What to do in your garden in July
• Bearded irises. Now is the best time to set out rhizomes of bearded irises. Plant in full sun (or light afternoon shade in hottest climates) and fast-draining soil. Set rhizomes 1 to 2 feet apart, and plant deep enough so the tops will be barely covered with soil. Two Northern California mail-order sources include the Beautiful View Iris Garden in El Dorado Hills ( www.beautiful-view-iris.com or 916/933-3804) and Brook Lomond Iris Farm in Ben Lomond ( members.cruzio.com/~irisfarm or 831/336-2203).
• Bigleaf hydrangeas. Most bigleaf hydrangeas produce flower buds on old wood formed during previous seasons. A few, classified as reblooming hydrangeas, bloom on old and new wood. These hydrangeas are great in any climate but do particularly well in areas where cold winters damage old wood. One outstanding new variety is ‘Endless Summer’, available at many nurseries. Flowers are pink on plants growing in alkaline soil, blue on plants in acidic soil. Another rebloomer to look for is ‘Madame Emile Mouillere’ (from Hydrangeas Plus, www.hydrangeasplus.com or 866/433-7896). Its white flowers have pink or blue eyes, and its petals become dotted with pink as they age.
• Patriotic pots. Using red, white, and blue annuals and perennials, plant a pot or two for Fourth of July celebrations. For the best effect, combine tall plants with shorter, bushier ones, then stick in trailing plants to spill over pot sides. For red choose from annual phlox, celosia, dahlia, flowering tobacco (Nicotiana), geranium, petunia, Salvia coccinea, or scarlet sage. White flowers to try include alyssum, annual phlox, dahlia, dwarf cosmos, flowering tobacco, geranium, heliotrope, nemesia, petunia, or a white variety of scarlet sage. For blue choose from gentian sage, lobelia, mealycup sage, nemesia, petunia, or verbena. All of these plants require full sun.
• Deadhead. To prolong flowering, pick off faded blooms, including the part where the seed forms. For plants such as marguerite and santolina that produce masses of flowers, save time by pruning with hedge or grass clippers.
• Fertilize cymbidiums. To encourage flower formation for next winter’s bloom, fertilize every time you water. Use a fertilizer specifically formulated for orchids (follow package directions). Or choose a soluble balanced type (such as 20-20-20) and dilute it to half the recommended rate.
• Fire protection. If you live in a fire-prone area, mow down wild grasses and weeds, leaving a wide swath around your property. Also trim dead growth from shrubs and trees, and prune any branches that overhang the eaves. Sweep leaves and debris from the roof.
• Control budworms. Sunset climate zones 7-9, 14-17: If your geraniums (Pelargoniums), nicotiana, penstemons, and petunias appear healthy but have no flowers, budworms are probably the culprits. Look for holes in flower buds and black droppings on the leaves. Spray affected plants every 7 to 10 days with Bacillus thuringiensis (Bt), available at most local nurseries and by mail from Harmony Farm Supply and Nursery (from $11; www.harmonyfarm.com or 707/823-9125).