Unfortunately, we are not aware of a product which is labeled to control actively growing grass burrs or sand burrs that is also safe to be applied to bahia. What we typically recommend is that you spot treat as much as much as possible with a nonselective product (such as Roundup QuikPro) and then replant with the bahia in those areas in a couple of weeks when the grass/sandburrs are gone. To prevent any future growth of these weeds, you can apply a pre-emergent (such as Dimension 2EW) in the fall and spring.
Yes, Roundup QuikPRO will eliminate horsetail. Keep in mind that this is a non-selective herbicide so it will kill anything that it is sprayed on. Us caution if you are applying in an area where there is desireable vegetation present.
With Buffalograss being very tolerant to herbicides and St. Augustine/Centipede type lawns are very sensitive to herbicides, we recommend spot treating with a Glyphosate product such as Roundup QuikPRO. Spot treating will allow you focus your application directly to the targeted weeds and not damaging your grass. Roundup QuickPRO is a non-selective systemic herbicide and will only kill the weeds that are sprayed. It does not stay in the soil so any weeds that are beneath soil, will not be affected. Multiple applications may be needed. For further assistance on what the best herbicides are for treating buffalograss in your region, contact your local Master Gardener at the link below.
Master Gardener - http://npic.orst.edu/mgamlr.html
Unfortunately Centipede grass is so closely related to St. Augustine grass that there is nothing that will remove it and not hurt the Centipede as well. In your situation it is recommended to spot treat the unwanted grasses with Round Up and kill it directly, and then replant Centipede in those areas.
We do carry many professional Round Up products
