Coastal and Tropical South
Summer can be hard on even the most durable ferns like southern shield (Thelypteris) and Christmas fern (Polystichum). They may grow pale or crispy as if they were going dormant, but it is simply the trials of midsummer. These and other hardy ferns can be rejuvenated easily with some organic nitrogen such as cottonseed meal and plenty of water. Snip off shriveled or broken fronds at ground level with scissors or flower snips to bring on new greens for fall.
Plant for fall
No matter how good or bad the spring garden proved to be, start the fall garden. Seeds and seedlings to plant right now include both flowers and vegetables to enjoy and harvest this fall. Parsley, cabbage, broccoli, and cauliflower may need shade for their first weeks in the vegetable garden, but will soon settle in and grow well. Zinnias, marigolds, and celosia come easily from seed now when planted directly in the ground.
Soggy potting soil or garden beds can bring on root problems. The first thing you'll notice may be tip burn on leaves. Use a fungicide drench to get it under control, clip off the damaged parts of the leaves, and repot container plants if necessary or ditch around the beds to improve drainage. Ignore the burn and soon leaves begin to drop, a real attention-getter, but also a sign that the situation needs to be addressed.
It's "off with their heads" for tired or leggy annual flowers, followed by fertilizer to get them blooming again. Impatiens, angelonia, and salvia recover rapidly from summer pruning so long as you fertilize and water regularly. If caladiums send up flower stalks, they will go dormant. Cut the spikes off and fertilize with fish emulsion or other nitrogen-containing fertilizer. It is this element that will promote leaves instead of flowers in caladium and elephant ear bulbs and other plants grown for their leaves, such as coleus.
Shear evergreens (but not flowering shrubs such as camellia and azalea) at midsummer to spur new growth, especially inside the shrubs' branchwork. Boxwood, yaupon and other little leafed hollies too easily become nearly naked except for their outer stems. Cut off as much as you want, so long as some green leaves are left to allow photosynthesis to continue. If leaves are much fewer at the base of the shrub than at the top, try this: prune so the base of the shrub is slightly wider than its top to let sunlight reach the entire plant.