Be sure to pick the right plants for your zone
Despite the record-breaking cold we’ve had, this balmy spring interlude has me thinking about my landscaping. I’ve learned the hard way to stick with native plants, or naturalized plants that withstand our harsh summers. I’ve also learned to narrow that list down further to choosing the right plants for my climate.
Not only does this save money, because you don’t have to replace dead plants, but in the long run you save on water and fertilization costs. Maintenance is just easier. Putting plants with the same sun/shade and watering requirements together sounds like a no brainer. However, I’ve seen many a yard with something that requires practically no water, like an agave, surrounded by petunias. Sure it looks pretty at first, but eventually something’s gotta give, and it will be the petunias, which cost more as a whole and took more time and effort to plant.
Everyone’s seen the plant tags that detail the sun/shade, water, and temperature requirements. It’s important to read these, but here’s a word of caution. I’ve found in my experience that a plant that takes part sun/part shade really means “mostly shade with a little bit of morning to afternoon sun”. The sun here is just too hot.
The other thing you may see is the rating the plant has on the USDA Hardiness Map. This map breaks the U.S. into twelve zones defining the average annual minimum temperature for that area. The lower the number, the lower the minimum temperature. We’re in Zone 8, which has an average annual minimum temperature of ten to twenty degrees. Any plant from Zone 8 to Zone 1 will survive our winters.
But, winter isn’t our problem. It’s summer. So, there is another map, called the Heat Zone Map, created by the American Horticultural Society. This map also has twelve zones, but it shows the average number of days a year in which the temperature is over eighty-six degrees. Zone 1 is less than one day. Zone 12 is more than 210 days.
We are in Heat Zone 9 where the average number of days above eighty-six is 120 to 150. So, when you see numbers like this on the plant sticker: 3-8, 8-1; that means that this plant can survive USDA Zone 3-8 and Heat Zone 8-1. It will live through our winters, but have a hard time making it through our summers.
Texas Agrilife has two helpful programs that recommend plants for all areas of Texas. One of those programs is Earth- Kind Landscaping. Earth-Kind promotes the conservation of water and energy, reduction of fertilizer and pesticide use, and reduction of the amount of yard waste going to landfills.
The Earth-Kind approach doesn’t stop with plant selection, but continues as you move into maintenance mode. However, you will see plants with an “Earth-Kind” designation. The first plants to undergo testing and certification as “Earth-Kind” were roses. These roses underwent eight years of research and testing, and finally four years of field trials throughout Texas to see which ones survived with no fertilizer; had superior pest tolerance; and adapted to a wide range of soil types, and, finally, be extremely heat and drought tolerant.
Another Agrilife program is the Texas Superstars. These plants were also tested to see which ones were adaptable statewide. Note that Earth-Kind does not equal Texas Superstar. Whereas Texas Superstars can grow pretty much anywhere in Texas, many Earth-Kind plants are suitable only to particular areas.
Texas Agrilife provides searchable plant databases for both Earth-Kind and Texas Superstars. When using these databases, keep in mind the zones you live in and the planting requirements for your yard. For more information, check out aggie-horticulture.tamu.edu/, aggie-horticulture.tamu.edu/, earthkind/roses/cultivars/ or www.texassuperstar.com.