I’ve recently started encountering large numbers of hover flies. These resemble sweat bees but have a single pair of wings and are unable to sting, though they can certainly be a nuisance. The type of hover fly we have is neither a beneficial or destructive insect. Their primary food source is decaying corn pollen left over after fertilization.
I’ve had calls asking about controls and there aren’t any I consider effective. Even if you were able to eradicate them from your property, they have wings and will fly in. Standard repellants often are ineffective. Some people have used brightly colored baits – hoverflies are attracted to bright colors, particularly yellow – and while this may kill large numbers of them, it also attracts them to an area.
The best advice I can give is to tolerate them and wait for their numbers to decline, which they will.
Fall Planting of Perennials
While landscapes are commonly planted in the spring, late summer and fall can also be a good time to establish a perennial bed. You should plant no later than the end of September to allow them time to establish their roots before cold weather arrives.
The first step is planning. Think about the space you will use. What is its purpose? Are you trying to show off the entrance to your home? Provide a border? Plant a bed which can be viewed from all sides? This will impact the size, location, and number of plants you will need. For borders, the tallest plants should be in the rear. For beds which will be viewed from all sides, taller plants should be in the center unless you are thinking of building a mound.
Once you have decided where to place your bed have the soil tested to ensure that it is appropriate for the plants you select. While many perennials, particularly native Indiana species, are tolerant of low soil fertility, they can be sensitive to soil pH. Does the area receive full sun, partial sun or is it shaded? Is it well or poorly drained?
Mass plants for color and seasonality of bloom. Massing also helps if one of your goals is attracting pollinators. Group plants according to other requirements such as water. For a more natural appearance, avoid planting in straight lines and use odd numbers of plants in groupings. Remember that too many different plants can create a chaotic appearance.
Make sure your bed is free of all grass and weeds. You may use chemicals however you can use a sod cutter instead. Once all vegetation is removed, loosen the soil to a depth of 8-12 inches. For native Indiana plants in undisturbed soils, little additional amendment is usually required. If your soil is predominantly clay you may want to amend it with 2-4” of organic matter such as compost or peat moss. Add amendments some time prior to planting to allow them to incorporate into the soil. If your soil test indicates a need for lime or fertilizer it is a good idea to add this at the same time. Phosphorous is a more important fertilizer than nitrogen in the fall. Phosphorous encourages root development. Nitrogen can encourage so much growth that plans do not adequately “harden off” before winter.
Avoid planting directly from seed in the fall. While this may be successful, your chances of establishing plants improves when they are planted from containers. Some nurseries sell plugs however you may need to buy a large number of each species.
Focus on weed prevention. Putting down a layer of wetted newspaper or cardboard can be very effective. Most newsprint uses soy ink but it is a good idea to check. Avoid newspaper printed with a petroleum-based ink. Mulch helps retain moisture, moderate soil temperature fluctuations, and control weeds.
Buy plants which show robust new growth, good color, and are free of pests. When planting, dig a hole the depth of the root ball and twice as wide. If the plant has a heavy root ball, cut through any circling roots. You may want to “tease out” roots if they are thick. When planted, the top of the root ball should be even with the soil surface. Pack the soil around it firmly by hand.
Once plants are in the ground, they should receive about one inch of water per week, either through rainfall or by supplemental watering. Continue this through the following growing season. Many native prairie plants may not need additional water after this except in a prolonged drought.
Another advantage of fall landscape planting is that homeowners often divide their existing plants at this time. If one of your friends has something you would like to incorporate into your garden, this may be an inexpensive way to pick up some plants.