When did Obama know about this, and what did he know?
Obama’s fault.
But seriously, this IS a real issue. For once the Guardian is reporting well.
If you want bees, native bees do a good job. If you want native bees, they need pollen, all year (except in winter). For a variety of complex reasons, native bees don't find most exotic plants very attractive. That means maintaining native plants that flower in successive cycles. Unfortunately, exotic weeds are displacing said native plants nationwide. Few do much of anything about it. Developing the knowledge of the plants they prefer and how to grow them is what we are doing here, now.
The idea that Nature exists without people on the land caring for it may be the most destructive precept ever promulgated.