Transplants will produce a display of flowers several weeks earlier than direct-seeded plants. This is especially true for annuals such as scarlet sage and verbena, which germinate slowly or need several months to bloom from seeds.

Annual flowers can be purchased at a variety of retail businesses in the spring. Buy only healthy plants, free of insects and diseases. Retailers often purchase flowers from a wholesale grower instead of growing the plants themselves. While the quality of plants is often excellent when they first arrive, some retailers are not plant experts or are not equipped to properly care for plants. Do not purchase plants that have not been watered properly or that have been stored under stressful conditions (hot, paved surfaces) for extended periods. It is a good idea to ask when the plants arrived or if a new shipment will be arriving soon. Freshly stocked plants are preferable to plants that have been held for several weeks. Choose plants with compact foliage, side branches, and good color. It may be tempting to select the plants that are in bloom, but younger, nonflowering plants are often a better choice, since they will establish in the landscape more quickly.

Wait until the proper planting time to purchase plants. Transplants are often available before the correct planting time, but tender annuals should not be planted before the danger of frost has past. Hardy annuals, such as pansies, should not be planted until the soil has cooled in the fall. Planting too early can result in cold damage in the spring or heat damage and disease in the fall.

Sometimes new plants cannot be set out immediately after purchase. Keep plants outdoors in a partially shaded location and check them daily and water as needed. Since the soil volume is limited in the small containers, they will dry out quickly. While plants may appear to recover fully, wilting can stunt their potential growth.

Plants in cell packs or containers should be watered thoroughly and allowed to drain before removal from the container. A damp root ball is less likely to fall apart. Do not pull plants from their containers. Remove plants from individual containers by tipping the container and tapping the bottom. To remove plants from cell packs, turn the container upside down and squeeze the bottom of the container to force the root ball out of the pack . If the plants are in fiber pots, remove the paper from the outside of the root mass. When setting out plants in peat pots remove the upper edges of the pot so that the lip of the peat pot is not exposed above the soil level where it will act as a wick and pull water away from the plant.

Figure 14-1: click to see larger version

Dig a hole for each plant large enough to accept its root system comfortably. Set the plants at the same depth or just slightly deeper than they were growing in the container. When filling the hole, firm the soil lightly and water thoroughly. A starter solution made from 1 tablespoon of a high grade phosphate fertilizer in 1 gallon of water can be used to water transplants.

Space plants so that they will fill in but not be crowded; crowding increases the likelihood of disease development. Tall, upright plants such as snapdragons should be spaced about one-fourth as far apart as their mature height. Tall, bushy plants should be spaced about one-half as far apart as their mature height. Rounded, bushy annuals should be spaced about as far apart as their mature height. To make beds look more uniform, use a staggered spacing plan instead of setting plants in straight rows. Transplant in the cool part of the day or on an overcast day to minimize stress and check newly planted transplants for moisture stress frequently until new roots have had time to grow into the surrounding soil. Remember that the root mass is initially only as large as the original container, so apply irrigation water toward the base of the plant until it becomes established.

A mulch should be applied after planting. Mulches help keep the soil surface from crusting, reduce soil temperature, conserve moisture, and prevent weed seed germination. Organic mulches can add humus to the soil. Use a 2- to 3-inch layer of material such as pine bark nuggets or pine straw. Apply only 1/2 inch of mulch at the plant crown; excessive mulching around the crown can create disease problems.

Prepared by: Erv Evans, Consumer Horticulturist

© 2000 NC State University
Images © by Erv Evans