MS. REBECCA SHEIR
Welcome back to "Metro Connection." I'm Rebecca Sheir and today we are Feeling the Heat. But of course, we humans aren't the only ones who feel the heat when the thermometer rises. That's why our environment reporter and part-time gardener, Sabri Ben-Achour, headed to the U.S. Botanic Gardens to find out how we can beat the heat for our plants.
MR. SABRI BEN-ACHOUR
So if a car in the sun can reach temperatures of 200 degrees Fahrenheit, according to the National Oceanic and Atmospheric Administration, how do greenhouses do it? I mean, they're basically big glass cars. Jim Kaufmann helps run the nation's greenhouse at the U.S. Botanic Garden. I met him in the Orchid House.
MR. JIM KAUFMANN
The really neat part about this house is that if you look above us and around us, is that we're surrounded by a big fichus and this is natural cooling at its best. The canopy covers up the entire house.
Yes, there are roots dangling around us right now.
We're draping through the aerial roots.
But sometimes even the botanic garden needs extra help so they have vents in the ceiling and special misters and underground vents to push cooler air up. But most people don't have those things so what are we supposed to do? You might be saying, duh, just water your plants, but Kaufmann says that's not necessarily a good idea.
Sometimes some plants get so hot that they just stop taking up the water and they...
They just kind of shut down.
...just kind of shut down. You know, just like anybody else. It gets so hot, they're not working anymore.
The problem is hot soil and you can have hot soil that's wet and ends up just drowning your plant. So Kaufmann says don't boil your plants.
Probably the most important thing that I'd like to stress is feel the soil. The soil is so important. Take the mulch aside and you reach in right around the roots, where the roots are, and you just take a fist full. If you can take that soil and squeeze it in your hand and it retains that shape of your fist, you're at a good soil moisture and you probably have a good soil texture in there. If you start to see water drain out of there when you squeeze it in your fist, you've got too much water going on there and if it just crumbles apart, you're probably too dry.
He says one great idea to keep the soil cool is mulch, two or three inches of it, but again, he says, there is such a thing as too much of a good thing.
A typical thing that I see a lot of around here is what I call the mulch volcanoes, where some folks will take shredded hardwood mulch and build it a foot or more up around the base of a tree. You never want to do that.
That's because what rots mulch could rot the bark on your tree. But fundamentally when it comes to beating the heat, maybe the best strategy is to not try so hard. That means picking your plants wisely. Outside the greenhouse, Kaufmann uses a lot of native plants.
You'll see plants like the long-leaf pine with the long green needles are probably about a foot long. As far as perennials, I got to say some of the Echinacea, just anything you can throw at Echinacea, it can really take. You'll see them in purples, whites, green, there's a beautiful one called Green Envy. Echinacea and a variety of ornamental grasses really make a good combination.
Thyme, he says, is a really tough plant and a good bet. So are a lot of herbs like rosemary. For annuals, there are some really resilient ones, too.
Those tough annuals, some of my favorite are Lantanas and Coleus. They take all sorts of conditions and they go from oranges, yellows, multi-colors and then the Coleus's there's a variety of textures of leafs from, looks like duck's webbed feet to some really dark almost black leaves.
You're not going to beat Mother Nature, says Kaufmann, so you got to figure out ways to work with her. So the best way to beat the heat is to use plants that love that. I'm Sabri Ben-Achour.
You can find a list of some of the resilient plants Kaufmann recommends on our website, that's metroconnection.org.
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