Why you should plant now for permanence

Sunset, Oct, 1992 by Lynn Ocone

In mild climates, still-warm soils and soon-to-come rains get plants off to the best start. But availability of some plants is limited in fall

Tempting as it may be to buy perennials and shrubs in luscious spring bloom, fall is a better time to plant them in mild-winter regions. As the drawings at right show, a plant set out now has summer's peak heat behind, the probability of soaking rains ahead, and still-warm soil to encourage immediate and deep root growth.

But finding a good selection of trees, shrubs, and perennials in nurseries can be more difficult in fall, and many of the plants you do find are not in bloom.

Nurseryman Randy Baldwin of San Marcos Growers in Santa Barbara, California, puts it this way: "Impulse buyers usually don't plant in fall. But educated gardeners know the benefits of fall planting and seek out the plants."

Although fall is best for planting most permanent landscape plants, spring is best for frost-tender types like citrus, hibiscus, and bougainvillea. Also hold off planting perennials, trees, and shrubs of borderline hardiness.

Following are pros and cons of fall planting, as well as suggestions for finding and starting healthy plants now.

PRO: Plants set out in fall require less water

Water-wise gardeners have long recognized the value of fall planting, especially of such deep-rooted, unthirsty plants as ceanothus, manzanita, and toyon. As days shorten and nights lengthen, plants transpire less and require less water. Strong roots begin to develop in the warm soil, and soaking winter rains encourage them to penetrate deeper. And though most fall- and spring-planted trees and shrubs need regular water through at least their first summer, the fall-planted ones will have more extensive root systems that are better able to forage for water and withstand heat stress.

PRO: Fall planting gives plants a head start on growth

At nurseries, perennials such as delphinium, dianthus, and yarrow, and shrubs like India hawthorn and rockrose are at their most enticing in spring or summer bloom. But if you buy and plant them in bloom, they establish and grow slowly.

In contrast, if you buy these plants out of bloom in fall, they have the fall and winter to put out roots. Come spring, top growth--supported by more established root systems--will surge, and the plants will meet their full flowering potential. This is especially true for perennials that bloom in early spring, and for those that need a period of cold to ensure maximum bloom, such as campanula, columbine, coral bells, and foxglove.

PRO: Plants are less susceptible to certain root rots in fall

Plants set out in the heat of spring or summer need frequent watering--sometimes daily--to get established. But some plants, especially California natives such as fremontia, manzanita, and silktassel, are susceptible to soil-borne fungus disease if irrigated frequently when soil is warm. If you set out these plants in fall, winter rains will help establish their root systems when soil temperatures are cool. Then they'll need less frequent watering their first summer, when soil temperatures soar.

CON: Unless they're planted correctly, some perennials can rot in winter

Nonwoody (herbaceous) perennials planted in fall are more prone to rot in winter's cold, wet weather. To avoid rots, amend heavy soil with organic matter. Place plant crown at or slightly above the soil level, not below.

PRO: Some plants available in fall are fresher

Some nonwoody perennials at nurseries in fall were started from seed in late spring or summer. These are quite fresh; they're mostly available in cell-packs or 4-inch pots.

Plants left over from spring's inventory and offered in the same containers in fall may be rootbound. If possible, check the roots. They should not form a solid ball, and large roots should not grow out the drain holes.

Even if a plant in a 1- or 5-gallon container is rootbound, Ron Gass of Mountain States Wholesale Nursery in Phoenix maintains, "It's not a loss if you rootprune it." Gass recommends sliding the plant out of its container and using the blade of pruning shears to make two cuts opposite each other, about 1 inch deep, running the height of the rootball. This works most of the time, except on rare occasions when plants have become rootbound during the production stage at nurseries.

CON: Availability of some plants is more limited in fall

Many flower-bearing plants are out of bloom now, and in some areas nurseries' stocks are low. Baldwin suggests that gardeners ask their nurseries to special-order plants when necessary, since the plants are usually available through wholesalers.

Nurseries specializing in native and water-conserving plants, however, should be well stocked in fall. Native plant sales, often sponsored by botanic gardens and garden clubs in October and November, are another important source.

Check plant vigor and quality before you buy. Keep in mind that many Mediterranean and desert plants are dormant in summer; in early fall, they may look scruffy or partially deciduous. If the root system is healthy, don't be deterred. Once in the ground, they'll perk up. (To plant, follow steps at left).