Hi Angela,

Often times, annuals have been growing in pots for several months by the time we purchase them and are already mature. This is not uncommon in petunias. You can give this plant a bit of a 'haircut' by cutting the stems back by about half and giving it some water soluble fertilizer. You can also give it some slow release fertilizer that will feed it for the next several months. Both can be found at many garden centers, nurseries, box stores and farm supply stores. Be sure to follow the package directions for application rate and timing of fertilizing. 

This article shows how and where to cut back leggy plants. 

You're welcome. Good luck

Hi Angela,

No, you didn't kill your petunia. It has been really, really hot in Southeast Michigan and it has only been a couple of days. 

You may want to remove it from the hanging basket that it came in. Often times, those don't have enough space for all the roots. Instead of setting that white pot onto the large brown pot, go ahead and add potting mix to the brown pot. Remove the wire hangers, then invert the white pot so that the plants slide out. Set that plant mass into the filled brown pot and backfill around the plant mass with potting mix. Ensure that you have a good inch between the brown pot rim and the plant mass. That allows you to water it really really well. If you have a bit of mulch left over from your garden, you could add a couple handfuls to the top of the planter to help retain the moisture. 

Also be sure to give them a water soluble fertilizer according to the package directions. 

You're very welcome.