Ask Mr. Smarty Plants

You are absolutely right, and since the Lady Bird Johnson Wildflower Center is dedicated to the growth, propagation and protections of plants native not only to North America but the area in which the plant is being grown, you can get a clue, if not necessarily the exact zone, from knowing if that plant is native to your area. This has been a question asked several times recently, which probably means people are tired of buying gorgeous blooming plants, only have them broil or freeze to death when they get in the garden.

Many plants that are commercially available provide no information on where the plant might be hardy, and plants are sometimes sold in areas where those plants are not hardy, and will take a dive in the first cold spell or heatwave.

It is not presently possible to search our database by hardiness zones, hopefully we will get to that one of these days. The Native Plant database is a work in progress and always will be. So, let us give you a tutorial in how we determine hardiness zones. First, look at our database page on the plant you are interested in. If it is not native to your state, that's a first clue. To narrow that down, you can determine where in the state you are located. For us, who only know where most Texas counties are located, we Google on the name of the town and state. Wikipedia is the best and fastest way to get information. They will tell you what county the town is in and also have a map with the location of the town. We note the name and location of that county, and then go to a USDA Zone Hardiness Map. There are several of these available, but we like this one, because you can view state by state, instead of the whole map.

Assuming we are trying to find out what zone you are in, we first determined that Springdale AR is in northwest Arkansas, in Washington and Benton Counties. Then we go to the Zone Hardiness Map, click on "AR" and find that most of the northwestern area of Arkansas, including the above two counties, is in Zone 6b. Next, we will go to the USDA Plant Profile for the plant in question, for instance, Asclepias tuberosa (Butterflyweed), which is a great plant for attracting butterflies. We went to the USDA Plant Profile Map for Arkansas, and found that Butterflyweed is being grown in your region. At the bottom of our page on each plant, you will find a link to the USDA Plant Profile on the plant you are considering. When you go to that map, click on your state.

This is a process that we go through for virtually every plant we recommend. The fact that it grows in your county not only tells you the climate is appropriate for your plant, but that there is a good possibility that the soils and rainfall are also in a good range for that plant to flourish.

If you really want the approximate zone you are in, you can search on the Internet for other sites on that plant. Many will give you a zone range, such as 7 to 9. Again, go to the bottom of the page on your plant in our website, and click on the link to Google.

So, you can search on our website for plants native to your state, find out the sunlight requirements, soils preferred, soil moisture needed and height of the mature plant. Then, with just another minute or so, you'll have the zone. Remember, those hardiness zones are very approximate; if you are in a mountainous area where elevations rapidly change, or have micro-climates of seashore or drought area, getting the exact zone is not possible, but you can get close.