They're so pretty even though they're weedy - mine seed everywhere if I let them! Which actually means they aren't shasta daisies anymore because shastas are supposed to be sterile. Shasta daisies can revert back to the parent plant, ox-eye daisy, which is a weed. So even though they're pretty, I cut these back as soon as the first flush of flowers is starting to finish so that they don't seed all over the place.
How do you tell the difference between a shasta and an ox-eye? Well, it can be difficult. Especially since reverted shastas can crossbreed with ox-eye, resulting in a hybrid that is difficult to distinguish from either parent, and can also be invasive. One presenter I listened to once said that the ox-eye has a spoon-shaped leaf and the shasta a tongue-shaped leaf, but then showed photos the opposite way around, so even she seemed confused! And pictures of the ox-eye leaves from Alberta Invasive Plants look tongue-shaped if you ask me. In fact, what I have is probably a hybrid and thus I cut it to the ground before it starts to set seed just to be safe. But technically I should probably get rid of it.
Other perennials also blooming right now: blue salvia 'May Night'; several varieties of achillea (yarrow); campanula glomerata; nepeta (catmint) 'Walker's Low'; veronica spicata 'Sunny Border Blue'; potentilla 'Miss Wilmott'; and an unknown variety of white phlox which is just starting to flower.
To see this garden at other times of the year and how it has evolved, click here.