There is an old saying attributed to the agricultural Texas Indians, the Caddos in East Texas and the Wichitas along the lower Bosque River, that sweet corn can be planted as soon as post oak leaves grow to the size of squirrel’s ears. Pictured above is a twig showing emerging post oak leaves just a little smaller than a squirrel’s ear (I haven’t examined a squirrel’s ear lately, but I think they are about a quarter-inch). When they age just a few more days it will be time not only to plant sweet corn, but pepper, tomatoes, and the like can be set out without too much fear of a late freeze (just hailstorms and drought).