I'm looking to grow some Coreopsis/tickseed plants in containers on my balcony, mostly to attract birds and pollinators but also for their visual appeal. An employee at the plant store suggested varieties "Zagreb" and "Moonbeam" as being closer to the native, uncultivated flower (lines up with this recommendation about using nativars vs natural varietes https://gardening.stackexchange.com/a/57236/24416). However, the Zagreb and Moonbeam coreopsis on sale are notably more stringy and kind of all over the place compared to the other varieties, which have pretty and compact foliage. On the other hand, googling these varieties shows me images of lovely foliage just like the other varieties I saw on sale.
My question is: Are the less cultivated varieties of coreopsis naturally very loose and diffuse, or was I just looking at a bad bunch that maybe needed to stretch for some extra sun in the nursery?