- Continue planting and transplanting perennials, adding a trowel full of compost to each newly dug hole.
- Thin the stems of late-blooming phlox and asters to the ground for larger flowers and less mildew problems later. Pinch back other late-blooming perennials.
- Monitor roses for black spot and keep up with a regular spray program.
- Plant summer annuals in among perennials and in containers. Nicotiana, verbena, salvia and ageratum all give lovely color variety. Cut back annuals by as much as half when planting, to reduce stress through water loss and to produce better branching and flowering. Fertilize with liquid fertilizer, measuring according to directions, shortly after planting.
- Zinnia, nasturtium and cosmos seeds can go directly into the garden.
- Set out dahlia tubers.
Vegetables and fruits
- If soil temperature is above 65 degrees, plant sweet corn now in blocks of at least four rows to insure good pollination.
- Continue thinning root crops, weeding, mulching and watering as needed.
- Resow lettuce, carrots, spinach and beets.
- If there is an overabundance of any vegetable, plant half rows and more varieties.
- Organic seeds, certified free of pesticide treatments, are now available at local garden centers.
- Remove flower stalks from rhubarb. Rhubarb can be cut in short pieces and frozen raw in plastic freezer bags.
- Sow basil and dill in the garden.
- Place marigolds near tomato plants for protection from pests.
Trees and shrubs
- Deutzias, forsythias and weigelas benefit from annual or biennial pruning shortly after flowering. Wait to prune hedges until later.
- Continue a regular schedule for applying deer repellents.
- Fertilize needle evergreens with an acid-type fertilizer.
- Mulch azaleas, rhododendrons and other ericaceous ornamentals.
- Complete fertilizing lawn and reseed bare spots.
- As night temperatures moderate into the 60s, move houseplants outdoors, avoiding full sun and windy locations. Repot as needed.
- Be vigilant about pulling out and destroying the biennial wild mustard. This is a very invasive weed with bright green leaves and small white blossoms on top. It is overrunning the forests with damaging results. Another invasive, purple loosestrife, will appear in the summer, and should also be eradicated.
Susan Henry, master gardener