Perennials: If mildew persists on phlox, zinnias and roses, use ultra-fine oil. Cut off the stalks of hostas and day lilies that have already bloomed. Now through autumn is a good time to plant peonies. Enrich the soil, give them plenty of room in full sun and well-drained soil. It is not too late to order fall blooming bulbs to plant in in September and October.
Flowers: Continue feeding annuals. They will provide deeper, more intense color in early fall. Fragrant heliotrope, vivid dahlias, airy cosmos along with spiky blue salvias make a striking late summer bouquet.
Vegetables and fruits: Don’t be in a hurry to harvest onions. The tops fall over and turn yellow when they have stopped growing. Continue planting leafy greens. Arugula tastes sweeter growing in cool weather. Mesclun lettuce grows quickly and can be grown in patches as well as rows. For best flavor, broccoli and cauliflower must be picked before flower clusters appear. However, if they do flower they will attract beneficial insects. Continue to spray apples with all-purpose spray until two weeks before harvest. Pick cantaloupe when the skin has turned from greenish to tan. It should smell sweet and pull easily from the vine. Ripe watermelon will have a hollow sound when thumped and the skin will lose its shine.
Trees and shrubs: Plant broad leaved and needled leaved evergreens from late August through Oct. 15. Move mulches 2 or 3 inches away from the base of established plantings. The basal stems need time to harden off without contact with the mulch.
Lawns: Consider sod to repair bare patches. Take a soil test before seeding new lawn areas. If an excessive amount of thatch has accumulated use a power rake or thatcher to remove it.
Houseplants: Maintain vigor by regular watering and fertilizing. Examine for pests.
General: Homeowners apply an estimated 66 million pounds of herbicides and insecticides per year to their homes, gardens and lawns.
Susan Henry, master gardener, Cornell Cooperative Extension of Westchester