Leaf drop — River birches have been dropping leaves because of the hot weather, extension agent Bob Neier says. It's the way trees adapt, losing leaves so there's less for them to support.
Watering fruit and new trees and shrubs — Plunge a screwdriver or wooden dowel into the soil around fruit plants and recently planted trees and shrubs, gauging how moist they are by the resistance you meet. They should be moist about 12 inches down.
Deep, infrequent watering and mulching can help trees become established, Ward Upham of Kansas State says. You can set a hose to drip at the base of a tree for a few hours. Upham also gives this recommendation:
"Newly transplanted trees need at least 10 gallons of water per week, and on sandy soils they will need that much applied twice a week. The secret is getting that water to soak deeply into the soil, so it evaporates more slowly and is available to the tree's roots longer.
"One way to do this is to punch a small hole in the side of a 5-gallon bucket and fill it with water. Let the water dribble out slowly next to the tree. Refill the bucket once, and you have applied 10 gallons. Very large transplanted trees and trees that were transplanted two to three years ago will require more water."
Spider mites _ The first signs of both spider mites and leaf diseases in tomatoes are being seen in the demo garden at the Extension Center, extension agent Rebecca McMahon reports _ "which I suppose means that summer is really here!"
Spider mite damage appears as pale yellow or white stippling (very fine dots) on the leaves, she says. Severe infestations will leave webbing in the leaves, which will turn yellow. Manage mites by spraying a hard stream of water on the undersides of the leaves, or spraying under the leaves with a neem oil or horticultural oil, Rebecca says.
Tomato disease _ The leaf diseases usually appear as small black spots or larger brown 1/2-inch lesions on lower leaves of tomatoes, Rebecca says. The leaves quickly turn yellow and die, and the disease continues up the plants. Make sure your plants are caged or staked and mulched well, she says, and that you aren't getting the leaves wet in the evenings.
"The diseases spread by splashing water. Plants can be sprayed with chlorothalonil or a copper-based fungicide to prevent the spread of the disease."
Squash bugs — Squash bugs are the gray, shield-shaped bugs that feed on squash and pumpkin plants. Upham says. An insecticide such as permethrin, malathion, rotenone, or methoxychlor will provide control if it is directly applied to young, soft-bodied squash bugs, Upham says. This means that you MUST spray or dust the underside of the leaves, because this is where the insects live.
A late tomato season _ "Our plants are finally showing lots of blooms, so we're hopeful to have more tomatoes set in the coming weeks. Tomato season will just be a little later than usual this year," Rebecca says.
Fruit set _ Fruit set on squash, cucumbers and melon continues to be spotty, which is helped in cooler weather but slows when it gets hot again.
Potato harvest — Potatoes are ready to harvest when the vines are about half dead, Upham says. Don't delay digging, because the soil will heat up from the lack of foliage, leading to sprouting potatoes. Move the spuds to a cool, moist environment such as a cellar or cool basement for longer storage, Upham says.
Pulling onions — Onions are ready to harvest when about half the plants have tops that have fallen over. As with potatoes, you don't want them to sunburn without their foliage, Upham says. "The secret to onions keeping well is to allow the tops to dry completely before storage. Move onions to a shaded, well-ventilated area after harvest. After tops are completely dry, store in a cool, dry location. Large-necked onions take more time to dry than small-necked onions such as Bermuda types. Avoid storage in plastic bags, because the lack of air circulation will shorten storage life. Use an open, mesh bag instead."
Treat bagworms — Don't wait to see damage later in the month to treat bagworms. Look for the smaller versions of adult bagworms, and make sure they're alive before spraying, Upham says. Thorough spray coverage to foliage is essential. He lists these commonly used insecticides: (Orthene), permethrin (numerous trade names), cyfluthrin (Bayer Multi-Insect Killer), bifenthrin (Bug Blaster II, Bug-B-Gon Max Lawn and Garden Insect Killer), lambda-cyhalothrin (Spectracide Triazicide, Bonide Caterpillar Killer) and spinosad (Conserve; Borer, Bagworm, Leafminer and Tent Caterpillar Spray; and Captain Jack's Dead Bug Brew).
Summering strawberries — To boost your strawberry harvest next spring, take the advice of Upham: If you use a garden cultivator, rototiller or hoe for weed control in and between rows, throw about a half-inch of soil over the crowns. This provides a good rooting medium for new runner plants rather than allowing the soil to harden on the surface. Keep the soil moist. Strawberry plants need about 1 1/2 inches of moisture each week when temperatures reach 90 degrees.
Phoma blight on vinca — If you've had struggling vinca, it may have been affected by a stem/shoot disease called Phoma blight, Megan Kennelly of K-State says. The fungus takes off during wet spring weather, girdling the vinca stem and causing the entire shoot to die. The fungus should have dried up with the hot weather, and the diseased parts will dry out and fall off, Kennelly says.
Removing infected stems by hand may reduce the disease by removing the source of spores, she says. Avoid working in the beds when they are wet, to avoid spreading spores.
Lilies and Electric Lemonade _ That's the theme of Tuesdays on the Terrace next Tuesday at Botanica. You can buy drinks and hear Amanda Lind on the terrace from 5:30 to 7:30 p.m. Bring a picnic dinner if you like. The gardens are open until 8, including the new children's garden.
"Artists of the Children's Garden" talk — Jamee Ross, director of development for Botanica, will give the lunchtime lecture there Wednesday about the people who contributed their artwork to the new Downing Children's Garden. The lecture, at 12:15 p.m., is included in Botanical admission.
Lunch in the garden — Next Friday's subject is summer squash. Meet at 12:15 p.m. at the demo garden at 21st and Ridge Road.
Get your garden questions answered _ Master Gardeners will be on hand from 8 to 10 a.m. in the demonstration garden outside the Sedgwick County Extension Education Center at 21st and Ridge Road. They'll be ready to identify the plants growing there, demonstrate composting techniques and answer gardening questions.