Ask Mr. Smarty Plants

Agave tequilana, Blue Agave, is native to Jalisco, Mexico, the world capital of Tequila, which is distilled from the agave. The Lady Bird Johnson Wildflower Center is dedicated to the growth, protection and propagation of plants native not only to North America but to the area in which those plants are being grown. It is hardy from USDA Hardiness Zones 9b to 11, and likes high altitudes. Since it is not native, we do not have it in our Native Plant Database, but have found some information on it for you.

From a previous Mr. Smarty Plants answer, here is an answer about an agave having freeze damage, although not the Blue Agave:

"What to do?  If you want to try to salvage the plant, carefully remove  the dead material so that healthy tissue can regenerate. Usually the first stage is the formation of callus tissue which will give rise to new tissue. Your plant may be too far gone, but with a little patience, you could possibly revive it."

From the Succulent Plant Page website, we extracted this information.

"Agave tequilana  F.A.C. Weber 1902
is perhaps the most important Agave for it is from the emerging flower spike of this plant that Tequila is made. It originates from the state of Tequila in Mexico, where selected clones are grown commercially. This species may be seen bedded out as a large specimen plant in warm climates.
 
The bluish leaves have finely toothed margins. The inflorescence of this specimen was taller than the Princess of Wales Conservatory at RBG Kew."

The major problem is that Lockhart is in USDA Hardiness Zone 8b, as is most of Central Texas, which means that agave might freeze again. Perhaps it will come back, but we would recommend not planting another one in that spot. If you are determined to have an agave, Agave americana (American century plant) is the only native agave hardy to this area.

Pictures of Blue Agave from Google