Wetlands a unique, crucial part of Springs Preserve

When coming to the Las Vegas Springs Preserve, 333 S. Valley View Blvd., you’ll take a walk through a deep ravine. You’ll hear water falling over rocks at your feet as a creek meanders through the ravine. But don’t get the idea you can drink the water. You will see signs telling you not to, because it is reclaimed water.

The water flowing through that ravine comes from the wetlands in the preserve’s gardens. The wetlands is a unique feature in the gardens and often overlooked by visitors. It is in the center with paths around it, and visitors become fascinated with other features. Your first glance at the cattails and reeds may cause you to pass it off as a swamp, but it really contributes to the overall mission of the preserve.

It is like many other wetlands found naturally in desert settings across the Southwest. Within that area is a thriving community of many plants, microbes and insects. Like the natural springs that once flourished on the Springs Preserve, the wetlands also flourished and water pushed out from the meadows, which is where Las Vegas got its name.

As you travel across the Mojave Desert, you will find many wetlands with a year-round water supply to help native and migrating wildlife survive. Warm Springs in upper Moapa Valley, 60 miles east of Las Vegas, is a classic example of wetlands. It still has water flowing from the ground, providing high-quality water for animals and wildlife as well as a source of water for Moapa Valley farms and residents. If you go to Warm Springs, you’ll see acres and acres of palms along with the endangered Moapa dace fish. The springs used to be a beautiful resort oasis.

These popular wet spots are busy communities of plants, fish, amphibians and insects, and animals remain all year while hundreds of bird species pass through each year. Native trees and bushes cluster around these wetlands, offering homes and shade for them.

With this in mind, the Springs Preserve placed the wetlands in the center of the gardens. All the water that passes through the preserve ends up in this wetlands, where it is recycled and used at the complex. The pollutants in the water provide lunch for many critters that live there. Here is how it’s done:

Hidden below the cattails and marsh you’ll find gravel. As used water enters the wetland area, it flows through the gravel to filter out the larger particles. Tiny helpful microbes and plant roots grow in the air pockets between the gravel and the particles become their source of food. At the same time, these tiny creatures clean the water by consuming pollutants such as nitrogen, phosphorus, organics, and break the particles down. To them, it is frosting on the cake. Mmmm, delicious!

The roots of the cattails and other plants act as a living filter. They trap the solids and absorb nutrients from the water, which becomes a natural fertilizer. The plants then generate and send oxygen into the area around their roots to encourage more microbial grow.

To make sure the pollutants are removed, water spills into another pond. The water then goes back into the system to irrigate plants, flush toilets and provide water for the creek.

Now for the rest of the surprise: lush grassy meadows circle the wetlands. Water soaks from the wetlands to create the meadows. Spread through these meadows are native desert willow trees, which you find in washes across the desert. Further away are towering mesquites that came from the Desert Demonstration Gardens. And under these trees are many native plants. The meadows really put a crowning touch on the wetlands.

When you come to the gardens, take some time to really focus in on the wetlands.

Here are some questions I encountered this week:

Q: What are the majestic metallic green insects that are feeding on my plums?

A: They are June beetles. I know they are mammoth but give them a break, they are only cleaning up fruit damaged by birds. If they still bother you, build a trap to catch them. Take a foot-square piece of door screen and make into a funnel with an inch opening at the base. Place a piece of melon inside the funnel in a wide-mouthed jar. The smell from the fruit attracts them. Once in the jar, they can’t get out. At this point, destroy them.

Q: Our homeowners association landscape had many Indian hawthorne bushes out in the open with fried leaves. Our landscaper said they were not adapted to open hostile conditions and suggested yellow lantanas because they are such prolific bloomers. We changed over and now the lantanas are not blooming. Why?

A: When lantanas stop blooming, they are not getting enough water. Give them a good soaking.

Q: What are the bugs eating the leaves on my Texas mountain laurel and how do I control them?

A: They are pyralid moths. They won’t threaten the plant and are easy to control. Apply Bacillus thuringiensis or Bt, a biological control agent sold as Dipel or Thuricide.

This is one plant you don’t prune until after bloom. If you do, you are removing its flowering buds for 2008. Don’t even consider shearing the mountain laurel. Too much pruning and heavy fertilization creates too much shade and limits blooms. Full sun is essential for good blooming.

Q: Can we grow star pine in Las Vegas?

A: Star pine also is known as Northfork Island pine. It often is sold as a houseplant, but when temperatures dip into the teens and our heat and wind works on them, they do poorly. It is a tree in climates such as Panama. It is sold during the Christmas season because of its symmetrical shape.

Q: A contractor planted some shrubs and installed a drip system for me. All the shrubs did great, but why did two plants die? When I dug them up, the root balls were bone dry.

A: I strongly suspect your plants are not getting any water. Check to see where the water is dripping from the spigot. It is most likely running away from the root ball. Either move the plant under the spigot or extend the tubing to the plant so the water runs directly into the root ball.

Q: Are the fruits on my flowering plum poisonous?

A: No, but they are tart because the plant is bred for beauty, not to produce fruit.

Q: Where did the leaves on my evening primrose go and why are the flowers so puny?

A: There is a small caterpillar stripping off the leaves so the plant can’t manufacture food to keep them blooming. Control the pest with Dipel or Thuricide.

Linn Mills writes a garden column each Thursday. You can reach him at lmills@reviewjournal.com or at the Gardens at the Springs Preserve, 822-8325.