PLANTING AND SHOPPING
• Fill color gaps in beds, containers. When cool-season flowers stop blooming, cut them back and fill the gaps with heat-loving annuals such as Angelonia (for more on this plant, see "Summer Coolers" on page 64), celosia, coleus, Evolvulus glomeratus, gazania, globe amaranth, Madagascar periwinkle, marigold, ornamental pepper, petunia, portulaca, star clusters (Pentas lanceolata), sunflower, and zinnia.
• Set out heat-loving perennials. Many perennial flowers stop blooming when temperatures exceed 90°, but for color that stands up to summer's heat, try Agastache barberi, baby's breath (Gypsophila paniculata), bee balm (Monarda didyma), Coreopsis verticillata, daylily, German statice (Goniolimon tataricum), globe thistle (Echinops), mallow ( Malva alcea 'Fastigiata'), Mexican evening primrose ( Oenothera speciosa 'Siskiyou'), purple coneflower, Sedum spurium, Shasta daisy, Veronica 'Sunny Border Blue', wine cups (Callirhoe involucrata), and yarrow ( Achillea filipendulina, A. millefolium, A. 'Moonshine').
• Shop for spring-blooming bulbs. Order now from mail-order catalogs and online suppliers so bulbs will be shipped at the proper planting time for your area. The following species will naturalize in unirrigated plantings: Allium caeruleum, A. karataviense, A. senescens; Calochortus; Crocus ancyrensis, C. chrysanthus, C. vernus; Fritillaria persica; Iris danfordiae, I. histrioides, I. reticulata; grape hyacinth (Muscari); tulips (Tulipa batalinii, T. humilis, T. linifolia, T. pulchella, T. urumiensis). A good source is John Scheepers ( www.johnscheepers.com or 860/567-0838).
• Control powdery mildew. One warm, humid summer day is all it takes to trigger an outbreak of powdery mildew, a fungus that causes leaves to look as if they have been sprinkled with talcum powder. To prevent infection in susceptible plants, regularly rinse foliage with a hose to wash off spores. Or spray leaves with liquid sulfur or neem oil every 7 to 10 days from midsummer to autumn.
• Foil corn earworms. This caterpillar ― which can range from tan to green to pink with stripes ― damages sweet corn by chewing through the silk tassels and into the kernels. To protect against this pest, use a medicine dropper to put a drop of mineral oil on the silk of each ear of corn just after the silk starts to turn brown.
• Go online for drought guidance. In early spring, severe summer drought was forecast for much of Idaho and Montana. For low-water landscaping guidance, Xeriscape Colorado www.xeriscape.org is the most complete source. Help is also available from Utah State University Extension extension.usu.edu/drought.
• Spread coffee grounds. Starbucks coffeehouses provide free bags of used coffee grounds for gardeners (just ask at the counter). Spread the grounds directly over garden soil, or add them to the compost pile.
• Watch for squash bugs. These angular, roughly 5/8-inch-long black-and-gray bugs can destroy both foliage and developing fruits on squash. Sprinkle diatomaceous earth beneath the plants to repel the bugs. Check the undersides of leaves for shiny brown egg masses; remove and crush them. To trap adult bugs, place a board near squash plants in the evening. The next day, lift the board and destroy the bugs hiding underneath.