Weed around the blueberry bushes, then fertilize with a granular fertilizer, such as 4-6-6 or 8-10-10, and ammonium sulfate, mixing two parts of the first with one part of the latter. Apply two handfuls to each plant, then apply 3 inches of mulch, using shavings or composted chicken manure. Feed again in two weeks with a balanced liquid fertilizer.
Deadhead Rhododendrons and Azaleas
When rhododendrons and azaleas have finished blooming, remove the faded flower stems. Be careful to avoid damaging the buds and new growth below. The task is tedious, but this prevents the plant from setting seed, which takes energy away from the new growth and next year's flowers. Remove the entire growing tip if you want plants to be bushier.
Pinch Back Mums and Asters
Pinching out the stem tips on asters and chrysanthemums several times before early July encourages branching, makes the plants shorter and bushier, and increases flower bud production. Weed around plants, work in some fertilizer, then mulch. One of the best asters to try is 'Monch'. There are also low-growing types, such as 'Wood's Purple', that are naturally dwarf.
Aphids are at their worst right now, clustering on young, succulent growth and the undersides of leaves. The tiny, soft-bodied insects are usually pale green, but may also be pink, black, or yellow. They're especially bad on ornamental honeysuckle vines as well as young vegetables. Spray with a liquid soap solution or a preparation containing pyrethrum, making sure the leaf undersides are wetted.
Experiment with Tender Bulbs
There's a wealth of tender bulbs that bring color and fragrance to the garden. Their only downside is they have to be dug up in the fall and stored over the winter indoors. Tuberoses head the list because of their rich scent, but also consider tigridias, montbretias, zephyr lilies, caladiums, and cannas.