The nice thing about Silverado is that is is a compact type of Texas Sage. Your plant is just getting established and developing a root system that is extensive. Next year it will grow faster so don't worry about it being okay.
I don't think a weed and feed is needed in most cases. You generally will need to put down a pre-emergence weed killer about the third week of September in your area. Fertilizing can best be done about the first or second week of October. If you don't have ongoing weed problems I would avoid the weed killers as many can be stressful and damaging to turfgrass. Focus on good mowing, watering and fertilizing practices to build a dense healthy lawn and most of your weed problems will go away.
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