The first step in gardening with perennials is to choose a site for the bed or border. Avoid spots that are boggy in the spring or fall, unless you particularly want to grow those perennials that are tolerant of wet feet.
The amount of light your garden receives will determine what sorts of perennials can be grown. Most people prefer to grow the sun or partial sun perennials, but there are plenty of perennials that grow well in full shade.
Deciding on a size and shape for your perennial garden is simply a matter of using your imagination to get the most out of the available space. Be generous in setting the proportions of your bed or border, as most perennials take more space than people realize. A good rule of thumb is to leave 2 feet of space between perennials, to allow for spread.
Absolutely all grass must be removed from a perennial garden before the first plant goes in. The quickest way to eliminate grass is to laboriously dig it out by the roots, taking pains not to leave even the smallest live piece.
Round-up herbicide gives excellent results, if you can wait two weeks after applying, and it leaves no residue in the soil. Heavy black plastic mulch laid over the sod will eventually kill all grass, but it may take half the growing season to do so.
With the grass subdued, till the soil and add organic matter in the form of peat, compost, leaf mold, sludge or manure. The last two materials should be used more sparingly, say half a bushel per square yard, than the first three. Lime the soil before tilling at a rate of one cup ordinary garden lime per square yard of garden.
Now that the soil is in shape, rake it smooth and cover itwith a 3-inch layer of mulch. Grass clippings, shredded leaves, oat straw, pine needles, or composted wood waste work fine as mulch, and you should plan on replenishing this mulch each year to maintain a 3-inch layer. This step will do more to insure the success of your garden and the ease of maintaining it than any other.
Mulch in place, it is time to move on to the fun part of establishing a perennial garden: choosing plants and setting them in. There are a wealth of reference books on perennials available at bookstores and garden centers. Choose a book with good pictures and be sure that it gives hardiness information for each species. To be safe, stick with perennials listed as hardy in zone 4 or lower.
Most perennial gardens are designed to be viewed from one side only, in which case the tallest plants will be placed at the back and the shortest at the front. Island beds or wide borders with viewing from both sides will be planted with the tallest plants in the middle and shorter types towards the outside.
Mixing and matching different species and varieties of perennials in your garden is largely a matter of personal taste. The best way to get started is to make a valiant first attempt, knowing that some plants will probably have to be moved later, when the color scheme or blooming sequence proves less than perfect.
Here lies the ongoing fun of perennial gardening: You are never really finished with a garden, and every year brings new surprises and challenges.
Michael G. Zuck is a horticulturist and the NEWS garden columnist.