Now that summer has arrived, I try to do harvesting and drying every week. The vigorous perennial herbs like mint, oregano, savory and tarragon can be cut back halfway and will quickly rebound. None of my basils are large enough to harvest yet, although they can be pinched back regularly (above where new leaves emerge) to provide fresh basil for the kitchen and also to produce a full and compact plant with lots of foliage. Basils and mints also prefer more moisture than many drought tolerant Mediterranean herbs like thyme and rosemary. I'm also harvesting chamomile flowers to dry for tea.
What's looking nice in the garden:
rose campion - shockingly bright magenta flowers against silver foliage
perennial salvia - purple arching flowers in a large clump
perennial geranium - tallish groundcover with lots of purple flowers and lasting blooms
clary sage - long lasting, still looks great
yarrow - all are blooming, yellow, pink, and white. I prefer the yellow for bunching and drying. Also good for drying - the Pearl - which is white and resembles baby's breath
hollyhock - flowers look great at the back of the bed, rust on leaves hidden
hydrangeas - still gorgeous
Speaking of hollyhocks, rust is an ongoing problem. Certain plants are susceptible to various fungus diseases like holly hocks and rust or bee balm and mildew. The spores are in the air and hot, humid weather allows them to thrive. You can spray ornamentals with fungicide, but it won't remove what is there, so for perfectly clean plants you must begin spraying before you see any disease. A lower-tech solution is to cut back bad foliage and new foliage will emerge and be clean - at least for a while. An organic solution I use in the greenhouse for mildew on rosemary is 1 teaspoon baking soda mixed in a quart of water and sprayed heavily on affected plants.