At the Roots, Finding Room to Grow
Thursday, September 11, 2008
Q I have a mature red maple tree, and I want to landscape beneath it with azaleas and spring bulbs. The soil has not been improved for years, and the tree has a shallow root system. How can I improve the soil without damaging the tree? Is it all right to rototill the ground?
A You won't be able to till the ground with all those roots there. Add a layer of organic matter to the soil surface. Shredded leaves, compost or decayed manure are good options. In time, earthworms and other creatures will mix the amendments with the soil.
Planting will be a trial-and-error affair. You will have to probe the soil with your shovel several times before you find a spot where you can dig any kind of hole. If you can, choose small bulbs that thrive in shade, such as scilla, winter aconite, snowdrops and English bluebells. You will find them much easier to plant than daffodils and tulips, which need larger, deeper planting holes. Also, opt for small azalea plants. A young plant in a four-inch pot will be much easier to install than one in a standard two-gallon container.
Mosquitoes by the thousands, it seems, take over our back yard from May to October. We have used bug sprays, but they are only partially effective. Is there some form of spray or zapper we can use to reduce drastically the number of mosquitoes in our yard? We have young children, as do our neighbors, so we would like to know the safest option.
The most effective measure you can take is to search methodically for any source of standing water where the mosquitoes can breed. Target saucers on pots, toys, old tires, roof gutters and anything else that might hold water. Make it a neighborhood effort. If there are bodies of water that cannot be drained, drop in a briquette containing the Bacillus thuringiensis var . israelensis bacteria, or change the water at least once a week.
There are many trapping devices that may decrease the number of mosquitoes in an area. How well they work depends on the type of trap. Even the most effective, however, may not make a dent if you live near bodies of water.
In any home supply store, you can find many pesticides that are labeled for control of adult mosquitoes. Although it will kill the pests, a single spraying can provide only temporary relief. The problem is that even though the most persistent pesticides are more effective, they have the greatest negative impact on beneficial organisms. Area spraying is a lot of work for most homeowners and is typically reserved for municipal and state government mosquito-control efforts in swamps or wetlands.
Scott Aker is a horticulturist at the U.S. National Arboretum.