Can Your Desert Trees And Plants Fight Climate Change?
Research is coming out about the importance of planting trees to combat climate change. Trees absorb and store carbon dioxide.
There’s debate about how much trees will help. But in the desert, what kind of trees do you plant anyhow? Climate change will also tax water supplies in the desert, so you want trees that don’t take a lot of water.
Norm Schilling, host of KNPR's "Desert Bloom" and a commercial horticulturist in Las Vegas, answered questions about gardening in Southern Nevada.
Schilling brought in a piece of bark from a pine tree because he is growing more concerned about a small burrowing insect called the Mediterranean pine engraver.
The tiny insect carves up a tree but it also brings with it a fungus called the blue stain fungus. The fungus can kill a tree in very rapid order.
"The decline is really, really rapid and there is no known cure or no cure that I know of," Schilling said, "The key is to keep the pines healthy that really seems to reduce the incidents of it."
He said it isn't a widespread infestation but he wants people to be aware of it. Most pine trees in Southern Nevada are either Aleppo pines or Mondell pines, which are from the Middle East and they thrive here.
If a pine tree becomes infected, Schilling recommends having it removed right away and then putting it through a wood chipper at the smallest possible chip setting to eliminate the insect before it can move to other trees in the neighborhood.
Best trees to plant to address climate change:
Schilling: Of the 15 to 20 trees that have the highest carbon dioxide absorption only two will do okay in Southern Nevada. Those are the Virginia live Oak and the red oak, which can be a little temperamental here but its a beautiful tree.
Oaks are good trees because they last a long time. Trees that live a long time will perform more carbon sequestration. However, all trees are going to take carbon out of the atmosphere and you want trees with a long lifespan so you want trees that are well suited for life in Southern Nevada.
The Palo Verdes and acacias and mesquites are all in the pea family basically. They do nitrogen sequestration. They pull nitrogen out of the air, which means you need to fertilize them less and fertilization can also add a lot of carbon.
Basically, plant desert trees, don't overwater them... because you want that tree to be part of your home and your life for decades.
Norm's Favorite Desert Trees from Desert Bloom
I keep banging on this drum. We live in the desert - plant desert trees. You're going to have less frustration. You're going to use less water. You're going to have a happier healthier tree.
A caller asked if there was another ground cover, like clover, that could be used instead of grass.
Schilling: Turf became popular because it grows well and can take foot traffic. I haven't found a ground cover that is a good substitute because most - like clover - don't take foot traffic.
I have a half-acre. It had a big lawn in the back. It was beautiful. I took good care of it and I took it out and here's why: I did want to make a difference for the environment. I wanted to save water... but the main reason I took it out is because a garden of mixed perennials and succulents, flowering plants... trees bringing in shade, there is just a beautiful garden feel that you can create. And you can create that using desert plants.
Elizabeth wanted to know if oleanders would be a good tree to plant along a wall for more privacy:
Schilling: They are a tough plant that do well here. I would avoid the white variety but pink and red will not grow as big.
Fall is a great time to plant them. When you do plan, use younger and smaller plants because they cost less and use less labor. The smaller trees and shrubs establish quicker. It is poisonous so don't let pets or children eat it.
Other plants that would work for as a privacy screen are Arizona rosewood, Texas mountain laurel or shiny xylosma
Texas mountain laurel
Stephanie wants to know if the root system of a tree can be trained to stay clear of a house or garden wall:
Schilling: Too big of a tree too big to a target, you're asking for trouble... ultimately, if its close to the wall and one little root when it's young gets under the footing of the wall and then that root swells and then five, 10, 15 years later - you never know - you start seeing the wall crack.
So, the best thing to do is give them distance. Ten feet at least for a pretty good-sized species, 15 feet, 20 feet, if you have a large enough yard. If you don't, plant a tree that is going to reach a mature canopy spread of maybe 15, or 20, or 25 feet. Some day it will give you all that shade in your small backyard that you want.
Steve is concerned about his palo verde. The trunk is turning brown:
Schilling: The trunk turning brown is part of the natural formation of the bark as it matures. It is nothing to worry about.
It is a true desert tree. Use an impulse sprinkler on it and soak it three to fives a year. That's how drought-tolerant desert trees are.
Paul planted a vegetable garden but it didn't yield any fruit:
Schilling: With tomatoes, you want to start them right after the first frost. You want to get them in the ground right away because somewhere, I think it is like 90 degrees, they stop setting fruit. They'll still continue to flower but the fruit won't set. You'll get your crop and then by June and July, you'll be done getting tomatoes.
Here's the key to veggie gardening in Southern Nevada. You know more than anything our challenge is our crappy soils - if you're not a desert plant.
So, build a raised bed... build it about 18 inches high... just go buy organic soil or get a bunch of organic amendment and then put in inline drip irrigation, half-inch inline irrigation with the emitters a foot apart, the tubes a foot apart, have a really good uniform wetting pattern.
Jen has a front yard with not much in and wants to know what mulch to put around the desert trees she's going to plant and whether she can put other plants under those trees.
Schilling: It's a desert tree, desert trees grow naturally in desert soils that is what we've got. You don't need to use any mulch other than the rock mulch that you have.
Yes, you can underplant. You can put other plants around the tree. Those plants have their own drip emitters... succulents, ground cover, other plants. You create a little eco-system.
Know that as the tree grows, it's going to start picking up water from those surrounding plants but I don't really see it as a problem for either one.
Kathryn has succulents that are looking scorched after the summer heat:
Schilling: They need shade here in the summer. They will fry. More often than not, succulents fail due to overwatering. You have two different things going on: potentially too much sun - and by the way, some succulents can take a lot of sun agaves and desert spoons and the like - but the some of the other succulents want some shade, they need some shade or they'll fry.
You can put a little shutoff valve on them or just hand water them just once a week or less in the summertime, but succulents fail with too much water.
From Nevada Public Radio: Desert Bloom
Norm Schilling, Schilling Horticulture, host of KNPR's "Desert Bloom"