Franz Schubert Phlox reblooming after deadheading
Blue Paradise reblooming
Laura getting ready to rebloom
I am also a proponent of deadheading plants that do not necessarily give you new blooms but do put up a flush of new green leaf growth. It prevents that tired look at the end of the growing season where everything turns a shade of brown.
Arnie's Choice Daylily sprouts new foliage after being cut to the ground, plumbago, a fall blooming groundcover underneath.
Becky Shasta Daily sprouts new foliage after being cut to the ground.
Certain plants, at least in my zone 5 area benefit by being left to stand during the winter. They can be deadheaded but should not be cut to the ground as we do with many other perennials. Agastache and Centranthus are more reliable if they are not trimmed to the ground, lavender also should only be trimmed in the spring to new growth.
Agastache Rosita benefits from deadheading all summer, continual flowering. Leave this plant standing for the winter, cut down a little for neatness but do not cut to the ground.
Agastache Blue Fortune
Gaillardia Mesa can be deadheaded all season for continual bloom. This plant can be trimmed low in the fall.
The above plants are all waterwise and are some of the plants from the alley garden. They have done very well obviously because they do not require much water and love the heat.
Most other perennials and grasses can be trimmed to the ground in the fall without any ill effects, unless you want the winter interest of seed heads. I would not recommend leaving the Miscanthus grasses up for the fall and winter. They do not hold up to the snow and become quite messy and labor intensive the following spring. Even my Carex on the north side of my house is a major problem to cut back if we do not do it in the fall - it becomes mushy.. Panicum Northwind is the exception in that it turns a tan in the fall and stands very well through snowstorms and most of the winter until March. This grass is not a problem cutting down in the spring.
Panicum Northwind can be left standing for the winter. It becomes tan in the fall and can withstand snow and ice until March.
Miscanthus Udine will flop if not cut down in the fall.
Pennisetum Hamlin does not need to be cut back for the winter.
Carex Ice Fountains requires cutting back in the fall
If you have hydrangeas that bloom on old and new wood you can leave them dried on the stems for winter interest and cut them down in the spring. Limelight, Endless Summer, Unique, Pink Diamonds are just a few varieties that bloom on old and new wood.