Analyzing Sun and Soil
The first task when considering a new plant for the garden is to make sure you have a suitable location for it. Plants can be moved, of course, but the more you know about the sun and soil availability in your garden, the easier you will find it to select the best location for your plants the first time.
Plant tags and catalogs usually describe a plant's need for sunlight as either "sun," "part shade" (or "part sun"), or "shade." These have specific meanings in the plant world:
"Sun" generally means at least 6 hours of full, direct sun each day. Sometimes a plant will even be described as needing "full sun," which means it should not receive much, if any, shade.
"Part shade" or "part sun" usually means that for about half the day, the plant should receive shade. (Sometimes you will even see this requirement listed as "half shade.") But it can also mean that a location receiving dappled light, such as is available beneath open, airy shrubs and trees, would work for this plant.
"Shade" means very little direct sun, but it does not mean deep darkness. Heavily dappled shade is fine, as are areas that receive direct sun only for an hour or two in the morning or late afternoon.
Of course, the time of year affects the amount of available sun. Many gardeners plan their new beds and borders during the winter, when many trees are bare and the garden can deceive us about the amount of available sunlight. Observe your garden in all seasons the first year to determine which areas remain sunny and which become shaded in the fullness of summer.
You may find, especially if you live in the far north or deep south, that the requirements listed on plant tags and in gardening catalogs do not match the needs of your plants. These requirements are based on the best general climate information, but you may need to provide more sunlight if you live in a cooler climate and more shade if your climate is hot. Some plants can take extra sunlight if they are watered more heavily; others will not flower or change foliage colors as effectively if given too much shade. And you can usually tell quickly if your plant is receiving too much sun: its foliage will appear burnt or will droop at midday.
Soil quality is probably the single most important factor in the long-term success of your garden. Without good soil drainage, most plants cannot thrive. Without adequate nutrition from minerals in the soil, they cannot grow. As a gardener you should learn what kind of soil your garden has, and then work to amend or improve the soil each season.
Soil types are often divided into "sand," "loam," and "clay." Sand is, as its name suggests, very porous, able to drain quickly, but it can also dry out quickly, and it may not be nutrient-rich. Loam is ideal soil, moderately moist but not wet, rich in minerals but not so heavy that air cannot circulate. Clay is heavy, compacted soil, usually rich in minerals but often poorly-draining.
To improve soil, add good amounts of organic matter. This can consist of everything from the contents of the compost bin to aged manure, peat moss, and decomposed leaves. Organic matter is rich in nutrients, and it helps both sandy and clay soils improve drainage. You can buy bags of composted materials to get the garden growing, and you might want to consider beginning a compost pile so that you can continue to feed the soil economically season after season.
Soil is also labeled as "acidic," "neutral," or "alkaline," which refers to its pH balance. Some plants require a certain pH level to grow their best. You might consider taking a soil sample to the local county extension agent for analysis; it is inexpensive and will help you determine which sorts of plants do best in your area.
Creating a New Bed or Border
One easy and economical way to create a new planting space is to clear the area you want, removing grass, weeds, and any other debris until the soil is bare. Then, as leaves begin to fall by the many thousand from your deciduous trees, rake and, if possible, shred them (many leaf-blowers have a reverse or vacuum setting, which shreds leaves quickly and very finely) and lay them onto the new planting area without even digging them into the soil. Add grass clippings and any other compostable matter you can find, including shredded newspapers and dead vegetable and annual plants. Water the new area thoroughly, and then cover it well with a tarp, securing the edges with stones or stakes to keep the moisture and heat in. When you uncover the area in spring, you should have rich, workable soil. It will have compacted a great deal, and you will want to turn and mix it with a shovel and rake, but depending on how much compost you were able to assemble, you may not have to dig into the soil below at all.
If you need to prepare a new bed or border for immediate planting, however, you will need to dig, as well as to buy or have ready large amounts of organic matter to add. Once again, clear the area of debris. Then spread a layer of organic matter several inches deep to the entire surface of the area. Beginning at once end, dig about a foot down into the soil, mixing the organic matter in as you go. (If you have a tiller, you can break the soil with it before adding the organic matter, but dig by hand to work the matter into the soil. Tilling tends to break the soil down too finely.) When you have finished, rake the area smooth and water it thoroughly. You are ready to plant.
A raised bed is any planting area that is set above the soil level. Raised beds improve soil drainage while avoiding the backbreaking work of turning hard-packed or unbroken soil. Most raised beds are enclosed (with sides made of wood, metal, rocks, etc.) to keep the soil piled high.
In addition to improving soil aeration and drainage, raised beds are useful for isolating the plants they contain from other parts of the garden, and for making cultivation of the garden easier. Vegetables are often grown in long, narrow raised beds that enable the gardener to weed and work them without stepping into the bed. They can be completely tilled under at season's end, and covered with a tarp over winter to build new soil for spring (see Creating a New Bed or Border). Quick-spreading or even invasive plants are best grown in a raised bed with sides that extend below the soil as well as above, although even these measures won't always stop a Bamboo or other underground-spreader from sending out rhizomes in all directions.
Raised beds give the garden a nice sense of architecture, and make gardening much easier. They are often built over boggy and other poorly-drained, infertile soils that have resisted all other attempts at improvement.
Adding Plants to an Existing Bed or Border
In a perfect garden, entire beds and borders would be prepared at once, enabling you to correct any drainage problems and aerate the soil. But in the real garden, opportunities to create an entire new planting area are few and far between, and most plants are added to existing areas, which may not have been tended for many years, and usually suffer from hard-packed soil, poor drainage, and plenty of rocks. The plants already thriving in these areas have deep, well-established roots that tap into water and nutrient sources well below the soil surface, and they can put up with plenty of stress, but a newly-transplanted perennial, shrub, or tree does not have this advantage, and will not be "established" in its new home for at least a year. It needs special treatment. (For complete instructions on newly-planted perennials, shrubs, and trees in the garden, see The Critical First Year.)
You might think, as gardeners did for many years, that the best way to get your new plants off to a great start is to dig a large hole, improve the soil and drainage to the best of your ability, and set the plant into its rich new home. The conventional advice was: "Dig a $1 hole for a 10-cent plant." Alas, not only are those 10-cent plants impossible to find these days, but unless you are growing annual plants, the idea itself has become outdated.
Perennials, shrubs, and trees that are put into planting holes enriched with organics and perfectly mixed tend to grow well until their roots spread beyond the boundaries of this idyllic nest. Once they hit the "poor" native soil surrounding the planting hole, they can struggle and even fail. So unless the soil in your planting area is completely unbroken or poorly-drained, it is best to set your new perennial plant into a small hole, not much wider and no deeper than the plant is used to from its pot (if it was grown in one) or the root spread (if it is bareroot). Trees and shrubs need a bit more horizontal spread, but no deeper hole. Roses are the most finicky, preferring at least some amendment at planting time and needing a large hole simply to fit their long, jutting, irregular roots.
Add some organic matter to give the soil a nutritional boost and improve aeration, but do not fertilize perennials, roses, shrubs, or trees at planting time. They need to expend all their energy at first growing roots, not trying to maximize their blooms or expand their branching. If you plant in spring, by the end of spring or beginning of summer the new plants will be ready for feeding, but they can safely go even longer if need be.
Note: Annual plants are the exception to all of these rules. Because they grow, flower, and die all in a single year, they should be planted in a well-enriched spot, fertilized regularly and heavily, and encouraged to give their all.