Finally, it’s summer! Both by the calendar and by the temperature and behavior patterns. To a St. Louisan, it means that Memorial Day has come and gone, so the white pants and sandals can enter the wardrobe and it’s the best time to plunge into gardening. With peas to pick, veggies to plant and weeds to pull, it could easily be a full-time occupation.
This spring has been the coolest, dampest one in my memory, averaging nearly two degrees below normal, and the wettest May in recorded history. On the plus side, it has graced us with fabulously long spring blooms on magnolias and azaleas, daffodils that lasted more than a month and iris displays that caused me to swoon. On the down side, it has also left us with muddy patches in our lawns that are breeding mosquitoes and wet, moldy basements.
If one cold, wet spring has you questioning global warming, my recommended reading is at www.arborday.org/media/mapchanges.cfm. Download and play the animation that shows the changes in winter cold hardiness from the 1990 USDA map that lists us at the edge of Zone 5 to the 2006 Arbor Day Foundation map, based on actual temperature data, which puts us squarely in the middle of Zone 6. That may not mean a whole lot yet to anyone who is not an avid gardener, but it tracks a change in our growing conditions that is measurable.
Gardeners always love a challenge and push the edges of their growing zones pretty hard. My NC State classmate Tony Avent says, “I don’t believe it won’t grow in my garden until I have personally killed it three times.” So, with special sheltered microclimates in protected locations, we have often been able to cheat Mother Nature by a zone or two most years. Last year, we planted several new varieties of camellias in the Missouri Botanical Garden that have been selected for better cold hardiness. This year, we watched them all bloom. Outdoors. In St. Louis. Camellias! As far as I know, this is a first for our locality, the first of many delightful gems we will add to milder gardens.
Before you start doing your garden happy dance and race to the Internet to buy camellias, realize that two conditions apply—specially selected varieties and warmer winters. The down side of this change is that fire ants will be moving north, along with armadillos. If you think raccoons mess up your new beds, just wait for the armadillos. At Mercer Arboretum and Botanical Garden (in north Houston, where I spent many happy years fighting fire ants) the ‘dillos would wait for the last gardener to go home after a hard day on their hands and knees digging in new bedding plants. They then would sneak in at dusk, uproot all the new annuals, toss them out on the lawn to die in the early morning sun and feast on the grub worms underneath. Gone by dawn, they would leave havoc and destruction behind. Armadillos already have arrived at our Shaw Nature Reserve in Gray Summit.
Southern gardens have other pests, too, like mosquitoes the size of whooping cranes. Recognized by some as the Texas state bird, they carry dangerous human diseases like West Nile Virus, encephalitis and malaria, as well as spread canine heartworms.
Sharing a barbecue with these voracious blood sucker insects is not fun. After years of dealing with them in Texas, I’ve learned a few tricks. Here are several simple things you can do to make your evening garden bite free.
It is easier to control breeding sites and eliminate larvae than it is to kill adult mosquitoes. To reduce standing water, police your terrace and garden for anything that can hold water, like pot saucers, puddles in canvas furniture covers, kiddy wading pools or fire pits with plugged drain holes, and empty them. It only takes a few tablespoons of water to host a block party for baby mosquitoes. If you have an ornamental pool or pond, have fish. They love to eat mosquito larvae. Next, check your rain drainage system (gutters, downspouts, French drains) to make sure they are not blocked. Look into knot holes in trees, and catch basins and storm sewer inlets to see if there is standing water present. If there is water in places that cannot be drained, use Mosquito Dunks, little doughnuts laced with BTI (Bacillus thuringiensis ssp. israelensis), a biological larvicide toxic only to insect larvae and safe for humans, pets, fish and birds. Lasting 30 days or more, these small tablets are ideal for larva control in storm drains, rain barrels, bird baths and fountains.
If you flunked Lesson One and have a major problem with biting adults, you will need to move on to the next session.
Adult Mosquito Control
You can buy a big, fancy CO2 and pheromone-baited mosquito destruction device. I have one, industrial-sized, and it gives reasonable control for half an acre or so. Just plug it in, add a CO2 canister and fresh pheromone pad, and spend your summer swat-free. These machines really do work. The amount of carbon dioxide they release is less than your car puts out in one trip to the mall.
Add a ceiling fan. Not hanging from your trees, silly! An outdoor-rated fan on the porch or arbor sets up enough wind velocity to make it hard for hungry mosquitoes to land. We’re adding one in our garden and another for the adjacent seating area this season.
As a last resort, spraying or fogging with pesticides can help control adult mosquitoes. The safest material to use is a pyrethrum-based spray. This biological chemical is actually extracted from pyrethrum daisies. Just remember that ‘natural’ doesn’t mean non-toxic. It will kill your desirable pollinators and friendly insects as well. If you want to have honey bees and butterflies in your garden, go back to Lesson One.