[Note: all of the photos will supersize if you click on the picture]
When you park in the driveway, the first thing you run into (literally) are a cluster of plants for butterflies. At the back, emerging from the worst possible soil (gravel mulch) are a dozen milkweed plants (a late-summer photo already showing seed pods.) In front of that are purple coneflowers; butterflies love it as a nectar plant. The sage that is admixed with the coneflowers has minuscule blossoms that attract a variety of bees and other tiny pollinators.
Going up the sidewalk requires passing a gauntlet of flowers reaching for sunlight (a crabapple tree on the left shades that part of the garden). The Rudbeckia (Black-Eyed Susan) is extraordinarily easy to grow; these plants are also emerging from a gravel mulch.
That same bed from the lawn side is dense with Monarda in late summer; they have overgrown the lilies that were blooming there in the spring and early summer. The phlox is tall enough to hold its own, and the balloon flowers (Campanula) are reaching out for sunlight away from the crabapple. More milkweed at the back.
One more bed for butterflies. The pussytoes (Antennaria sp.) at the bottom is the favorite food plant for the American Lady butterfly. That cluster of plants will harbor a dozen caterpillars during the summer (most of whom will fall victim to spiders unless I rescue them). Behind them more milkweed and the usual nectar plants. And a bed of not-yet-blooming goldenrod; some people view it as a weed, but it is a marvelous plant for butterflies and especially for bees in the autumn when so many other nectar sources are dying.
I absolutely love New England asters. Again, easy as pie to grow. AFAIK, not a food plant unless maybe for some moths, but a great nectar plant for that late-season time when other plants are dying. And the palette of colors is eye-catching.
Lastly a composite of pix of individual plants. The Rudbeckia and coneflowers we met earlier. The milkweed upper right shows the resilience of that species, emerging from stones and gravel next to a brick wall. Bottom left, jonquils graced with a late dusting of snow. We plant jonquils and crocus right in the middle of our yard; they emerge early spring and we mow around them a time or two, then they fade away or get consumed by the rabbits. Lastly one of the bearded irises. Complex blossoms like these are of little or no interest to butterflies. Large bees (bumblebees) will climb in, but we love them for the awesomely complex structure and patterns of the blossoms.
These gardens are in Madison, Wisconsin, which is at a latitude similar to Boston, but because we are midcontinent, we are in plant hardiness zone 4b (minimum temps 30 below zero) - more equivalent to upstate New Hampshire than to your Boston area, which benefits from the thermal buffer of the ocean nearby. But I think all these plants would grow in your gardens