Some random thoughts...
You've certainly given yourself the hardest challenges to start with -- flowers in situ, and white blossoms in bright or dappled light! There's a reason Mapplethorpe, Penn and others did studio shots of flowers. I like that you've found dark and distant background for the first shot. It's terribly difficult with some smaller blooms, like the second. And delicate blooms will move with the slightest of breezes (don't exhale!). The worst I've encountered is the white Trillium in Ontario. First, it's "protected", so you can't pick one and bring it home. Second, it's always poking up through unattractive brown forest detritus. Finally, the surrounding trees almost always provide dappled light unless it's overcast.
I know one dedicated flower guy who has built himself a portable screen made from three garden stakes with semi translucent fabric between them. He uses it to block the breeze, and sometimes to soften the direct light, or provide a soft, reflected fill. It's light and portable (he just rolls them up). I haven't tried that, but I have used the translucent screen from a 5-in-1 reflector to soften harsh light, and the reflector to fill in shadows or even to provide a reflected main light. However, I've been much more successful bringing tulips and irises and other blooms inside to photograph. And I've found that some blooms are just as interesting as they die back, as when fresh.
I use macro lenses, but I know that some people have excellent results from good quality close-up filters (e.g. Canon 500D).
IMO, I don't think that the "soft filter" effect has compensated for the lack of sharpness in these examples. I have applied a 'glow' to some sharp images, but this is the opposite situation. I think you need a dominant focal point for the eye that is clearly in sharp focus.
Flowers! Who knew they could be so challenging?
