Decrease in plant size decreases need for water

Using fewer plants makes the remaining plants more visually important and saves water.

A landscape full of plants is enamoring. It’s a jungle of plants. The temptation in our Western Hemisphere is to fill voids with plants. Western floral arrangements are full of plants.

However, each plant uses water. If we cluster them together, they are easier to water, easier to manage and collectively use less. However, the more area not covered by plants, the lower a landscape’s water bill.

Use smaller plants. Smaller plants do the same job as larger plants and use less water.

If you already have large trees and shrubs, prune them smaller. Making plants smaller decreases their need for water. Remember, decreasing plant numbers and size only works if the amount of water they are given is also decreased. Manage the water they get.

Use xeric plants. Xeric plants are watered less often but with the same amount of water. Plants watered less often still look good but leads to a decrease in total landscape water use during the year. To do that, these plants need to be on a separate valve or station. Place xeric plants on separate valves or water lines (hydrozone) from plants that need water more often.

Once landscapes are designed and installed, future landscape water use, and how often they need water, is carved in stone. Watering plants less often does not always lead to better-looking landscapes. Some plants, like mesic plants, need water more often. Plants demand for water is not negotiable.

When plants are watered less, changes in appearance occur: growth slows, leaves or needles begin to scorch and the canopy thins, leaves or needles drop, branches die and finally the plant or tree may die. Use this as a signal to water more often. But water deep. When water is returned, many plants spring back to life.

There is a trade-off in perceived beauty versus water use. Landscapes do not just have to be for plants. Conserving water is a reason homeowners are encouraged to use art forms in their landscapes that do not need water.

Homeowners can become familiar with creating beautiful negative spaces without the use of plants. Our job in the desert is to create landscapes that conserve water while enjoying it at the same time.

Q: I have an apricot tree and the leaves have been a lighter green the past couple of months. Are the leaves lacking nutrients?

A: Perhaps. Look at this year’s growth in several places as well as its leaf color. New growth should average about 18 inches for productive trees. Leaf color should be dark green. If leaf color is a light green and new growth is well under 18 inches, then consider applying a fertilizer or rich compost.

Fruit tree fertilizer is applied in the early spring, usually once a year. Unless the soil is very sandy, once-a-year application of a fruit tree fertilizer is usually often enough. Use the rate on the fertilizer bag as the maximum rate to apply. If applying twice a year, divide the rate on the bag in half.

Soil improvement may be needed also. Use rich compost instead of fertilizer. Never apply a fertilizer or rich compost closer than 12 to 18 inches from the trunk. Both fertilizers and rich compost can damage plants if it is applied too close.

To be on the safe side, water the soil immediately after applying fertilizer. Water dilutes fertilizer and rich compost. Never apply compost or fertilizer near a plant’s trunk or main stem.

When applying a rich compost, rake rock or bark mulch away 3 feet from the trunk in all directions. Apply a thin layer (one-quarter inch) of rich compost, water it in and re-rake the surface mulch back into place. Do this once every year. If it is a nutrient issue from a lack of fertilizer, you will see a change in the leaf color in about two weeks. This color change will last months.

Light green leaves also can be from either drought or daily watering. First, correct daily irrigations during the summer. That’s a big no-no except for lawns, flower beds and areas for growing vegetables. Big trees and shrubs can’t handle that.

When watering, apply water deeply to tall plants. If it calls for more continuous watering, increase the size of the irrigated area under the tree. Apply water to at least half the area under a plant.

If the leaf color is light green, it may be a sign the tree is watered too often. Give the roots at least one day between irrigations during the summer otherwise, the roots may drown. This allows the soil to drain water and the roots to breathe.

Q: I have seven robust pineapple plants, two of which are very large. I plan to move them to my small greenhouse over the winter. One plant now has three pups, and a large plant only has one pup. What would be the ideal management of the pups? Leave alone or cut down?

A: When we grow pineapples for fresh eating at our farm in the Philippines, we use the tops from discarded pineapples. Commercial growers use side shoots or “pups” from known varieties. Using the tops takes a few months longer than using the pups or side shoots but is more economical.

Pineapples barely survive freezing temperatures. They are tropical.

The production time for pineapples grown in Las Vegas is closer to two years. Part of its time growing must be in a greenhouse or at least a protected area. Greenhouse-grown pineapples produce fruit in less time than without a greenhouse.

Heated greenhouses are like the tropics. Unheated greenhouses extend the time for planting because of the protection they provide. Use a soil thermometer for planting in unheated greenhouses.

Even though planting without a greenhouse can be as late as mid-March, you can start looking at favorable air temperatures for planting outside after mid-February. Start planting pineapple outside after the last possible frost and plant them in an area with very bright indirect or morning sunlight. East sides are better than west or south sides. Total time from start to finish is 16 to 24 months after planting depending on the variety you choose, weather and soil type.

Pineapples need warm, moist, mounded soil. Before planting them outside, mound and cover a 3-by-3 area for one week with clear plastic to warm it. Plant cut tops or side shoots (pups) that have had a chance to heal for a few hours. Experienced gardeners plant tops or sides shoots from a variety they like.

Space them in rows about 2 feet apart. They can be closer but crowding and poorly drained soil can be a problem. Water them with drip tape or tubing. Tops will produce fruit in the longest time while 4-inch-long pups or side shoots produce fruit a couple months faster.

After about 10 to 15 months of growth, they should initiate flowering. If first planted in February or early March, the plant should be old enough to start flowering by the following summer. Fruiting takes about four to five months after that.

Q: I know of two HOAs that do not permit wood chips near the residences due to bark scorpions. What do you tell people?

A: Caulk openings in the foundation of your home wider than a credit card. If you choose to use pesticides, apply them to exterior walls around the foundation of the house from the ground up to 1 foot. Make applications around doors, window eaves and other potential points of entry.

This is called a barrier spray and is applied at least once in the spring and once in the fall when temperatures begin changing. Temperature changes are the usual time bark scorpions follow their prey inside houses.

Young scorpions are very susceptible to the same pesticides used for controlling spiders. Older bark scorpions are more difficult. Apply a barrier spray any time a load of wood chips is delivered and spread. They last only about one or two weeks depending on the weather.

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.