What to do in your garden in July

MARCIA TATROE,  – May 24, 2005


Fill color gaps in beds, containers. When cool-seasonflowers stop blooming, cut them back and fill the gaps withheat-loving annuals such as Angelonia (for more on this plant, see “Summer Coolers” onpage 64), celosia, coleus, Evolvulus glomeratus, gazania, globe amaranth, Madagascarperiwinkle, marigold, ornamental pepper, petunia, portulaca, starclusters (Pentas lanceolata), sunflower, and zinnia.

Set out heat-loving perennials. Many perennial flowers stopblooming when temperatures exceed 90°, but for color thatstands 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-ordercatalogs and online suppliers so bulbs will be shipped at theproper planting time for your area. The following species willnaturalize 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 or860/567-0838).


Control powdery mildew. One warm, humid summer day is all ittakes to trigger an outbreak of powdery mildew, a fungus thatcauses leaves to look as if they have been sprinkled with talcumpowder. To prevent infection in susceptible plants, regularly rinsefoliage with a hose to wash off spores. Or spray leaves with liquidsulfur or neem oil every 7 to 10 days from midsummer to autumn.

Foil corn earworms. This caterpillar ― which can rangefrom tan to green to pink with stripes ― damages sweet cornby chewing through the silk tassels and into the kernels. Toprotect against this pest, use a medicine dropper to put a drop ofmineral oil on the silk of each ear of corn just after the silkstarts to turn brown.

Go online for drought guidance. In early spring, severesummer drought was forecast for much of Idaho and Montana. Forlow-water landscaping guidance, Xeriscape Colorado www.xeriscape.org is the mostcomplete source. Help is also available from Utah State UniversityExtension extension.usu.edu/drought.

Spread coffee grounds. Starbucks coffeehouses provide freebags of used coffee grounds for gardeners (just ask at thecounter). Spread the grounds directly over garden soil, or add themto the compost pile.

Watch for squash bugs. These angular, roughly 5/8-inch-longblack-and-gray bugs can destroy both foliage and developing fruitson squash. Sprinkle diatomaceous earth beneath the plants to repelthe bugs. Check the undersides of leaves for shiny brown eggmasses; remove and crush them. To trap adult bugs, place a boardnear squash plants in the evening. The next day, lift the board anddestroy the bugs hiding underneath.