PLANTING
Bee allergies Gardeners are generally encouraged to attract bees and wasps to their plantscapes to pollinate all kinds of flowers, including those on some fruits and vegetables. But anyone with severe allergies may want to discourage the insects by selecting plants that don't attract bees. Choose fully double flowers with no landing areas for bees; moth-pollinated night-blooming plants, including datura, evening primroses (Oenothera), evening scented stock (Matthiola longipetala), flowering tobacco (Nicotiana alata), and four o'clock (Mirabilis jalapa); succulents that bloom infrequently, such as agaves and yuccas; ornamentals grown for colorful foliage, such as coleus, lamb's ears, and variegated cooking sage (cut off flower buds to prevent blooming); trees with inconspicuous flowers; needled evergreens; and ornamental grasses.

Great mountain plants Each year, Colorado State University and Denver Botanic Gardens' cooperative plant program, Plant Select, recognizes and distributes the best plants for the mountain region. Their 2008 choices include 'Blue Velvet' (deep violet) and 'Northern Lights' (lemon and lilac) pansies, two hardy varieties that bloom in spring with an encore from autumn through winter; 'Little Trudy' catnip (Nepeta), a very compact form with silvery foliage and lavender flowers; 'Mongolian Bells' clematis (Clematis integrifolia), a compact bush clematis that produces blue, lavender, pink, or white bells all summer; redbirds in a tree (Scrophularia macrantha), a Southwestern wildflower that attracts hummingbirds; 'St. Theresa Seedless' grape, which tolerates alkaline soils; and seven sons flower (Heptacodium miconioides), a small, adaptable tree with white flowers in late summer. Related story: Unthirsty color in Denver

Summer bulbs If your soil feels cool — but not icy — several inches below the surface, it's safe to get a head start on warm-season planting by setting out summer-flowering bulbs (which include corms, rhizomes, and tubers) two weeks before your last frost date; to check, call your local cooperative extension office. Set out bulbs or roots of agapanthus, Amaryllis belladonna, callas, cannas, dahlias, hardy gloxinia (Incarvillea delavayi), oxalis, pineapple flower (Eucomis), and poppy-flowered anemones (Anemone coronaria). Related story: The right bulb

MAINTENANCE
Control peach tree borers The immature (larval) stage of this borer is the most destructive pest of apricot, cherry, peach, plum, and ornamental species of Prunus trees in Colorado, Utah, and other mountain states. Larvae weaken or kill trees by tunneling into trunks at or just below the soil surface. If a tree is infested, you'll see clear sap mixed with dark excrement oozing out of the wounds. The pest is difficult to eradicate since it's protected inside the trunk. Keep trees healthy by watering and fertilizing regularly. Also, avoid damaging the lower trunk with lawn mowers and string trimmers. The best time to control borers is before the clearwing adults lay their eggs. Set out a peach tree borer trap by May 15 — one trap for each shrub or dwarf tree, two per mature tree. Traps are available from Gardens Alive; 513/354-1482. Related story: Gentle pest control

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