Late summer perennials:
As larger perennials are done blooming, start cutting them back to the ground: some will develop fresh new foliage for the remainder of the season. Sometimes they manage to bloom again before the frost. To neaten their appearance, cut leggy stems of plants like Coneflower, Daisies, Black eye Susan, Hosta, and Daylilies. To extend the perennial garden into the fall, plant fall Chrysanthemums, and Asters; these are available at garden centers by mid-August. Also try planting fall Pansies and Ornamental Kale and Cabbages to extend your season even after the frost.
Creating a butterfly garden involves planting nectar-producing plants to encourage butterfly populations to visit. The goal is to provide flowers in bloom thought out the season, especially during mid to late summer when most butterflies are active. Flowers with multiple florets that produce a lot of nectar are ideal to keep new butterflies visiting your garden. The two best plants are butterfly bush and butterfly weed; other good shrubs are Rose of Sharon, Spiraea, and Clethra. There are also a lot of perennials that do a good job of attracting butterflies like Coneflower, Aster, Bee-balm, Black eye Susan, Coreopsis, Daisy, Liatris, Lantana, Mountain mint, Hollyhock, Phlox, Salvias, Sedums, and Yarrow. All butterflies have pacific host plants, these plants are for the adult female butterfly to lay her eggs. When these tiny caterpillars hatch they cannot travel very far to find food, the female lays her eggs on only plants that support these young caterpillars.
Fall webworm is a native insect and most severely attacks native plants. This list includes Black Cherry, Walnut, Hickory, Redbud and Mulberry. This caterpillar has a distinct mass of webbing and can be very destructive and able to defoliate entire plants. Pruning out the small webs is a good option since there are some natural parasites that feed on these caterpillars like birds, wasps and yellowjackets. Spraying into the large nests has limited effectiveness; the damage this late in the season is mainly aesthetic.
The pre-emergent that was applied in spring is gone by now; most of these products have a life of about 60 to 90 days. This can depend on weather and moisture. The application of this pre-emergent herbicide should be done by the end of August. As the nights get cooler, these winter annual weeds tend to germinate a lot faster. This group of weeds includes henbit, field violets, chickweed, and mustard family.