A PERENNIAL PRIMER

For the jaded gardener, these plants bring new form and color to the flower bed. But exactly what are perennials? And how can you best use them in your own landscape?

May we present perennials? Like a big box of new crayons, these plants give the gardener more to play with--a greater palette. All those colors and untried textures! There is such variety that you can truly find a perennial for any reason and for any season.

Perennials can quickly elevate a garden from the limited realm of marigolds and petunias and Pfitzer junipers and bring sophisticated textures and subtle colors to your landscape. And because perennials tend to linger and smooth the transition from one season to the next, the change in the seasons will seem far less abrupt--less like the click of a light switch.

What is a perennial? It is a plant that is neither as fleeting as an annual nor as woody as a shrub. It is difficult to be much more precise, because perennials are a huge and varied group of plants. They are the middle ground in nature and in the garden, smoothing the hard breaks and edges. Unlike annuals, which flaunt mostly bright colors, perennials can be bright and bold, or soft and subtle. You can have a garden that is a delicate hue of pink and lavender, or you can cast together golden yellow and bright blue for an entirely different effect.

Many perennials are grown merely for their foliage color or texture. Their leaves are seldom an ordinary green, and many are reddish or gray. Similarly varied is their form or shape. There are billowy perennials, mounding perennials and spire-like perennials. Very ordinary plantings of flowers suddenly seem extraordinary when the tall spires typical of many perennials appear in their midst.

Perennials have an honorable history in England, and to a lesser extent on our East Coast, but in California they were swept away by the tidiness of low-maintenance landscaping. Now, they are making a come- back, perhaps because our gardens are beginning to weather and are ready for a bit more complexity. Whatever the reason, you will see more perennials than ever at nurseries this spring and summer as growers and gardeners discover the value of these plants.

Most literature on perennials is of little help to Southern California gardeners, since it is more applicable to areas with harsher climates. And perennials are neither as perfect nor as troublesome as some of the writing about them would seem to suggest. The very diversity that makes them so attractive guarantees that growing them will be an adventure, especially in our area, where they behave so differently and where we can grow varieties that would not survive in harsher climates. Be prepared for some surprises--and some disappointments. Every perennial has a distinct personality that can be uncovered only after trial and error.

Unlike shrubs, perennials never develop persistent woody branches. Typically, they grow as clumps of stems that spread ever wider with each passing year. These are the perennials of garden literature-- herbaceous perennials--cyclic plants that grow and flower in spring and summer, die to the ground in winter, and return the following spring from roots that function much like bulbs. In England and in the eastern United States, they are governed by the definite seasons and thus perform to a strict timetable. Expert English gardeners have learned to control that cycle with astounding precision, but such schemes are pointless in Southern California’s casual climate. Here, perennials come and go as they please, often ignoring the seasons.

Also, these herbaceous perennials often behave very differently in this area. Veronicas are a fine example, blooming not once, but as many as three times a year. The traditional regimen for herbaceous perennials is to cut them to the ground after they have flowered. In colder climates, that customarily is done in late summer or early fall, and it prepares the plants for winter dormancy. In Southern California, if you cut back veronicas after they flower (and you should), six weeks later they’ll flower again, and again. They simply don’t see any reason to quit in our mild weather.

To confound matters, we also grow all sorts of perennials that are not strictly herbaceous. At the very least, a tidy clump of foliage will persist through our mild winter, but an occasional flower in winter is almost as likely. There are even a few perennials that are at their best when every other plant in the garden is not.

It should be clear that any general discussion of perennials is difficult. Nevertheless, on the following four pages you will find specific information on some of the most commonly available perennial plants.

Perennials can be said to have this in common: They need more care than most plants. There are exceptions--agapanthus is an example--but to suggest anything else would be misleading. Except for the initial planting, most of this care is of the pleasant sort--cutting back, tidying up, fertilizing, dividing and replanting (giving neighbors and friends cherished bits and pieces) and the like. Some people call this puttering. And, since it doesn’t happen all at once, you can easily keep up with even a large flower bed.

The exception--and the big chore--is planting. That is best done in the fall, but it is usually done in early spring, since that is when perennials are most plentiful at nurseries. Planting is plain hard work because perennials demand the best soil.

Prodigious plants, they grow fast in the spring and flower heavily. Many can easily compete with annual bedding plants, covering themselves with flowers for months at a time. But to do that, for even a year, they need a rich, healthy soil. And unlike annuals, perennials may stay in one location for several years, so soil preparation at planting time must be premised on that supposition. Thoroughly dig the soil and mix in lots of organic matter and fertilizer. That cannot be overemphasized.

In time, most perennials will need to be dug out and divided, because they rapidly deplete the soil. You will begin to notice fewer flowers, the signal that it is time to divide. Dividing means exactly that--you split the plant into pieces, remembering that most perennials are clumps of individual stems. A sharp spade is essential. Dig up the clump, split it with the spade, replenish the soil and replant. That work is usually spread out through fall and winter, when plants are most dormant.

Some perennials spread outward, with the center of the clump eventually dying out. Again, the solution is to dig and divide. A few perennials cannot be divided because, rather than growing as a collection of stems, they appear more like a small bush or annual with one main stem. When those plants wane, they need to be replaced, but many are easy to root as cuttings.

We would also be less than honest if we didn’t warn you about the perennial garden in winter. Though some perennials remain quite respectable and some are at their peak, others are in disgrace during the winter. It is their time of year to rest, and perennial plantings can look quite forlorn then. The challenge to the gardener is to turn that disheveled look into one of peaceful, wintry repose by trimming everything carefully, mulching bare soil and perhaps planting, in the fall, spring annuals and bulbs that will bloom in winter--or at least be bright and green. November and December are probably the low points of the year for perennials, but by March, everything will be growing again.

Many perennials bloom their best in May and June. That tendency should be capitalized upon, since that is the time of year when beds of annuals are in an awkward in-between stage; spring’s flowers and bulbs are gone, and summer’s haven’t arrived yet. There are also a few perennials that bloom in the fall or late summer, looking their freshest when everything else is exhausted.

Many of the perennials described in this issue are often treated as annuals. Delphiniums, for instance, are perennials, but in California they are usually replanted yearly. However, even when they’re treated as annuals, they do not behave as such. Delphiniums bloom in spring or early summer, but if they’re cut back, they will repeat their show in the fall--on a smaller scale. Perennials such as coreopsis and penstemon will bloom most of the year, not merely for a season, although they, too, are often replanted yearly.

How to use perennials? The traditional perennial border contains only perennials, but in Southern California, perelnials can be casually mixed with small shrubs, annuals, bulbs, herbs, ground covers or anything you like--even roses. If you want to begin cautiously, mix in a few perennials with your summer bedding plants. Golden-yellow coreopsis will make a bed of zinnias sing, and blue salvia will add some snap to a bed of marigolds.