Master gardeners offer tours of Extension Botanic Gardens

Join the master gardener docents starting Saturday, Nov. 12, for guided tours of the beautiful and interesting Extension gardens (corner of Paradise Road and Windmill Lane) as well as the interior courtyard. There are a variety of plants to look and learn about.

Learn which plants performed the best and why. Learn which plants use the least amount of water and, finally, where you can get them. Dates vary to make it convenient for you.

Tours are conducted two or three times a month until April. Register in advance on Eventbrite by typing in Garden Tour in the search bar. Future tours start midmorning and oftentimes last 90 minutes.

The Extension Botanic Gardens feature more than 1,500 species of plants, including many found nowhere else in the Las Vegas Valley. Docents lead attendees through highlights of the gardens and answer tough questions about these plants and where you can get them.

Tours are fun, informal and full of exercise. Wear comfortable walking shoes.

Q: What are your top plant recommendations for a desert xeriscape landscape?

A: There are many plants that fit the bill. I can make plant recommendations, but the problem you may have is finding them at local nurseries.

When selecting plants to lower your landscape water use, use as few plants as possible and focus on plants in scale with the landscape and home. In other words, don’t select a 50-foot tree to do a 20-foot job. Big trees use more water than smaller trees.

All plants use water. Whenever a tree is planted you make a commitment that it will be watered and healthy. It can be difficult to judge plant water use, but generally, trees from deserts are capable of using less water than those that come from wetter regions.

Knowing where the tree originates tells the buyer a lot. I’m surprised plant origin is not used more often when selecting plants.

I categorize plants as either “mesic” or “xeric” in their water use. Different xeric trees run the gamut from using little water to demanding more water.

As an example, look at the difference in water use between a foothills palo verde (found on desert flatlands) versus blue palo verde (found in desert washes). Both are classified as xeric trees and use less water than an ash tree or even Chinese pistache.

When looking for plants for the Las Vegas area, focus on plants that withstand winter low temperatures of at least 20 degrees. Use these as backbone trees for your landscape that cannot be lost due to surprising winter cold temperatures.

These are usually trees and large shrubs used to provide shade for the home and outside sitting areas. If you can afford their water use, select plants that handle winter temperatures warmer than this for your enjoyment and experimentation.

Q: Any suggestions for plants that like to live here, low in maintenance, have no thorns and smell good?

A: Many plants that have all these features are smaller in size. Sages, in general, are good choices for desert landscapes. They supply seasonal color, smell good and have few thorns.

But be careful when choosing any old sage. Make sure your pick ranges into our deserts if it doesn’t originate here. Most sages categorized as salvias can be used for smudging.

Another category of plants to consider is the desert penstemons. Not any old penstemons, but desert penstemons (make sure the penstemons you select range into our deserts) such as Firecracker, Parry’s and Palmer’s penstemon.

Penstemons as a group have a huge range and can vary from Canadian-type dry conditions to our hot deserts. All tolerate dryness, but not all of them have the same tolerance for desert heat and sun.

Desert verbenas are another good choice, such as varieties Gooding, moss and sandpaper. Although the group called verbenas is not as big as the penstemon group of plants, it is large and rangy, and care should be used when selecting a verbena for a desert landscape.

Q: What plants should I use to lower my water use?

A: You can have the most water-efficient landscape in Las Vegas, but if it is watered more often than needed then water is wasted. The plant getting water-stressed the most dictates the amount of water applied.

Poor irrigation scheduling wastes water. This is the reason I like to tell people: “People use water, plants don’t.”

Secondly, I looked at a recommended plant list recently, and few of the listed plants were available. What height is needed to do the job? Should the plant be deciduous or evergreen?

Know your starting point. Decide how much water is applied to your landscape.

This is easy to do if you realize anywhere from 60 percent to 70 percent of your water bill is used for watering landscapes. Take the gallons of water reported in July, divide it in half and put that number into your total landscape area.

If you water less than 15,000 gallons for every 1,000 square feet of landscape area, you are doing a pretty good job. Thirty-thousand gallons is not bad, but 45,000 gallons and greater needs improvement.

Q: These are my first pomegranates. My pomegranate plant is a Utah Sweet variety and is approximately 2 years old. The large fruit split, and the seeds were not red but tasty. What can I do to improve next year’s crop? Can you give me some hints for fertilizer and watering that I can add?

A: I think your harvesting of the fruit is too late. Utah Sweet pomegranates are usually ready to harvest sometime in September depending on the weather. Pomegranates collectively are ready to harvest between September and November, but the exact timing depends on the variety.

The other observation I have is that the variety called Utah Sweet is not 100 percent red. It has red, pink and white in the arils (soft flesh plus the seed which may be soft or hard depending on the variety) and rind.

The seed is considered soft or edible. The fruit is noticeably sweeter because it does not have the tannins which can make the juice taste bitter to some people.

One of the latest varieties to harvest is called Wonderful, which is ready to harvest and the sweetest around Halloween. The Wonderful variety, besides being fully red when ripe inside and out, is what some people would consider bitter tasting because of its tannin content in the arils.

Fertilize all fruit trees including pomegranate once in February or March as new growth appears. Water them like other shrubs in the yard. They perform best when surrounded by wood chips and planted with compost.

Q: Can you tell me how high to prune back my rose bushes this next spring? Also, is it possible to transplant an older rose bush?

A: Roses or rose bushes come in lots of different sizes, varying from about 2½ feet tall to 6 feet tall or more. If you’ve just got a few of them, then you deadhead them (cut off spent flowers) when they finish blooming and prune them back in January. How far to prune them back depends on the variety and the type of rose.

I would never prune them lower than about 18 inches from the ground because they may sucker from their rootstock, which is undesirable. But some of the varieties are tall and should be pruned taller during the winter. Most will be pruned in the 18- to 24-inch range. I wish I could be more specific; send me some pictures of your roses and I will be more precise.

Regarding moving your rose bushes or finding a new location, it is best if they are moved in early spring or fall but before they are three seasons in the ground. When moving them, put them in the cooler east or north sides of walls or buildings but don’t plant them near hot walls.

If you must plant near hot walls, then plant them in a location several feet away from hotter west or south-facing walls. When moving plants, the top should be cut back one quarter to one third of its height.

Roses don’t like to be in rock landscapes. They perform better in landscapes covered with 2 to 3 inches of wood chips or with stuff that easily rots and enriches the soil.

Bob Morris is a horticulture expert and professor emeritus of the University of Nevada, Las Vegas. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.