Roses are fairly safe, so long as they haven't been sprayed with pesticides. However, any type of lily or tulip - basically anything that grows from a bulb - is very toxic to cats!
And be VERY careful about those little pots of crocus appearing in grocery stores right now, to tempt us out of the winter doldrums - their grassy-but-toxic leaves are way too tempting for cats!
If you do have live flowers in your house, the best bet is to put them somewhere that your pets cannot reach them.
For a full list of the most-toxic plants to cats, as identified by the ASPCA, please visit this link where I discuss them in more detail.
Have a SAFE & Happy Valentine's Weekend,