 feet, to rebuild itself for next year’s spring production. That is when fertilizer is applied, plants are inspected for insects and diseases, and low yielding, female plants are removed.
Purple varieties, such as Purple Passion, are unique and grow well in the desert but don’t yield as well as green improved varieties such as UC 157. Purple spears are sweeter. The purple color disappears when they are cooked. In my experience, purple varieties are not as productive for the same number of years as green varieties.
Any of the green varieties can be used to produce white asparagus.
Asparagus plants are either male or female. Male asparagus plants produce more spears than female asparagus plants. Asparagus can be started from seed, not just from crowns, but the female plants should be “rogued out” or eliminated during the first couple of years if your focus is on higher yields.
I have written an asparagus production guide for Southern Nevada and will post it on my blog in the next couple of weeks.
Q: I bought Citrus Tone fertilizer for my citrus trees. What other fruit trees can I use this fertilizer on besides citrus trees? My other fruit trees are as close as 4 feet away from my dwarf orange trees. Is there a problem using this fertilizer?
A: Citrus Tone is a citrus and avocado fertilizer by Espoma. I looked at the ingredients on the label, and it seems to be a good fertilizer formulation for any fruit trees as well as roses and other important flowering shrubs and trees.
It is a mineral fertilizer and geared toward improving flower production, which results in more fruit produced. It is labeled as a citrus and avocado fertilizer, so the public knows what to use it on, but it can be used on other flowering plants as well.
The manufacturer is trying to capture uninformed consumers with this fertilizer, which is why they give it such a specific name. Informed consumers know they can use it on other plants.
The only precaution I have for you is not to apply any nitrogen-containing fertilizers to winter-tender plants after Aug. 1. This includes citrus in our location. All fruit trees should be fertilized before this date anyway.
Q: We planted a 5-gallon tree three weeks ago. At first, we watered this tree every day as the nursery directed. Then we began watering it every other day, but the leaves started falling off. Daytime temperatures are 80 to 85 degrees and drop to 40 degrees at night.
A: Leaf drop after planting falls under the general category of transplant shock. The plant was traumatized — in human terms — sometime after it was at the nursery through when it was planted.
This trauma can result from a lack of care in transporting the tree from the nursery to its new home, a radical change in locations such as growing under shade cloth and then plunged into full sun as well as rough handling during planting.
The plant went through a radical change or changes in its environment. Once adjusted to one environment, moving them to a radically different environment can cause trauma. It dropped its leaves in response. Plants can’t move. A reaction to trauma can be sudden leaf drop.
The tree is not dead but needs time to recover. Our immediate response to leaf drop is to give the plant more water. We think leaf drop is a result of drought. That would be the wrong thing to do if the problem was not from a lack of water.
When given time, traumatized trees produce new leaves and readjust to a new environment. New growth is better adjusted to the new environments. Be patient and don’t overreact.
The nursery was right to tell you to water it every day immediately after planting. Back off and water only when needed. Give the plant a one-day break between waterings. Let the water drain from around the roots. Let the roots breathe and the plant will recover on its own.
Q: Tell me when the first frost occurs in Las Vegas? I have tomato seeds that require planting indoors five to six weeks before the first frost.
A: If I give you that date, you will start tomato seeds too late. I start tomatoes from seed right around Jan. 1 in the Las Vegas climate. The first frost date in the Las Vegas Valley is considered to be March 15.
March 15 is when, historically, there is a 10 percent chance frost will occur after that date. But in most years, using this date is too late for calculating when to start seedlings.
In some years you might put out tomato seedlings, with some protection, the middle of February. Other years it might be the first week in March. Rarely will it be the middle of March.
By starting tomatoes from seed on Jan. 1 you will be ready to put tomato seedlings into protected areas outside by mid-February. If you discover this date is too early, delay putting them out for one or two weeks or until the weather gets better.
Watch weather reports for the coming week. This gives clues whether you can put tender seedlings out early in the season or if you must wait until later.
Seedlings need to be “hardened off” two weeks before putting them in the garden, particularly when starting them inside or in a greenhouse. Hardening off seedlings means moving them outside into protected locations and gradually getting them adjust to a much harsher environment. Plunge them into this harsh environment gradually.
Protect tomato new seedlings if temperatures drop into the 40s. Freezing doesn’t occur until 32 degrees, but tender plants such as tomatoes can suffer cold damage at temperatures in the 40s.
Think about what happens when you put a banana in the refrigerator. Tomato plants are also tropical, just like bananas.
Bob Morris is a horticulture expert and professor emeritus at the University of Nevada, Las Vegas. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.