Raise the Hammer

There are perennials that bloom for most of the season & all that's required is somebody to clip off the seed heads. (roses, & true daisys, =coreopsis to name a few.)

There are annuals that grow quickly from seed (for pennys a plot) like cosmos, & California poppys = Escholtzia to name a few. These flowers also tend to re-seed themselves for free & they flower from late June/early July until hard frost. They are also deep rooted & drought resistant once established & save watering costs.)

Perennials with long flowering seasons, like the cone flowers,& hydrangea shrubs can look great long after they have flowered because the flower heads dry on the stems. They are also deep rooted & drought resistant.

Borders of the beds & dividers could have some annuals for season long colour, but these could be supplimented by perennials. Buying only 1/4 or less annual plants would lower costs.)
Perennials plants with interesting leaves & like sedums, variegated iris,day lilys, flowering grasses & many other provide interest all season & into the winter.

The only downside i can see to perennial plants in city gardens & street dividers is theft.
We could save much money by planting only once in the spring, & save more money by using deep rooted perenniels, drought resistant annuals, interesting shrubs, & flowering shrubs that do not need the constant watering & attention/fertilizers that tender annuals do. If watering is necessary, someone could also clip off the flower heads at that time to produce more blooms.

I have never understood Why we have opted to only go with annuals, & then cry poor, & fill places with rocks. The cost of a few perennials would likely be cheaper than the rocks. The rocks sprout weeds if there is even a trace of soil under them, so unless we are prepared to pave deeply under these 'rock gardens' to a depth of a metre or more, they will always be a weedy mess. (which is more $ maintenance $)

(Some garden groups used to provide volunteer services to their town. Either these folks are unavailable to do this anymore, or this portion of civic pride disappeared with amalgamation-? Heavier traffic has certainly made that a much more dangerous activity to undertake as a volunteer.)