This week in your Massachusetts garden & landscape

Be cautious when dining outdoors, a la barbecue or picnic, with family or friends.  I’m not suggesting there’s anything unsavory about your family and friends, though I’ve had my suspicions.  Actually, it’s the uninvited guests that concern me most, in particular yellow jackets and bald faced hornets; their populations are now at a peak.  Wasps love to attend picnics.  Maybe that’s why they are called social insects.  Wasps are especially fond of fruit salad and sweet drinks.  They get so giddy; some will even dive right into an open can or bottle of soda pop.  Now there’s fat lip awaiting an unsuspecting soda sipper.  While wasp stings are painful in themselves, the greater danger is to people who are allergic to the stings.  It’s not just picnics with unsavory …..uh, family and friends that one has to worry about. Anybody working outdoors near shrubbery, stone walls, and wood piles, should be aware that wasps often build nests in these structures.  Since wasps are beneficial – they prey on flies, caterpillars, and other insects – I don’t suggest wholesale eradication, but if nests are found near picnic, work areas, and dwellings, it may be advisable to apply an insecticidal product labeled for use against wasps.  Be sure to read and follow label directions; it’s the law!

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Speaking of passion:

• Harvest tomatoes which have cracks and use them immediately.  Split or cracked tomatoes left on plants will attract sap beetles and are also prone to invasion by decay-causing fungi.  Some varieties such as Celebrity, Early Girl, Jet Star, and Mountain Pride are resistant to cracking. However the best way to prevent cracking is to keep soil evenly moist through the growing season by watering and mulching the soil around tomato plants.

• Continue to check for insect pests in the vegetable garden.  Cucumber beetles, cabbage worms, tomato hornworms, corn borers and bean beetles are busy sampling the fruits of our labor.  The first option for pest control in vegetable gardens should be low impact or “biorational” pesticides, e.g. neem oil, spinosad, beneficial bacterial products.

• Prune raspberries after summer harvest is completed.  Cut out the old fruiting canes back to ground level.  Removing the old canes will help reduce the spread of cane blights while opening up the planting and allowing for more light to reach this year’s new growth.  This in turn will promote more fruit bud development.

• Cut some leafy shoots from purple-leaf varieties of shrubs, e.g. smokebush, weigela, and sand cherry, to complement the colorful blossoms in floral arrangements.

• Dig and divide irises, including bearded iris and Siberian iris.  Usually, bearded iris needs to be divided about every 3 to 5 years, while the faster growing Siberian iris may need to be divided more often, i.e. at 2 or 3 year intervals, in order to maintain maximum bloom.

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